JPS601572B2 - Circulation water tank for flow test - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a circulating water tank for hydrodynamic testing for observing and measuring various hydrodynamic phenomena related to ships, marine structures, fishing nets, etc. using scale models for testing. This is related.

The hydrodynamic test tank includes a so-called towing tank in which the test model is towed at a predetermined speed in a stationary fluid stored in a long pool, and a measurement section (observation section) installed in a part of the circulation channel. A so-called recirculation water tank is a type in which a test model is fixed to a measurement section (in this specification, the name will be unified as a measurement section) and the fluid is circulated in a circulation channel so that the fluid flows to the measurement section at a predetermined speed. There is.

The former has the advantage of being able to perform highly accurate tests with almost no fluid turbulence, but the equipment is extremely large and expensive, and the test time is not long enough due to the finite length. Alternatively, there are various disadvantages such as extremely low test efficiency because it takes a very long time for the fluid to completely stand still after the test. On the other hand, the latter type of circulating water tank requires much smaller and cheaper equipment, and since the model is fixed and the fluid flows around it, the test time can be extended as long as you like. , the turbulence in the fluid after the test disappears in a very short time, so
It has the advantage of being able to conduct tests extremely efficiently, and the usefulness of this circulating water tank has been gradually recognized, especially in recent years, where, for example, extremely large-scale systematic tests are required to decide on a single ship type. Research on improvements in this regard is being actively conducted.

The only and most significant drawback of the circulating water tank is that it is extremely difficult to obtain a steady flow with a constant axial velocity and no rotation in the measuring section.

To solve this problem, various methods of stabilizing the flow have been considered, such as rectifying plates, corner vanes, honeycombs, punched metal, and surface flow accelerators, but these methods have achieved almost the necessary and sufficient results in making the axial velocity component uniform. It is being However, before the circulating fluid is accelerated by the flow velocity generator and reaches the measuring section, the circumferential velocity may decrease due to friction between the circulating fluid and the inner wall of the circulation channel, and the stroke between the inside and outside of the corner of the circulation channel may occur. Although this is thought to be caused by the difference, the circulating fluid inevitably flows with a pair of left and right outer rotations when viewed from the cross section of the flow path. An effective means for eliminating this pair of left and right outer rotational flows has not yet been found. In view of the above-mentioned circumstances, the present invention aims to improve the recirculation water tank so as to be able to obtain a steady flow without the above-mentioned outer rotation in the measurement section thereof, and has the following features: The purpose of this project is to enable various hydrodynamic tests that require strict accuracy to be performed using a circulating water tank with extremely high test efficiency.

To achieve the above object, the recirculation water tank for flow test according to the present invention is a recirculation water tank for flow power test which is provided with a flow velocity generating device for circulating fluid in a circulation channel having a measuring section. In order to cancel the pair of left and right outer rotational flows that are originally formed between the flow velocity generator and the measurement section, a device is provided that applies a pair of left and right inner rotational forces in advance to the flow to be accelerated by the flow velocity generator. It has the characteristics of:

The functions and effects exhibited by the above characteristic configuration are as follows.

In other words, since a pair of left and right inner rotational flows are formed in advance in the accelerated flow immediately after the flow velocity generator, the pair of left and right rotational flows that are originally supposed to be generated between the flow velocity generator and the measuring section are created in advance. This means that the external rotational flow can be effectively canceled out, making it possible to improve the circulating flow water tank to obtain a steady flow without rotation in the measuring section.

As a result, various hydrodynamic tests that require strict accuracy can now be conducted in a circulation tank with extremely high test efficiency, without the need for a towed tank, and sufficient results can be obtained.

Embodiments of the present invention will be described below with reference to the drawings. The diagram is
Base 3 erected on the ground 2...Circulation flow path 1 on top
It shows a so-called vertical circulation type recirculation water tank, which is made by reloading the water tank vertically.

A measuring section 4 having a free water surface 5 is disposed in the upper horizontal part of the circulation channel 1, and observation windows 6 are provided on the side and bottom walls of the measuring section 4. is provided.

On the other hand, on the lower upstream side of the circulation channel 1, a flow velocity generator 8 is provided.
A pair of left and right inner rollers 7, 7, which have both the role of a rotational force applying device A and a pair of left and right inner rotation force applying devices A, are arranged in parallel in the horizontal direction. Due to the pair of left and right inward rotational forces generated by 7, 7, the accelerated flow immediately after the flow velocity generating device 8 forms a pair of left and right inward rotational flows when viewed from the cross section of the circulation channel 1, as shown in FIG. It is configured.

