JP4716738B2 - Pipeline evaluation method - Google Patents

Description

  The present invention relates to a pipeline evaluation method.

  In recent years, in the water supply business, it has become extremely important to perform maintenance management such as grasping the state of an existing pipe network and making an update plan for the pipe network. For example, in consulting services related to pipe networks, we evaluate which important pipes have a major impact on the entire pipe network due to the occurrence of water leaks, etc., and provide the results to customers. ing.

  The above-mentioned important pipelines can be evaluated based on the result of pipe network calculation performed on the pipe network. Pipe network calculation means each condition under given conditions such as the head of the water source, the arrangement of the pipe, the diameter of the pipe, the demand of water taken from the node as the demand point of water (hereinafter referred to as the quantity of water taken out). It means calculating the flow rate of the pipeline and the head of each node.

  Here, a method for evaluating a pipe line based on the result of pipe network calculation will be described with reference to FIGS. This evaluation method includes a preparatory process for performing an evaluation, a calculation process for calculating an evaluation value to be used for evaluation using the result of the preparatory process, and an evaluation for setting a pipeline to be evaluated after the calculation process. It has a setting process of an object pipe line, and an evaluation process of evaluating each pipe line based on the calculated evaluation value. For example, when performing pipe network calculation for a pipe network constituted by the network relationship of the water source S1, the pipe lines K1 to K8 and the nodes N1 to N6 as shown in FIG. Various initial data are given as shown.

That is, for the water source S1, the LWL (Low Water Level) [m] as the head of the water source, the ground height [m] as the head of the installation height of the water source S1, and the nodes N1 to N6 are taken out per unit time. For the amount of water [m ³ / s] and the ground height [m], which is the head of the node, and the pipes K1 to K8, the start point, end point, flow velocity coefficient, pipe length [m] and pipe inner diameter [mm] are given. It has been. Further, the amount of water used per person and per day, W [liter / day · person], is also given as initial data.

  In the calculation of the pipe network, the Hazen Williams empirical formula (shown in the following formula 1) is used to find the loss head when water flows from one end side to the other end side of the pipe.

In Equation 1, h is a head loss [m], q is a flow rate [m ³ / s], C ₀ is a flow velocity coefficient, D is a pipe inner diameter [m], L is a pipe length [m], and r is The resistance coefficient of the pipe (hereinafter referred to as pipe resistance). The pipe resistance r is a constant determined by the flow velocity coefficient C ₀ , the pipe inner diameter D, and the pipe length L. Further, r ′ is expressed by Equation 2 when a value obtained by partial differentiation of the loss head h [m] with the flow rate q [m ³ / s] is r ′.

In the following, this r ′ is referred to as variation resistance.
Under the conditions as described above, in order to perform the pipe network calculation by the mesh flow method for the pipe network shown in FIG. 6, first, as shown in FIG. The initial data of the pipe network is read as shown in FIGS. At this time, the data to be read is, for example, numerical data as shown in FIGS.

  Next, as step 2 (S002), based on the data read in step 1, as shown in FIG. 10, the water source S1, nodes N1 to N6, and pipelines K1 to K8 are connected, and the network relationship in the pipeline network Build up.

  At this time, the node N7 connected to the water source S1 through the pipe E1 is applied to the calculation theory of the electric network in the pipe network calculation in which the amounts of water c1 to c6 taken out from the nodes N1 to N6 are respectively constant. A reference node (head of water = 0) that is virtually provided for application, and the reference node N7 and the pipeline E1 that are virtually provided can be created by a known method. For this reason, detailed description about creation of the reference node N7 and the pipe E1 is avoided here. In addition, the arrow in a figure has shown the direction of the pipe lines K1-K8 and the pipe line E1. At this time, the direction of the pipelines K1 to K8 may be arbitrary, but the direction of the pipeline E1 is set so as to be directed to the reference node N7. Moreover, the data about the pipe line E1 are shown in FIG. As shown in FIG. 11, the starting point of the pipe E1 is the water source S1, the end point is the reference node N7, and the head of this reference node N7 is set to 0 [m], so the head difference between the start point and the end point is A [m].

  Next, as shown in FIG. 9, as step 3 (S003), a breadth-first tree is searched based on the graph theory. In general, a tree in graph theory is defined as a subgraph (here, corresponding to a pipe line) that includes all points (nodes) and does not have a closed circuit (loop). , A tree obtained by searching so as to branch as much as possible from the root (reference node).

  Since this breadth priority tree search can also be performed by a known method, a detailed description of the method is avoided here. The result of the breadth-first tree search performed in step 3 is shown in FIG. As shown in FIG. 12, a pipe line with a breadth-priority tree is represented by a solid line as a tree branch, and a pipe line without a breadth-priority tree is represented by a broken line as a complementary tree branch.

  Next, in step 4 (S004), it is assumed that water does not flow through the pipelines K4 and K5 that have been made as complementary tree branches in step 3, and the amount of water taken out from each of the nodes N1 to N6 is c1 as shown in FIG. Based on the fact that it is ˜c6 (= constant), the fixed flow rate a (= constant) of the pipe lines K1 to K3, K6 to K8, E1, which are tree branches, is set. At this time, for example, the fixed flow rate a (K1) of the pipe line K1 is represented by the sum of the amounts of taken-out water c1 to c6 of all the nodes on the downstream side of the pipe line K1. Further, there is no amount of water taken out from the reference node N7, and conversely, the sum of the taken-out water amounts c1 to c6 of all the nodes N is supplied from the water source S1, so that the fixed flow rate a (E1) of the pipe E1 Is given a negative sign. Accordingly, the fixed flow rates a (K1) to a (K8) and a (E1) of the pipelines K1 to K8 and E1 are expressed by the following equation (3). The fixed flow rate a is a set value not related to the pipe resistance r of each pipe line. Further, in the following, when it is not necessary to specify for which explanation the fixed flow rate of the pipe line is, it is referred to as a fixed flow rate a.

  Next, in step 5 (S005), the adjacent relationship between the meshes formed in the pipe network is searched. The mesh here is a region that is surrounded by branches (tree branches, complementary tree branches) in the plane graph and does not include branches inside.

  From the conditions shown in FIG. 7 and FIG. 8 and the result of step 2, the meshes in the pipe network are mesh 1 and mesh 2 as shown in FIG. 13, and mesh 1 and mesh 2 are pipeline K8. Recognize that they are adjacent to each other.

