JP6807780B2 - Gas turbine exhaust silencer - Google Patents

Description

The present invention relates to an exhaust silencer of a gas turbine, and more specifically, it is used in a packaged gas turbine facility mainly used for power generation in an emergency, and achieves both miniaturization and sound deadening performance. It is about an exhaust silencer.

Patent Document 1 below describes an invention of a plenum-type silencer in which a partition having a triangular cross section is provided on an inner peripheral surface of a tubular body forming a duct. According to the document, as the action of the invention, "exhaust gas or the like enters the inside from one end of the tubular body and collides with the partition portion, so that the plenum effect and the large portion and the small portion of the passage cross-sectional area are alternately passed. On the other hand, since the cross-sectional shape of the partition is substantially triangular, the exhaust gas can easily flow and the cross-sectional area of the ventilation passage through which the exhaust gas or the like passes suddenly increases as in the conventional case. It does not increase or decrease, but increases or decreases slowly, and as a result, the duct resistance decreases significantly compared to the conventional method. "

In Patent Document 2 below, exhaust muffling of a gas turbine provided with an exhaust port for exhaust from the gas turbine at the lower part of the side surface of the package of the gas turbine and an exhaust port for exhaust at the upper part of the side surface on the opposite side of the package. The vessel is listed.

Jitsufuku No. 6-48096 Jitsufuku No. 5-1634

It cannot be said that these conventional gas turbine silencers have been fully studied in terms of achieving both miniaturization of the silencer package and noise reduction performance.
In recent years, gas turbine equipment used for emergency power generation equipment is configured in a packaged form in which the main part of the equipment is packaged, but it tends to be installed in a narrow space such as the rooftop, middle floor, or basement of a building. Therefore, there is a growing demand for compact gas turbine equipment as a whole.

The muffler that forms part of the gas turbine equipment requires a certain length in the path through which the exhaust gas passes in order to achieve the required muffling performance, and is often in the form of a generally longitudinal shape. It is an important factor that influences the overall size of the equipment. Then, under the restriction of the installation location that there is no margin in the height direction as described above, when this is installed in a vertically long manner, it is often required to reduce the size of the silencer in the height direction. ..

Furthermore, in the muffler of gas turbine equipment, there is a growing demand to arbitrarily set the direction of exhaust gas after muffling. Generally, the exhaust silencer connected to the gas turbine is installed in a vertically long manner as described above, and the exhaust is discharged from the lower side surface and exhausted from the upper side surface. There is a feature that many are seen. When exhausting indoors, it is necessary to connect to a duct that guides the exhaust, and when exhausting outdoors, guide the exhaust laterally and install a hood at the discharge destination, and rainwater is inside the silencer. This is because it is necessary to avoid entering and damaging the sound absorbing material such as rock wool.

An object of the present invention is to provide an exhaust silencer for a gas turbine that achieves both miniaturization and noise reduction performance while considering morphological restrictions in the installation state of the silencer of the conventional gas turbine equipment described above. ..

The gas turbine exhaust silencer according to claim 1 is
A package of a silencer with a rectangular parallelepiped shape and a sound absorbing material on the inner surface,
An exhaust inlet that is provided at the bottom of the side surface of the package and that introduces gas turbine exhaust from the outside lateral direction.
An exhaust exhaust port provided on the upper part of the side surface of the package and exhausting the exhaust of the gas turbine in the external lateral direction,
An upper inward convex portion provided on the inner surface of the package immediately below the exhaust discharge port and having the inner surface protruding in a chevron shape.
A lower inner convex portion provided at a position relatively lower than the upper inner convex portion on a side surface facing the side surface of the package provided with the upper inner convex portion, and the inner surface protruding in a chevron shape. the exhaust muffler of a gas turbine comprising,
An inclined flow path formed between the upper inward convex portion and the lower inward convex portion is upward inside the package so that the exhaust flow is directed toward the side surface opposite to the exhaust discharge port. It is characterized in that the exhaust / exhaust port is inclined so as to approach the side surface facing the side surface provided .