The pair of left and right inflators 7, 7 are disposed within ducts 9, 9, each having a relatively small magnification ratio, and are driven by separate motors 10, 10, respectively. Note that L II...... is a corner vane, 1
Reference numeral 2 denotes a punched metal, 13 a honeycomb, and 14 a surface flow accelerator, which are configured so that the axial velocity component in the measuring section 4 is made uniform by the cooperation of the effects of these rectifiers.

According to the above configuration, since a pair of left and right inward rotating forces are applied in advance to the accelerated flow immediately after the flow velocity generating device 8 to form a pair of left and right inwardly rotating accelerated flows, the measuring section 4, it is possible to effectively cancel the above-mentioned pair of left and right outer rotational flows that are originally generated during the period of time, and it is possible to obtain a steady flow without rotation in the measuring section 4. .

Moreover, the device A for previously forming the pair of left and right inwardly rotating flows as described above is not constructed using any special device, but is constructed by riding on the invera 7 that should originally be used as the flow velocity generating device 8. Therefore, it can be extremely advantageous in terms of cost.

Furthermore, by arranging the pair of left and right inflators 7, 7 in parallel in the horizontal direction, the enlargement ratio of the ducts 9, 9 is made as small as possible to effectively prevent fluid separation on the inner wall surfaces of the ducts 9, 9. In addition, since the width of the flow path can be made large, there is also the advantage that the measurement section 4 can be made wide and the influence of side walls during measurement can be significantly reduced. Furthermore, the pair of rollers 7, 7 may be driven by one motor, but as in this embodiment, separate motors lo, 101 are used, respectively.
If the rollers are driven in this manner, it is convenient because the optimum rotational speed can be set separately to absorb manufacturing errors of the rollers 7, 7. Note that the configuration of the pair of left and right inner rotating force applying devices A or the flow velocity generating device 8 is not limited to the configuration of the pair of left and right inner rotating inverters 7, 7 as mentioned above, but for example, Various modifications such as a combination of a pair of inner rotating fans are possible, and in short, the accelerated flow immediately after the flow velocity generating device 8 may form a pair of left and right inner rotating flows.

And, such a pair of left and right inward rotational force applying devices A
Needless to say, this method is applicable not only to vertical circulation type recirculation water tanks but also to horizontal circulation type recirculation water tanks.

In summary, the recirculation water tank for fluid force testing according to the present invention should cancel the pair of left and right outer rotational flows that are formed during the circulating fluid from the flow velocity generator 8 to the measuring section 4.
It is characterized in that a device A is provided in advance to apply a pair of left and right inward rotational forces to the flow to be accelerated by the flow velocity generating device 8.

In other words, as described in detail in the embodiment, since a pair of left and right inner rotational flows are formed in advance immediately after the flow velocity generator 8, the flow is originally generated between the flow velocity generator 8 and the measuring section 4. It is possible to effectively cancel out the pair of left and right outer rotating flows as described above, and it has been possible to improve the circulation water tank in which a steady flow without rotation can be obtained in the measuring section 4. As a result, various hydrodynamic tests that require strict accuracy can now be conducted in a circulation tank with extremely high test efficiency, without the need for a towed tank, and sufficient results can be obtained.

[Brief explanation of drawings]

The drawings show an embodiment of the recirculation water tank for hydrodynamic testing according to the present invention, and FIG. 1 is a partially cutaway side view, FIG. 2 is a partially cutaway enlarged plan view of the main part, and FIG. 3 is a partially cutaway side view of the main part. FIG. 3 is a sectional view taken along line PP in FIG. 2; 1...Circulation flow path, 4...Measurement section, 7...
・Inner rotation roller, 8...Flow velocity generator, 9.
...Duct, 10...Motor, A...
...A pair of left and right internal rotational force applying devices. Figure 1 Figure 2 Figure 3

Claims (1)

[Scope of Claims] 1. A recirculation water tank for fluid force testing, which is provided with a flow rate generator 8 for circulating fluid in a circulation channel 1 having a measuring section 4, wherein the circulating fluid is connected to the flow rate generator 8. From measurement section 4
In order to cancel the pair of left and right outer rotational flows that are originally formed during the process, a device A is provided that applies a pair of left and right inner rotational forces to the flow accelerated by the flow velocity generating device 8 in advance. Circulation water tank for hydrodynamic testing. 2. The pair of left and right internal rotational force applying devices A are configured by a pair of left and right internal rotational impellers 7, 7 which are arranged horizontally in parallel with the flow velocity generating device 8, so that the flow velocity generating device 8 itself The circulation water tank according to claim 1, wherein the circulating water tank is configured to form an accelerated flow having a pair of left and right inward rotational forces. 3. The recirculation water tank according to claim 2, wherein the pair of left and right inner impellers 7, 7 are arranged in ducts 9, 9, respectively, which are constructed separately. 4. The circulation water tank according to claim 3, wherein the pair of left and right inner impellers 7, 7 are driven by separate motors 10, 10, respectively.