Then, it is assumed that a flow is generated in the mesh 1 and the mesh 2 in an arbitrary direction (clockwise direction in the drawing), and a circulation flow rate circulating through the mesh at that time (hereinafter referred to as a mesh flow rate). Are m1 and m2 [m ³ / s] (= variable). The mesh flow rates m1 and m2 are also set values that are not related to the pipe resistance r of each pipe, as in the case of the fixed flow rate a. Further, in the following, when there is no need to specify which mesh flow rate is in the description, it is referred to as a mesh flow rate m.

  Since the flow rate q of each branch (pipe) is the sum of the fixed flow rate a and the mesh flow rate m, the flow rate q (K1) in each branch (pipe) is determined from the values of the fixed flow rate a and the mesh flow rate m. -Q (K8) and q (E1) are derived. If the direction of the fixed flow rate a and the direction of the mesh flow rate m are the same when deriving the flow rate q, the value of the mesh flow rate m is added to the value of the fixed flow rate a, and the direction of the fixed flow rate a and the direction of the mesh flow rate m are reversed. If it is oriented, the value of the mesh flow rate m is subtracted from the value of the fixed flow rate a. If it does in this way, flow volume q of each pipe line will be expressed like a number 4 using mesh flow volume m1 and m2. In addition, when it is not necessary to specify which branch (pipeline) the flow rate is in the description, the flow rate is indicated as q.

  Here, as shown in FIG. 14, when it is assumed that the flow is generated in an arbitrary direction (clockwise direction in the drawing) in the mesh, the flow head has a positive flow head h in the same direction. When a negative sign is given to the loss head h of the pipe in the reverse flow direction, the sum Σh of the loss head of each pipe constituting the mesh becomes 0. Therefore, as shown in FIG. For the mesh 2, Equation 5 holds.

  At this time, the formula expressed by Formula 5 is expressed as Formula 6 from Formula 1.

  Since the extracted water amounts c1 to c6 and the fixed flow rate a are constants from Equation 3, the equation represented by Equation 6 is a nonlinear simultaneous equation with the mesh flow rate m1 of the mesh 1 and the mesh flow rate m2 of the mesh 2 as variables. It becomes.

  The solution of the nonlinear simultaneous equations is obtained by iterative calculation by the Newton-Raphson method in a later calculation process. At this time, it is already known to use the calculation formula shown in Equation 7.

J is a Jacobian matrix, and ΔM is a correction vector for correcting the value of M = (m1, m2) ^T (T represents a transposed matrix). At this time, the component [j _ij ] of the Jacobian matrix J is expressed by the equation shown in Equation 8.

In particular, the component [j _ij ] of the Jacobian matrix J at the time of calculating the pipe network using the mesh flow method is based on experience from the adjacent relationship between the meshes searched above, that is, the network relationship constructed in Step 2. Can be based on. Accordingly, in step 6 (S006), from the result of step 5, the Jacobian matrix J is determined as shown in equation (9).

Specifically, since the number of meshes formed in the pipe network is two, the Jacobian matrix J is determined to be a 2 × 2 matrix, and the diagonal component j ₁₁ of the Jacobian matrix J is determined. values, line K2 constituting the mesh 1, K3, K4, Shun Kazu of variation resistance K8, _and the value of _{j 22,} conduit K5 constituting the mesh 2, K6, K7, The sum of the variation resistance of K8.

Further, j ₁₂ and j ₂₁ values which are non-diagonal components of the Jacobian matrix J are used as the values of variation resistances of the pipe K8 shared by the mesh 1 and the mesh 2 (the number of shared pipes is plural. In this case, the sum of those variational resistances is set to 0, or 0 if not shared, and since the flow direction of the mesh 1 and the flow direction of the mesh 2 are opposite, the sign is negative ( If the direction is the same) The Jacobian matrix J is determined as described above, and the calculation formula shown in Equation 7 is determined. However, at this point, the variation resistance of each pipeline is unknown.

Here, in order to make it easier to calculate the inverse matrix J ⁻¹ of the Jacobian matrix J determined in step 6 in a later step, a commonly used LU decomposition or the like may be applied to the Jacobian matrix J.

  Although the preparatory process for evaluating the pipeline by the above steps 1 to 6 was performed, the above preparatory process is a process that can be performed based on the network relation of the water source, the pipe line, and the node. In particular, this is a process that can be performed regardless of the pipe resistance r of each pipe.

  Next, as shown in FIG. 9, as a calculation process, as step 7 (S007), arbitrary initial values for starting iterative calculation by the Newton-Raphson method are set in the mesh flow rates m1 and m2, and step 8 In (S008), the value of the flow rate q in each pipeline is calculated from Equation 4.

  Next, when the value of the flow rate q in each pipeline is obtained, the variation resistance r ′ in each pipeline is obtained from Equation 2 as step 9 (S009). In step 10 (S010), F (M) is calculated by substituting the flow rate q of each pipe line into Equation 6.

Next, in step 11 (S011), the absolute value of each value of f1 (M) and f2 (M) obtained in step 10 is, for example, larger than 1.0 × 10 ⁻⁶ set as a threshold value. Determine if it is small.

At this time, if the absolute values of the respective values of f1 (M) and f2 (M) are not smaller than the threshold value 10 ⁻⁶ , the value of the mesh flow rate m is larger than the value of the mesh flow rate m satisfying Equation 5. The process proceeds to step 12 (S012) assuming that there is a large deviation.

In Step 12, the value of the variation resistance r ′ of each pipeline calculated in Step 9 is substituted into the Jacobian matrix J determined in Step 6, and based on this, the inverse matrix J ⁻¹ of the Jacobian matrix J is calculated. , Equation 10 is derived.

Then, the simultaneous linear equation shown in Equation 10 is solved to calculate the value of the correction vector ΔM.
Next, in step 13 (S013), the values of the mesh flow rates m1 and m2 used for the current calculation (initial values in the case of the first calculation) are corrected by the calculated correction values Δm1 and Δm2. That is, when M at the time of the k-th calculation is expressed as M ^k , M ^{k + 1} used in the next calculation is M ^{k + 1} = M ^k + ΔM ^k .

Then, returning to step 8, the mesh flow rate is set to M ^{k + 1} which is a corrected value, and the calculation of step 8 to step 11 is performed. Until f1 (M) and f2 (M) satisfy the threshold condition, Newton · Performs iterative calculations using the Rafson method.

In step 11, when the values of f1 (M) and f2 (M) are smaller than the threshold value 10 ⁻⁶ , the value of the mesh flow rate m used in the calculation at this time satisfies Equation 5. The iterative calculation is terminated assuming that the solution is sufficiently close, and the process proceeds to step 14 (S014).