The gas turbine exhaust muffler according to claim 2 is the gas turbine exhaust muffler according to claim 1.
The upper inward convex portion has a downwardly inclined surface in which the direction of the perpendicular line inside the package is directed downward from the horizontal.
The lower inward convex portion has an upwardly inclined surface in which the direction of the perpendicular line inside the package faces upward from the horizontal.
The upward inclined surface substantially parallel-arranged the downward inclined surface is Ru formed Tei an inclined channel with each other.

The gas turbine exhaust muffler according to claim 3 is the gas turbine exhaust muffler according to claim 2.
The flow path width D of the exhaust gas in the inclined flow path is in the range of λ / 2 to λ, where λ is the wavelength of the gas turbine original sound.

The gas turbine exhaust muffler according to claim 4 is the gas turbine exhaust muffler according to any one of claims 1 to 3.
The exhaust exhaust port is provided on a side surface facing the side surface where the exhaust introduction port is provided.

The gas turbine exhaust muffler according to claim 5 is the gas turbine exhaust muffler according to any one of claims 1 to 3.
The exhaust exhaust port is provided on the side surface where the exhaust introduction port is provided.

The gas turbine exhaust muffler according to claim 6 is the gas turbine exhaust muffler according to any one of claims 1 to 5.
An exhaust guide path is connected to the opening of the exhaust exhaust port outside the package.

The exhaust silencer of the gas turbine according to claim 7 is
A package of a silencer in which one of the three sides orthogonal to each other has a rectangular parallelepiped shape longer than the other two sides and has a sound absorbing material on the inner surface,
An exhaust inlet that is provided near one end in the longitudinal direction on a side surface parallel to the longitudinal direction of the package and that introduces gas turbine exhaust from the outside along a direction that intersects the side surface.
An exhaust discharge port provided near the other end in the longitudinal direction on a side surface parallel to the longitudinal direction of the package and exhausting gas turbine exhaust to the outside along a direction intersecting the side surface.
An exhaust discharge port side inward convex portion provided on the inner surface of the package adjacent to the exhaust discharge port and at a position closer to the center in the longitudinal direction of the package and having a mountain-shaped cross section on the inner surface.
The side surface facing the side surface of the package provided with the exhaust discharge port side inward convex portion is provided at a position relatively closer to the exhaust introduction port than the exhaust exhaust port side inward convex portion, and the cross section on the inner surface is chevron. In the exhaust silencer of a gas turbine provided with an inward convex portion on the exhaust introduction port side ,
The package has an inclined flow path formed between the inwardly convex portion on the exhaust discharge port side and the inwardly convex portion on the exhaust introduction port side so that the exhaust flow is directed toward the side surface opposite to the exhaust discharge port. It is characterized in that the inside of the exhaust gas is inclined so as to approach the side surface facing the side surface on which the exhaust gas outlet is provided as it goes upward .

According to the present invention, the package has a rectangular shape, and exhaust is introduced from the lateral direction (direction intersecting the side surface) at the lower portion (one end in the longitudinal direction), and the exhaust is introduced from the lateral direction (direction intersecting the side surface), and the upper portion (the other end in the longitudinal direction) is introduced. In the exhaust silencer of a gas turbine that discharges exhaust in the lateral direction (direction intersecting the side surface) in the section), it is possible to achieve both miniaturization and noise reduction performance of the exhaust silencer, especially in the height direction of the exhaust silencer. The size (longitudinal direction) can be reduced. Further, in addition to reducing the gas turbine noise generated from the gas turbine, the effect of reducing the fluid noise caused by the exhaust flow can also be obtained.

It is a perspective view of the gas turbine which concerns on 1st Embodiment of this invention, and the exhaust silencer connected to the gas turbine. The fraction (a) is a perspective view showing the internal structure by breaking a part of the exhaust silencer according to the first embodiment of the present invention, and the fraction (b) shows the transmission loss in the exhaust silencer. It is a figure which shows the relationship of the frequency, and the sectional figure (c) is a figure which shows typically the vibration of the air in the package of an exhaust silencer. It is a figure which shows the variation of the exhaust silencer which concerns on 1st Embodiment. It is a figure which shows the operation of the exhaust muffler which concerns on 1st Embodiment of this invention, and visualized the flow of the exhaust inside the exhaust muffler by using the analysis software based on the computational fluid dynamics (Computational Fluid Dynamics). It is a streamline diagram. It is a figure which shows the operation of the exhaust silencer which concerns on 1st Embodiment of this invention, and the magnitude of the energy of the exhaust noise inside the exhaust silencer is analyzed by using the analysis software based on the numerical fluid dynamics (Computational Fluid Dynamics). It is a contour diagram visualized by It is a figure which shows the operation of the exhaust silencer which concerns on 2nd Embodiment of this invention, and visualizes the flow of the exhaust inside the exhaust silencer by using the analysis software based on the computational fluid dynamics (Computational Fluid Dynamics). It is a streamline diagram shown in. It is a perspective view which showed the internal structure by breaking a part of the exhaust silencer which concerns on 3rd Embodiment of this invention. It is a figure which shows the operation of the exhaust silencer which concerns on 3rd Embodiment of this invention, and the magnitude of the energy of the exhaust noise inside the exhaust silencer is analyzed by using the analysis software based on the numerical fluid dynamics (Computational Fluid Dynamics). It is a contour diagram visualized by It is a perspective view which showed the internal structure by breaking a part of the exhaust silencer which is a comparative example for each embodiment. It is a figure which shows the operation of the exhaust muffler which is a comparative example, and is the streamline figure which visualized the flow of the exhaust inside the exhaust muffler by using the analysis software based on the numerical fluid dynamics (Computational Fluid Dynamics). .. It is a figure which shows the action of the exhaust muffler which is a comparative example, and the contour which visualized the magnitude of the energy of the exhaust noise inside the exhaust muffler by using the analysis software based on the numerical fluid dynamics (Computational Fluid Dynamics). It is a figure. Figure (a) is a diagram used to examine the noise source in the exhaust silencer, which is a comparative example, and is inside the exhaust silencer using analysis software based on computational fluid dynamics. It is a contour diagram which visualized the flow velocity, and the fractional diagram (b) is also a contour diagram which visualized the magnitude of energy. It is a graph which shows the result of having performed the noise level evaluation test by the actually prototype apparatus about 1st Embodiment and comparative example.

[First Embodiment]
The first embodiment of the present invention will be described with reference to FIGS. 1 to 5.
FIG. 1 shows an outline of the gas turbine equipment according to the first embodiment. This gas turbine facility is an outdoor installation type and includes a gas turbine 1 and an exhaust silencer 2 connected to the exhaust system of the gas turbine 1. The gas turbine 1 is installed on the common pedestal 3 via a vibration isolator. A generator 5 is connected to the output shaft of the gas turbine 1 via a speed reducer 4. The gas turbine 1, the generator 5, and the like are covered with a common enclosure 6. In FIG. 1, a part of the enclosure 6 is broken to show the internal structure.

As shown in FIGS. 1 and 2A, the exhaust silencer 2 according to the first embodiment has a rectangular parallelepiped package 7 that is long in the vertical direction. As can be understood from FIG. 2A showing the cross-sectional structure of the package 7, an exhaust introduction port 8 is provided at the lower part of one side surface of the package 7. The exhaust introduction port 8 is connected to the exhaust port of the gas turbine 1, and the exhaust gas of the gas turbine 1 flowing from the external lateral direction, that is, the direction intersecting the side surface can be introduced into the package 7.

As shown in FIG. 2A, an exhaust diffuser 9 is connected to the exhaust introduction port 8 inside the package 7. The exhaust diffuser 9 prevents damage to the wall surface material such as the sound absorbing material described later due to the exhaust flow directly colliding with the inner wall surface of the package 7. The exhaust diffuser 9 usually has a structure having a cylindrical portion provided with a plurality of slits or holes and a disk-shaped closing portion that closes the end opening of the cylindrical member, and diffuses the exhaust gas in the circumferential direction of the cylinder. Has the function of

As shown in FIG. 2A, an exhaust / exhaust port 10 is provided at the upper part of the side surface of the package 7. In the present embodiment, the exhaust exhaust port 10 is provided on a side surface facing the side surface of the exhaust gas introduction port 8. The exhaust discharge port 10 can discharge the exhaust gas of the gas turbine 1 to the outside of the package 7 in the external lateral direction, that is, in the direction in which the exhaust gas of the gas turbine 1 intersects the side surface.