  In step 14, the values of the mesh flow rates m1 and m2 used for the current calculation are set as solutions of the nonlinear simultaneous equations. Then, using the values of the mesh flow rates m1 and m2, the flow rate q in each pipeline is obtained based on Equation 4, and the loss heads h (K1) to h (K8) in each pipeline are obtained from Equation 1. Ask for. In addition, when it is not necessary to specify for which explanation it is a loss head of which pipe line, it is described as the loss head h.

  As shown in FIG. 15, since the difference between the LWL and the dynamic water level is the loss head h, and the difference between the dynamic water level and the ground height is the effective water head as the pressure head, it is given as initial data in advance. From the values of LWL, ground height H, and calculated loss head h, the effective heads P (N1) to P (N6) [m] at each of the nodes N1 to N6 and the effective head P (S1) of the water source S1 are used as evaluation values. calculate.

  For example, the effective heads P (N1) and P (N6) of the nodes N1 and N6 and the effective head P (S1) of the water source S1 are obtained by the following equation (11).

In addition, the effective heads P (N2) to P (N5) other than the above are obtained in the same manner.
Then, values such as the flow rate q, the loss head h, and the effective head P obtained by calculation are recorded. In addition, when it is not necessary to specify the effective head at which node, it is indicated as effective head P.

The effective water head P obtained as described above is for a pipe network in a normal state (complete state).
Next, as an evaluation target pipeline setting process, in step 15 (S015), if the pipeline to be evaluated is erased, it is returned to the original position, but the first calculation is the evaluation target. Since the process is performed on the pipe network in a normal state without deleting the pipe line, the process proceeds to step 16 (S016).

  In step 16, it is determined whether there is another pipeline to be evaluated. As described above, the first calculation of the pipe network is performed on the normal pipe network without deleting the pipes, and each pipe line must be evaluated next. Proceeding to step 17 (S017) assuming that there is a pipeline.

In step 17, if the pipe to be evaluated is, for example, pipe K2, the pipe K2 is deleted from the pipe network as shown in FIG.
When the pipe K2 to be evaluated is deleted from the pipe network in the normal state, the connection relation of the water source S, the node N, and the pipe K after the pipe 2 is deleted, that is, the network relation of the pipe network is newly constructed. Therefore, the process returns to step 2 as shown in FIG.

  Then, for the pipe network in which the pipe K2 has been deleted, preparatory steps such as the construction of the network relation of the pipe network and the search for the breadth-priority tree are performed. A calculation formula for calculating the evaluation value is derived.

  That is, in the preparation process, steps 2 to 6 are executed again. FIG. 17 shows the result of the breadth-first tree search in the pipe network in which the pipe K2 is deleted. In this case, the fixed flow rate a of the pipelines K1, K3 to K8, and E1 is expressed as in Expression 12.

  Further, as shown in FIG. 17, a mesh 1 is formed on the pipe network, and the flow rate q of each pipe line using the mesh 1 is expressed by the following equation (13).

As a result, the following Expression 14 is established for the mesh 1.

At this time, the equation expressed by Equation 14 is expressed as in Equation 15 below from Equation 1.

  Further, ΔM and F (M) in the above equation 7 are respectively expressed as the following equation 16.

Further, since the number of meshes formed in the pipe network is one, the Jacobian matrix J is represented by a 1 × 1 matrix as shown in the following Expression 17.

  Then, the process moves to the calculation process, and Steps 7 to 14 are executed again to perform the iterative calculation by the Newton-Raphson method, the flow rate m1 of the mesh 1 is obtained, and the pipe K2 is erased based on the flow rate m1. The flow rate q of each pipe line in the pipe network, the loss head h, the nodes N1 to N6, and the effective head P of the water source S1 are obtained.

The effective head P obtained as described above is for the pipe network in which the pipe K2 has been deleted.
Thereafter, in step 15, since the calculation is performed when the pipeline K2 is deleted this time, the pipeline K2 is returned to the original position.

  Thereafter, similarly to the above-described pipe K2, the pipes K3 to K8 and K1 are sequentially deleted one by one through the steps 16 and 17, and the pipe network in a state where the pipes K3 to K8 and K1 are deleted. The flow rate q of each pipe line, the loss head h, and the effective head P of the nodes N1 to N6 and the water source S1 are obtained.

Then, when there is no pipeline to be evaluated, the process proceeds to step 18 (S018).
As an evaluation process, in step 18, an index for evaluating which important pipeline has a great influence on the entire pipe network is calculated. Here, the target population for low pressure is obtained as an evaluation index.

  The population to be reduced in pressure is an index indicating the population affected by the water cut due to a pressure drop when the evaluation target pipeline is cut off, and is calculated based on the following equation (18).

In the above formula 18, LDa is the population [person] subject to low pressure when the evaluation target pipeline is deleted. Further, S _i is the water supply population set at each of the nodes N1 to N6, and the amount of water taken out from the nodes N1 to N6 as the initial data shown in FIG. 7 per unit time c1 to c6 [m ³ / s] and the amount of water used per person and per day W [liter / day · person] is calculated based on the following equation 19 and becomes a constant value at each of the nodes N1 to N6.

Also, the _{F i} is a value corresponding to the presence or absence of water outage at each node N1 to N6, effective hydrocephalus P in each node N1~N6 (N1) ~P (N6) is 10 m (= 0.098 MPa: predetermined value ) When it is below, it is determined that there is water breakage, and when it is larger than 10 m, it is determined that there is no water breakage and 0.

For example, assuming that the values of F _{1 to} F ₆ corresponding to the nodes N1 to N6 are as shown in Table 1 below when the pipeline K2 is deleted, the low-pressure target population LDa (K2 when the pipeline K2 is deleted) ) Is as shown in Equation 20 below.

  Further, in the same manner as described above, the respective low-pressure target populations LDa (K3) to LDa (K8) and LDa (K1) corresponding to the cases where the pipelines K3 to K8 and K1 are deleted are calculated. It means that there are many populations which are affected by a water break, so that a value is large among each low pressure object population LDa (K1)-LDa (K8) calculated | required in this way. It evaluates that it is a pipe line with high importance in an order from the pipe line from which the value of object population LDa (K1)-LDa (K8) becomes large. In the above conventional example, as shown in FIG. 6, since eight pipe lines K1 to K8 are provided in the pipe network, the evaluation target population is calculated by deleting the evaluation target pipes one by one. Thus, a total of eight types of low-pressure target populations LDa (K1) to LDa (K8) are calculated.

Japanese Patent Application Laid-Open No. 2004-228561 describes a technique that can perform pipe network analysis while efficiently using a computer memory that performs calculation on the pipe network.
JP-A-6-274576

  In the above conventional format, based on the idea that any one of the pipes K1 to K8 becomes unusable one by one, the pipes K1 to K8 are erased one by one as the evaluation target pipes, and the population targeted for low pressure LDa (K1) to LDa (K8) are calculated, and the importance of each of the pipelines K1 to K8 is evaluated one by one.