As shown in FIG. 2A, outside the package 7, an exhaust hood 11 as an exhaust guide path is connected to the opening of the exhaust discharge port 10. The exhaust hood 11 has a bent shape that directs the exhaust discharged in the horizontal direction upward, and although details are not shown, a drain is provided to prevent rainwater from entering the inside of the package 7 of the exhaust silencer 2. Is provided.

In the case of gas turbine equipment installed indoors, an exhaust duct, which is an exhaust guide path in the building, is connected to the outer surface of the package 7 in which the exhaust discharge port 10 is open. The exhaust gas from the exhaust silencer 2 is exhausted from the exhaust exhaust port 10 to the outside through an exhaust duct.

As shown in FIG. 2A, on the inner surface of the package 7, at a position directly below the side surface of the package 7 provided with the exhaust discharge port 10, the inner surface of the package 7 projects inward so as to form a chevron shape. The upper inward convex portion 12 is provided. Further, on the inner surface of the side surface facing the side surface provided with the upper inner convex portion 12, the inner surface of the package 7 is directed inward so as to form a chevron shape at a position relatively lower than the upper inner convex portion 12. A protruding lower inward convex portion 13 is provided.

As shown in FIG. 2A, the upper inward convex portion 12 has two inclined surfaces because it is a chevron convex portion, and the relatively lower surface is referred to as a downward inclined surface 14. .. The downward inclined surface 14 means that the direction of the perpendicular line inside the package 7 is an inclined surface facing downward from the horizontal. Further, since the lower inward convex portion 13 is a chevron convex portion, it has two inclined surfaces, and the relatively upper surface is referred to as an upward inclined surface 15. The upward inclined surface 15 means that the direction of the perpendicular line inside the package 7 is an inclined surface facing upward from the horizontal.

As shown in FIG. 2A, the relatively upper surface of the upper inward convex portion 12 is referred to as an upward inclined surface 16. The upward inclined surface 16 means an inclined surface in which the direction of the perpendicular line inside the package 7 faces upward from the horizontal, as in the case of the upward inclined surface 15.

As shown in FIG. 2A, the downward inclined surface 14 of the upper inward convex portion 12 and the upward inclined surface 15 of the lower inward convex portion 13 are substantially parallel to each other, and the exhaust flow path width. Form an inclined flow path 17 having a constant interval D. The inclined flow path 17 is inclined inside the package 7 so as to approach the side surface opposite to the side surface on which the exhaust discharge port 10 is provided as it goes upward.

Although not shown, a sound absorbing material in which punching metal is arranged on the surface of rock wool is attached to the inner surface of the package 7 including the surfaces of the upper inner convex portion 12 and the lower inner convex portion 13. Depending on the noise level required for the exhaust silencer 2, the installation of the sound absorbing material on the inner surface of the package 7 may be omitted, and the iron plate constituting the main body of the package 7 may be left as it is.

The exhaust silencer 2 of the present embodiment is a sound absorbing duct type silencer in which a sound absorbing material is provided on the inner surface of the package 7. The transmission loss of this type of silencer increases in proportion to the sound absorption coefficient of the sound absorbing material, and as shown in FIG. 2B, the wavelength of the gas turbine original sound (or the wavelength of the sound for which a high sound absorbing effect is desired to be obtained). ) Is λ, the maximum transmission loss can be obtained in the frequency range (c / 2D to c / D, c is the speed of sound) in which the exhaust flow path width of the package 7 is in the range of λ / 2 to λ. That is, the highest muffling effect can be obtained within this range. This is because when the dimensions of the package 7 are equal to λ / 2 and λ, the vibration of the air when the sound wave is transmitted through the package 7 becomes large when the sound absorbing material is stretched, as shown in FIG. 2 (c). is there. As a better example of the present embodiment, the exhaust flow path width D, which is the distance between the downwardly inclined surface 14 and the upwardly inclined surface 15 in the inclined flow path 17, is the wavelength of the original sound of the gas turbine 1 of the present embodiment. When is λ, it is the case where it is set in the range of λ / 2 to λ, and at this time, the highest muffling effect can be obtained. Further, when the wavelength λ of the original sound of the gas turbine 1 is shorter than the size of the package 7, the exhaust flow path is provided by the splitter 20 with the sound absorbing material as in the variation of the first embodiment shown in FIG. Can be divided into the optimum flow path width D. It should be noted that the exhaust muffler is important to have a total muffling effect of gas turbine noise and fluid noise, and the exhaust flow path width D is set to a maximum of 4λ without aiming at optimizing the sound absorption effect at the position of the inclined flow path 17. Even in this case, a good sound deadening effect is obtained in practice.