  However, in reality, if a valve is provided in the pipe network and any one of the pipes in the pipe network becomes unusable due to an accident, the neighboring valve is closed, and the pipe where the accident occurred In addition, a plurality of pipelines may become unusable at the same time.

  Therefore, in the above conventional method, based on the idea that one of the pipes falls into an unusable state one by one, each pipe is deleted one by one and the importance of each pipe is evaluated. At the same time, the pipes are evaluated in a state different from the actual state of the pipe network in which a plurality of pipes cannot be used, and there is a concern that the accuracy of the calculated evaluation results is inferior.

  The present invention is capable of obtaining a more accurate evaluation result by evaluating a pipeline that affects the pipeline network in a state closer to the actual pipeline network in which a plurality of pipelines may become unusable at the same time. An object is to provide a method for evaluating a possible pipeline.

In order to achieve the above object, the first invention comprises a network relationship of an arbitrary number of water sources, a plurality of water demand points, and a plurality of pipelines to which the water sources or demand points are connected at both ends. When evaluating a pipeline that affects the pipe network in the pipe network, a preparatory process for performing the evaluation, and a calculation process for calculating an evaluation value used for the evaluation using the result of the preparatory process And an evaluation method for a pipeline for performing a setting process for setting an evaluation target group and an evaluation process,
In the preparatory step, the network relationship is established, the pipelines are divided into a plurality of groups, and a calculation formula for calculating the flow rate of each pipeline in the pipeline network is derived based on the network relationship.
In the above calculation step, the flow rate of each pipeline is calculated using the above formula, and the loss head of each pipeline is calculated by substituting the calculated flow rate of each pipeline into the following Hezen-Williams formula (a). The above evaluation value is calculated based on the calculated loss head of each pipeline,
In the above setting process, the evaluation target group is determined from each group, the pipelines included in the evaluation target group are deleted from the pipe network,
After the pipeline is deleted, the process returns to the preparation step, and a new network relationship is established for the pipeline network from which the pipeline in the evaluation target group has been deleted. Based on the new network relationship, the preparation step and the calculation are performed. Process and calculate the evaluation value,
In the evaluation step, the evaluation value is used to evaluate the influence of the evaluation target group on the pipe network.

h = r * q * | q | ^0.85 ... Formula (a)
h: Loss head of pipeline
r: Pipe resistance coefficient
q: Pipeline flow rate According to this, pipes are divided into multiple groups, an evaluation target group is determined from these groups, pipes are deleted for each evaluation target group, and the evaluation target group becomes a pipe network. In order to evaluate the impact, the group of pipes that may be disabled at the same time due to valve opening and closing etc. is made into one group, compared to the conventional method of deleting one pipe at a time. The pipe line can be evaluated in a state closer to the state of the pipe network, and a more accurate evaluation result can be obtained.

The second aspect of the present invention is a pipe network comprising a network relationship of an arbitrary number of water sources, a plurality of water demand points, and a plurality of pipelines connected to both ends of the water sources or demand points. When evaluating pipelines that affect the network, the preparation process for performing the evaluation, the calculation process for calculating the evaluation value to be used for the evaluation using the result of the preparation process, and the setting of the evaluation target group An evaluation method of a pipeline for performing a setting process and an evaluation process,
In the preparatory step, the network relationship is established, the pipelines are divided into a plurality of groups, and a calculation formula for calculating the flow rate of each pipeline in the pipeline network is derived based on the network relationship.
In the above calculation step, the flow rate of each pipeline is calculated using the above formula, and the loss head of each pipeline is calculated by substituting the calculated flow rate of each pipeline into the following Hezen-Williams formula (a). The above evaluation value is calculated based on the calculated loss head of each pipeline,
In the setting step, an evaluation target group is determined from each group, and the resistance coefficient in the pipe included in the evaluation target group is set larger than the normal resistance coefficient of the pipe. Change the setting of the inner pipe to a pipe that does not flow easily,
After changing the setting, return to the calculation step, with the resistance coefficient of the pipeline in the evaluation target group increased, calculate the flow rate, loss head and evaluation value of each pipeline,
In the evaluation step, the evaluation value is used to evaluate the influence of the evaluation target group on the pipe network.

h = r * q * | q | ^0.85 ... Formula (a)
h: Loss head of pipeline
r: Pipe resistance coefficient
q: Pipeline flow rate According to this, pipes are divided into multiple groups, and an evaluation target group is determined from these groups, and the resistance coefficient of the pipe line is set larger than the normal resistance coefficient for each evaluation target group. Setting and changing the pipe line in the evaluation target group to a pipe that does not flow easily, and evaluating the effect of the evaluation target group on the pipe network. By grouping multiple pipes into one group, it is possible to evaluate pipes in a state closer to the state of the actual pipe network, compared to the conventional method of deleting pipes one by one, and more accurate Evaluation results can be obtained.

  Even if the pipeline of the evaluation target group is not deleted from the pipe network, the same effect as when the evaluation target group is deleted from the pipe network can be produced in the pipe network. By performing the calculation process on the evaluation value, the evaluation value in the pipe network when the evaluation target group is set can be calculated. Therefore, in the method of deleting the pipeline of the evaluation target group from the pipe network as in the first invention, it is necessary to perform a preparation process such as establishment of a network relationship for the pipe network after deleting the pipe of the evaluation target group. However, it is not related to the value of the pipe resistance by changing the setting of the pipe of the evaluation target group to a pipe that is difficult to flow of water without erasing the pipe of the evaluation target group as in the second invention. The preparation process can be omitted. Therefore, compared with the method of the first invention, it is possible to quickly evaluate the pipeline that affects the pipe network.

The third invention provides initial data such as the head of the water source, the ground height at each demand point, the amount of water taken out from each demand point per unit time, and the amount of water used per person per unit time. And
In the calculation process, based on the value of the head of the water source as the initial data and the ground height of each demand point, and the loss head of the pipeline calculated during the calculation process, the effective head at each demand point is obtained.
The effective water head at each of the above demand points is the evaluation value,
In the evaluation process, when the pipeline in the evaluation target group is shut off, the low pressure target population indicating the population affected by the water shutoff due to the pressure drop is obtained based on the following formula (b),
LDa = Σ (S _i × F _i ) (b)
In the above formula (b),
LDa is the population subject to low pressure in the evaluation group,
S _i is the water supply population set for each demand point, and is a value obtained from the amount of water taken out per unit time from each demand point as initial data and the amount of water used per person per unit time. Yes,
_Fi is a value corresponding to the presence or absence of water breakage at each demand point. When the effective water head at each demand point falls below a predetermined value, it is determined that there is water breakage, and when it is larger than the predetermined value, there is no water breakage. Is determined to be 0.

  According to this, by calculating the low-pressure target population as an evaluation index, the pipeline can be easily evaluated for each group only by comparing the magnitudes of the values. In addition, when the pipes of the evaluation target group are deleted, or when the resistance coefficient of the pipes of the evaluation target group is set to a large value, the order of the size of the low-pressure target population is the majority of the populations affected by water breakage in the pipe network. Therefore, the importance of the pipeline can be determined for each group from this result.

  As described above, according to the present invention, a plurality of pipelines that may be unusable at the same time due to opening and closing of a valve are grouped into one group, so that the conventional pipeline is erased one by one. Thus, the pipeline can be evaluated in a state closer to the actual state of the pipe network, and a more accurate evaluation result can be obtained.

Hereinafter, the pipe line evaluation method according to the first embodiment of the present invention will be described with reference to FIGS. In this evaluation method, detailed description of the same content as in the prior art is omitted.
As shown in FIG. 1, the pipe network is similar to the conventional one because of the network relationship between the water source S1, the plurality of pipelines K1 to K8, and the plurality of nodes N1 to N6 (corresponding to water demand points). It is configured. Further, the initial data given at the time of calculating the pipe network is the same as the initial data shown in FIGS.

  The pipeline evaluation method includes (1) a preparation step for performing an evaluation, (2) a calculation step for calculating an evaluation value used for the above-described evaluation using the result of the preparation step, and (3) an evaluation target group. And (4) an evaluation process for evaluating which important group has a large influence on the entire pipe network.

As shown in FIG. 2, first, (1) the preparation process will be described based on Step 1 (S001) to Step 7 (S007).
As in the prior art, in step 1 (S001), the initial data of the pipe network is read, and in step 2 (S002), the network relation of the pipe network is established. Thereafter, in step 3 (S003), as shown in FIG. 1, the pipes K1 to K8 are divided into a plurality of groups G1 to G4 connected via nodes N1 to N6. Then, the calculation formula which calculates flow volume q (K1)-q (K8) of each pipeline K1-K8 in a pipe network is derived by Step 4 (S004)-Step 7 (S007). In this case, since this is the first calculation performed on a normal (complete state) pipe network, the breadth-priority tree is the same as that shown in FIG. The nonlinear simultaneous equations are the same as those shown in the conventional equation (6), and the Jacobian matrix J is the same as that shown in the conventional equation (9). Note that step 4 (S004) to step 7 (S007) are the same as the conventional step 3 (S003) to step 6 (S006) shown in FIG. 9, and a detailed description thereof will be omitted.

Next, (2) the calculation process will be described based on Step 8 (S008) to Step 15 (S015) in FIG.
The calculation step calculates the flow rates q (K1) to q (K8) of the pipelines K1 to K8 using the calculation formula derived in the preparation step, and calculates the calculated flow rate q (K1 of the pipelines K1 to K8). ) To q (K8) are substituted into the Hazen-Williams equation expressed by Equation 1 above to calculate the loss heads h (K1) to h (K8) of the pipelines K1 to K8. From the heads h (K1) to h (K8) and the values of LWL and ground height given in advance as data, the effective heads P (N1) to P (N6) at the nodes N1 to N6 and the effective head P at the water source S1 (S1) is obtained.

  Since step 8 (S008) to step 15 (S015) of the calculation process are the same as the conventional step 7 (S007) to step 14 (S014) shown in FIG. 9, detailed description thereof is omitted.

Next, (3) the evaluation target group setting process will be described based on step 16 (S016) to step 18 (S018) in FIG.
In step 16 (S016), the first calculation is performed on the normal pipe network without deleting the groups G1 to G4 to be evaluated, and the process directly proceeds to step 17 (S017).

  In step 17 (S017), it is determined whether there is another group to be evaluated. As described above, the first calculation of the pipe network is performed on the pipe network in a normal state without deleting the groups G1 to G4, and each group G1 to G4 must be evaluated next. Since there is a group to be evaluated (hereinafter referred to as an evaluation target group), the process proceeds to step 18 (S018).

  In step 18 (S018), if the evaluation target group is G1 among the groups G1 to G4, the pipelines K4, K5, and K8 of the evaluation target group G1 are deleted from the pipe network as shown in FIG. In this case, it is assumed that the flow in the direction of the pipe K8 is stopped by a valve (not shown) installed at the node N6, and the flow to the pipes K4 and K5 is stopped by valves (not shown) at the nodes N2 and N4. it can. For example, when the pipeline K8 becomes unusable due to an accident or the like, the elimination of the evaluation target group G1 closes the valves and closes the pipelines K4, K5, K8, and at the same time three pipes. This corresponds to a state in which the paths K4, K5, and K8 are unusable.

  When the evaluation target group G1 is deleted from the pipe network in the normal state, the connection relation of the water source S, the node N, and the pipe K after the pipes K4, K5, and K8 are deleted, that is, the network relation of the pipe network is renewed. Therefore, as shown in FIG. 2, the process returns from step 18 (S018) to step 2 (S002).

  Then, for the pipe network in which the pipes K4, K5, and K8 of the evaluation target group G1 have been deleted, a preparatory process such as the construction of the network relation of the pipe network and the search for the width priority tree is performed. A calculation formula for calculating the evaluation value is derived.

That is, in the preparation process, steps 2 to 7 are executed again. FIG.
Shows the result of the breadth-first tree search in the pipe network in which the pipes K4, K5, and K8 of the evaluation target group G1 are deleted. In this case, the fixed flow rate a of the pipelines K1 to K3, K6, K7, and E1 is expressed as in Expression 21.

  As shown in FIG. 3, when the pipes K4, K5, and K8 of the evaluation target group G1 are deleted, no mesh is formed on the pipe network. Therefore, the flow rate of each pipe line is represented by only the take-out water amounts c1, c2, c4 to c6 (constants) as shown in the following equation (22).

  If the mesh is not formed on the pipe network as described above, the Jacobian matrix J is not necessary, so step 6 and step 7 in FIG. 2 are skipped in the preparation process, and further, steps 8 to 14 are performed in the calculation process. Step 15 is performed.

  That is, in step 15, the flow rate q of each pipe line (in this case, the flow rate q (K1) to q (K3), q (K6)) from the taken-out water amount c1 to c6 (constant) based on the relational expression of the above formula 20. , Q (K7)), and the loss head h (in this case, loss head h (K1) to h (K3), h (K6), h (K7)) is obtained from the flow rate q, and each node ( In this case, N1, N2, N4 to N6) and the effective head P of the water source S1 (in this case, P (N1), P (N2), P (N4) to P (N6), P (S1)) are obtained. In addition, since the pipe lines K4, K5, and K8 of the evaluation target group G1 are deleted this time, the effective head P (N3) of the node N3 is 0 m.

Thereafter, in step 16, since the calculation is performed when the pipes K4, K5, and K8 of the group G1 are deleted this time, the pipes K4, K5, and K8 of the group G1 are returned to their original positions.
Thereafter, similarly to the group G1, the groups G2 to G4 are sequentially deleted as the evaluation target groups one by one through the step 17 and the step 18 in FIG.

  For example, next, when the evaluation target group G2 is deleted, as shown in FIG. 2, the process returns from step 18 (S018) to step 2 (S002), and the preparation steps from step 2 to step 7 are executed again, and the evaluation is performed. For the pipe network in which the pipe lines K2 and K3 of the target group G2 are deleted, the preparatory steps such as the construction of the network relation of the pipe network and the search for the width priority tree are performed, and the evaluation value in the pipe network is calculated. A calculation formula for deriving is derived.

  FIG. 4 shows a result of the breadth-first tree search in the pipe network in which the pipes K2 and K3 of the evaluation target group G2 are deleted. In this case, the fixed flow rate a of the pipelines K1, K4 to K8, and E1 is expressed as in Expression 23.

  Further, as shown in FIG. 4, a mesh 1 is formed on the pipe network, and the flow rate q of each pipe line using the mesh 1 is expressed by the following equation (24).

  As a result, the following formula 25 is established for the mesh 1.

  At this time, the formula expressed by Formula 25 is expressed as Formula 26 below from Formula 1.

  In addition, ΔM and F (M) in the above equation 7 are represented by the following equation 27, respectively.

  Furthermore, since the number of meshes formed in the pipe network is one, the Jacobian matrix is represented by a 1 × 1 matrix as shown in the following Expression 28.

  Then, the process proceeds to the calculation process, and Steps 8 to 15 are executed again to obtain the flow rate m1 of the mesh 1, and the pipes K2 and K3 of the evaluation target group G2 are erased based on the flow rate m1. The flow rate q of each pipeline in the net, the loss head h, and the effective head P of each node and the water source S1 are obtained. In this case, the effective head P (N1) of the node N1 is 0 m.

The effective heads P (N1) to P (N6) of the nodes N1 to N6 in the pipe network in the state where the groups G1 to G4 are sequentially deleted as the evaluation target groups as described above are obtained. When there are no more groups to be evaluated, the process proceeds to (4) evaluation process.
(4) In the evaluation process, in step 19 (S019) of FIG. 2, the low pressure target population when each group G1 to G4 is deleted as the evaluation target group is calculated based on the above equation 18. For example, when the group G1 is deleted, the values of F _{1 to} F ₆ are as follows based on the effective heads P (N1) to P (N6) of the nodes N1 to N6 obtained in the calculation steps (S008 to S015). If the situation is as shown in Table 2, the low-pressure target population LDa (G1) when the group G1 is deleted is as shown in the following equation 29. Incidentally, population served _S 1 to S ₆ in each node N1~N6 is the same level as before.

  Further, in the same manner as described above, each of the low-pressure target populations LDa (G2) to LDa (G4) corresponding to the case where the groups G2 to G4 are deleted is calculated. Among each of the low-pressure target populations LDa (G1) to LDa (G4) thus determined, the larger the value, the higher the importance.

  In the first embodiment, since the pipelines K1 to K8 are divided into four groups G1 to G4, a total of four types of low pressure target populations LDa (G1) to LDa (G4) are calculated. Become.

  As described above, in the first embodiment, a plurality of pipelines that may be unusable at the same time due to valve opening / closing or the like are made into one group, and the pipelines are deleted for each group. As a result, it is possible to evaluate pipes in a state closer to the state of the actual pipe network compared to the conventional method of erasing pipes one by one. Evaluation results can be obtained.

Hereinafter, a pipe line evaluation method according to the second embodiment of the present invention will be described with reference to FIG. In this evaluation method, detailed description of the same contents as those in the conventional and the first embodiment described above is omitted.
The pipeline evaluation method includes (1) a preparation process, (2) a calculation process, (3) a setting process for setting an evaluation target group, and (4) an evaluation process. Among these, (1) the preparation step, (2) the calculation step, and (4) the evaluation step have the same contents as in the first embodiment described above. Also shows the pipeline resistance of Kakukanro K1~K8 and _r 1 ~r _8.

  As shown in FIG. 5, first, Step 1 (S001) to Step 7 (S007) are executed in the (1) preparation step. In this case, since this is the first calculation to be performed on a normal pipe network, the breadth-priority tree is the same as that shown in FIG. The nonlinear simultaneous equations are the same as those shown in the conventional equation 6, and the Jacobian matrix J is the same as that shown in the conventional equation 9.

  Thereafter, (2) Step 8 (S008) to Step 15 (S015) are executed in the calculation process, and the effective heads P (N1) to P (N6) at the nodes N1 to N6 with respect to the normal pipe network. Ask for.

Next, (3) the evaluation target group setting process will be described based on Step 16 (S016) to Step 18 (S018).
In step 16 (S016), the calculation performed first is not performed for any of the groups G1 to G4, and is performed on a normal pipe network. Therefore, the process proceeds directly to step 17 (S017). .

  In step 17 (S017), it is determined whether there is another group to be evaluated. As described above, the first calculation of the pipe network is performed on the pipe network in a normal state without deleting the groups G1 to G4, and each group G1 to G4 must be evaluated next. Since there is a group to be evaluated (hereinafter referred to as an evaluation target group), the process proceeds to step 18 (S018).

In step 18 (S018), if the evaluation target group is G1 among the groups G1 to G4, the pipe resistances r ₄ , r ₅ , r _{8 of the} pipes K4, K5, K8 of the evaluation target group G1. Is set sufficiently larger than the normal pipe resistance of these pipes K4, K5, and K8, and the pipes K4, K5, and K8 of the evaluation target group G1 are difficult to flow through. Change the setting to. In this case, it is assumed that the flow in the direction of the pipe K8 is stopped by a valve (not shown) installed at the node N6, and the flow to the pipes K4 and K5 is stopped by valves (not shown) at the nodes N2 and N4. it can. For example, when the pipe line K8 becomes unusable due to an accident or the like, the pipes of the evaluation target group G1 are closed by closing the valves and closing the pipe lines K4, K5, and K8. This corresponds to a state in which the pipe lines K4, K5, and K8 become unusable.

As described above, the pipes K4, K5, and K8 of the evaluation target group G1 are changed to pipes that are difficult to flow of water, and the pipes K4, K5, and K8 of the evaluation target group G1 are blocked. By expressing, the pipes of the evaluation target group G1 from the pipe network without deleting the pipes K4, K5, K8 of the evaluation target group G1 from the pipe network as in the first embodiment described above. The same effect as when K4, K5, and K8 are deleted can be produced in the pipe network. In addition, in this case, the network relationship of the pipe network does not change, and therefore the result of the preparation process performed based on the network relationship does not change. That is, the breadth-first tree is the same as that shown in FIG. 12, the fixed flow rate is the same as that shown in Equation 3, the nonlinear simultaneous equation is the same as that shown in Equation 6, The Jacobian matrix J is the same as that shown in the conventional equation (9). Thereby, when calculating the evaluation value in the pipe network in which the evaluation target group G1 is set, a preparation step (== not related to the values of the pipe resistances r ₄ , r ₅ , r ₈ is performed based on the network relation. Steps 1 to 7) in FIG. 5 can be omitted.

Thereby, when calculating the evaluation value in the pipe network in which the evaluation target group G1 is set, the calculation can be performed from step 8 onward after the calculation results differ depending on the magnitudes of the pipe resistances r ₄ , r ₅ , r _8. it can.

From the above, as shown in FIG. 5, the process returns from step 18 to step 8, and (8) steps 8 to 15 are performed as (2) calculation steps as in the prior art. When the absolute values of f1 (M) and f2 (M) are smaller than the threshold value 10 ⁻⁶ in step 12, the iterative calculation by the Newton-Raphson method is terminated, and the process proceeds to step 15.

  In step 15, the values of the mesh flow rates m1 and m2 used for the current calculation are set as the solution of the nonlinear simultaneous equations shown in the above equation (6). Then, using the values of the mesh flow rates m1 and m2, flow rates q (K1) to q (K8) and loss heads h (K1) to h (K8) in the pipelines K1 to K8 are obtained. Effective heads P (N1) to P (N6) and P (S1) in N1 to N6 and the water source S1 are calculated.

After that, in step 16, since the pipe resistances r ₄ , r ₅ , r ₈ of the pipes K4, K5, K8 of the group G1 to be evaluated are set to be sufficiently larger than normal, this time, The pipe resistances r ₄ , r ₅ , r ₈ of the pipes K4, K5, K8 of the group G1 are returned to normal values.

After that, similarly to the group G1, the groups G2 to G4 are sequentially set as the evaluation target groups through the steps 17 and 18, and the pipe resistance of each evaluation target group is set sufficiently larger than the normal time, The effective heads P (N1) to P (N6) and P (S1) at the nodes N1 to N6 and the water source S1 are calculated. For example, when the group G2 evaluated, at step 18, it evaluates each conduit magnitude of the resistance _r 2, _{r 3} of the target group each conduit G2 K2, K3, each of these conduits K2, K3 normal Is set sufficiently larger than the pipe resistance at the time, and Steps 8 to 15 are performed to calculate the effective heads P (N1) to P (N6) and P (S1) at the nodes N1 to N6 and the water source S1. .

  In this way, the effective heads P (N1) to P (N6) of the nodes N1 to N6 in the pipe network having the groups G1 to G4 as the evaluation target groups are obtained. When there are no more groups to be evaluated, the process proceeds to (4) evaluation process.

(4) In the evaluation process, in step 19, based on the above equation 18, the low pressure target population when each group G1 to G4 is an evaluation target group is calculated. For example, when the evaluation target group is the group G1, F ₁ to F based on the values of the effective heads P (N1) to P (N6) of the nodes N1 to N6 obtained in the calculation steps (S008 to S015). _{Assuming that} the value of ₆ is as shown in Table 3 below, the low-pressure target population LDa (G1) when the group G1 is deleted is as shown in Equation 30 below. Incidentally, population served _S 1 to S ₆ in each node N1~N6 is the same level as before.

  Further, in the same manner as described above, the respective low-pressure target populations LDa (G2) to LDa (G4) corresponding to the case where the groups G2 to G4 are set as the evaluation target groups are sequentially calculated. Among each of the low-pressure target populations LDa (G1) to LDa (G4) thus determined, the larger the value, the higher the importance. In the second embodiment, since the pipelines K1 to K8 are divided into four groups G1 to G4, a total of four types of low-pressure target populations LDa (G1) to LDa (G4) are calculated. Become.

  As described above, in the second embodiment, a plurality of pipelines that may simultaneously become unusable due to valve opening / closing or the like are made into one group, and the pipeline resistance for each group is lower than normal. The importance is set for each group, and the importance of each group is evaluated. By this, the pipes are evaluated in a state closer to the actual state of the pipe network compared to the conventional method of deleting the pipes one by one. And more accurate evaluation results can be obtained.

  Moreover, in this 2nd Embodiment, the evaluation value in the pipe network which set the evaluation object group is calculated by changing the setting of the pipe resistance of the evaluation object group and changing the setting to the pipe where water does not flow easily. When calculating, since the preparatory process (= step 1 to step 7 in FIG. 5) not related to the value of the pipe resistance can be omitted, the pipe network is affected as compared with the method of the first embodiment. Can be quickly evaluated.

  In the said 1st and 2nd embodiment, as shown in FIG. 1, although the water source S1, the nodes N1-N6, and the pipe lines K1-K8 are provided in the pipe network, the number of the water sources S1 may be plural, The number of nodes and pipes is not limited to that shown in FIG. Moreover, although the pipe lines K1-K8 are divided into four groups G1-G4, you may divide into several groups other than four. Further, as shown in FIG. 10, in a complete pipe network, two meshes are formed, but a pipe network in which three or more meshes are formed may be used. When N meshes are formed on the pipe network, the Jacobian matrix J is an N × N matrix. Further, the number of pipe lines belonging to one group may be either plural or single. Furthermore, a pipe line that does not belong to a group may exist in the pipe network.

  Moreover, in the said 1st and 2nd embodiment, as shown in FIG. 1, the pipe lines K1-K8 are connected to the groups G1-G4 of what was connected (continuous) through the nodes N1-N6. In order to be able to evaluate even when a plurality of pipelines that are not connected via the nodes are broken at the same time, a group that includes pipelines that are not connected via the nodes may be included. Good.

In the first and second embodiments, if the effective head at each node is 10 m or less, it is determined that there is water breakage, and F _i = 1. If it is greater than 10 m, it is determined that there is no water breakage. Although F _i = 0, the predetermined value is not limited to a head of 10 m and may be a head other than 10 m.

  In the first and second embodiments, the effective heads P (N1) to P (N6) at the nodes N1 to N6 are used as evaluation values, and these effective heads P (N1) to P (N6) are used. The low-pressure target population LDa is obtained and the obtained low-pressure target population LDa is used as an evaluation index. The effective head of each pipeline K1 to K8 is used as an evaluation value, and the effective head of each of these pipelines K1 to K8 is used. The average pressure change amount is obtained, and the obtained average pressure change amount may be used as the evaluation value.

It is a figure of the complete pipe network formed with the pipe line in the 1st Embodiment of this invention, and shows the state which divided the pipe line into the several group. It is a flowchart which shows the evaluation method of a pipe line. It is the figure of the pipe network which deleted the pipe line of evaluation object group G1. It is a figure of the pipe network which erased the pipe line of evaluation object group G2 similarly. It is a flowchart which shows the evaluation method of the pipe line in the 2nd Embodiment of this invention. It is a figure of the complete state of the pipe network used as the object of the conventional evaluation. It is a chart which shows the initial data given to the water source and node in the pipe network shown in FIG. It is a chart which shows the initial data given to the pipe line in the pipe network shown in FIG. It is a flowchart which shows the evaluation method of the conventional pipeline. It is a figure which shows the state which constructed | assembled the network relationship in a pipe network. It is a chart which shows the data of the pipe line E1 in FIG. It is a figure which shows the search result of the breadth priority tree in the pipe network shown in FIG. It is a figure which shows the mesh in the pipe network shown in FIG. It is a figure which shows the conditional expression of the loss head in the mesh of a pipe network. It is a figure which shows the relationship between LWL in a pipe network, a dynamic water level, a loss head, ground height, and an effective head. It is a figure which shows the state which erase | eliminated the pipe line K2 in the pipe network shown in FIG. It is a figure which shows the search result of the breadth priority tree in the pipe network which deleted the pipe line K2 shown in FIG.

Explanation of symbols

S1 Water sources K1 to K8 Pipe lines N1 to N6 Nodes (water demand points)
G1 to G4 Group q (K1) to q (K8) Flow rate h (K1) to h (K8) of each pipe Loss head P (N1) to P (N6) of each pipe Effective head at each node (evaluation value) )
LDa Low pressure target population r Pipeline resistance (resistance coefficient)
c1~c6 amount of extraction water W per capita and per unit time of water per unit time S _i population served F _i water outage value corresponding to the presence or absence of

Claims (3)

A pipe that has an influence on the pipe network in a pipe network composed of an arbitrary number of water sources, a plurality of water demand points, and a plurality of pipes to which the water sources or demand points are connected at both ends. When evaluating a road, a preparation process for performing an evaluation, a calculation process for calculating an evaluation value to be used for the evaluation using a result of the preparation process, a setting process for setting an evaluation target group, and an evaluation A method for evaluating a pipeline for performing a process,
In the preparatory step, the network relationship is established, the pipelines are divided into a plurality of groups, and a calculation formula for calculating the flow rate of each pipeline in the pipeline network is derived based on the network relationship.
In the above calculation step, the flow rate of each pipeline is calculated using the above formula, and the loss head of each pipeline is calculated by substituting the calculated flow rate of each pipeline into the following Hezen-Williams formula (a). The above evaluation value is calculated based on the calculated loss head of each pipeline,
In the above setting process, the evaluation target group is determined from each group, the pipelines included in the evaluation target group are deleted from the pipe network,
After the pipeline is deleted, the process returns to the preparation step, and a new network relationship is established for the pipeline network from which the pipeline in the evaluation target group has been deleted. Based on the new network relationship, the preparation step and the calculation are performed. Process and calculate the evaluation value,
In the evaluation step, an evaluation method of a pipeline characterized by evaluating an influence of the evaluation target group on a pipe network using the evaluation value.
h = r * q * | q | ^0.85 ... Formula (a)
h: Loss head of pipeline
r: Pipe resistance coefficient
q: Flow rate in the pipeline A pipe that has an influence on the pipe network in a pipe network composed of an arbitrary number of water sources, a plurality of water demand points, and a plurality of pipes to which the water sources or demand points are connected at both ends. When evaluating a road, a preparation process for performing an evaluation, a calculation process for calculating an evaluation value to be used for the evaluation using a result of the preparation process, a setting process for setting an evaluation target group, and an evaluation A method for evaluating a pipeline for performing a process,
In the preparatory step, the network relationship is established, the pipelines are divided into a plurality of groups, and a calculation formula for calculating the flow rate of each pipeline in the pipeline network is derived based on the network relationship.
In the above calculation step, the flow rate of each pipeline is calculated using the above formula, and the loss head of each pipeline is calculated by substituting the calculated flow rate of each pipeline into the following Hezen-Williams formula (a). The above evaluation value is calculated based on the calculated loss head of each pipeline,
In the setting step, an evaluation target group is determined from each group, and the resistance coefficient in the pipe included in the evaluation target group is set larger than the normal resistance coefficient of the pipe. Change the setting of the inner pipe to a pipe that does not flow easily,
After changing the setting, return to the calculation step, with the resistance coefficient of the pipeline in the evaluation target group increased, calculate the flow rate, loss head and evaluation value of each pipeline,
In the evaluation step, an evaluation method of a pipeline characterized by evaluating an influence of the evaluation target group on a pipe network using the evaluation value.
h = r * q * | q | ^0.85 ... Formula (a)
h: Loss head of pipeline
r: Pipe resistance coefficient
q: Flow rate in the pipeline As initial data, the head of the water source, the ground height at each demand point, the amount of water taken out per unit time from each demand point, and the amount of water used per person and per unit time are given.
In the calculation process, based on the value of the head of the water source as the initial data and the ground height of each demand point, and the loss head of the pipeline calculated during the calculation process, the effective head at each demand point is obtained.
The effective water head at each of the above demand points is the evaluation value,
In the evaluation process, when the pipeline in the evaluation target group is shut off, the low pressure target population indicating the population affected by the water shutoff due to the pressure drop is obtained based on the following formula (b),
LDa = Σ (S _i × F _i ) (b)
In the above formula (b),
LDa is the population subject to low pressure in the evaluation group,
S _i is the water supply population set for each demand point, and is a value obtained from the amount of water taken out per unit time from each demand point as initial data and the amount of water used per person per unit time. Yes,
_Fi is a value corresponding to the presence or absence of water breakage at each demand point. When the effective water head at each demand point falls below a predetermined value, it is determined that there is water breakage, and when it is larger than the predetermined value, there is no water breakage. The pipe evaluation method according to claim 1, wherein the evaluation method is set to 0.

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