FIG. 4 is a streamline diagram in which the flow of exhaust inside the exhaust silencer 2 of the present embodiment is visualized using analysis software based on computational fluid dynamics (CFD for short). In the exhaust silencer 2 of the gas turbine equipment as in the present embodiment, the following two points are important for effective muffling.
1) Sufficiently mute the original sound of the gas turbine generated in the gas turbine 1 and guided to the exhaust silencer 2 through the exhaust introduction port 8.
2) Do not generate sound between the exhaust introduction port 8 of the exhaust silencer 2 and the exhaust exhaust port 10 (including the exhaust hood 11 and the exhaust duct).

As described above, the interval D of the inclined flow path 17 is set so that the transmission loss can be obtained according to the frequency component (or the frequency component for which the sound deadening effect is desired) having the highest sound pressure in the gas turbine original sound. The gas turbine 1 includes a compressor and a turbine, and each of the compressor and the turbine generates a gas turbine original sound having a frequency determined by the product of the number of blades and the number of rotations. However, the exhaust silencer 2 of the present embodiment has the same frequency. According to this, the sound of the frequency component having the highest sound pressure can be muted.

As shown in FIG. 4, the exhaust speed is attenuated from the exhaust introduction port 8 through the inclined flow path 17 at the interval D to the exhaust discharge port 10. Further, in the inclined flow path 17 at the interval D, most of the exhaust flow is arranged in the same direction as the inclined flow path 17, and is directed to the side surface direction opposite to the exhaust discharge port 10, and the above transmission. Due to the loss mechanism, the predominant frequency components in the gas turbine original sound are effectively attenuated.

As shown in FIG. 4, the flow of the exhaust gas that has passed through the inclined flow path 17 flows in the direction of the exhaust discharge port 10 while suppressing the speed difference that causes fluid noise, which will be described later, by the action of the upward inclined surface 16. It is in order.

FIG. 5 is a diagram in which the magnitude of the energy of the exhaust noise in the exhaust silencer 2 of the present embodiment is analyzed and visualized by the CFD method. In this analysis, the sound (fluid noise) generated between the exhaust introduction port 8 of the exhaust silencer 2 and the exhaust exhaust port 10 (including the exhaust hood 11 and the exhaust duct) is evaluated by simulation, and this fluid noise is evaluated. Does not contain the components of the gas turbine original sound. According to this example, the exhaust energy is attenuated from the exhaust introduction port 8 through the inclined flow path 17 at the interval D to the exhaust discharge port 10. The noise level near the outlet of the exhaust hood 11 (A in the figure) was about 85 dB, and the noise reduction effect of 10 dB was obtained as compared with the comparative example to be compared later.

In the figure in which the exhaust flow is visualized by using the CFD analysis software shown in FIGS. 4, 6 and 10, the flow velocity is represented by a continuously changing color. That is, in the range from blue having the smallest value to red having the largest value, the flow velocity at each position in the exhaust silencer 2 is indicated by a color that changes continuously or in a plurality of stages like a spectrum of light. However, since the drawings attached to the present application are monochrome, these colors are not expressed, and only the brightness of each color is displayed.

[Second Embodiment]
The exhaust silencer 2a of the second embodiment of the present invention will be described with reference to FIG. 6, which corresponds to FIG. 4 of the first embodiment.
In the first embodiment described above, the upper part of the inner surface of the exhaust silencer 2 and the side opposite to the side where the exhaust exhaust port 10 is provided are the corners of the rectangular parallelepiped package 7. Such a shape is effective for strongly obtaining the effect of the expansion type silencer because the cross-sectional area of the fluid flow path inside the exhaust silencer 2 changes, and is suitable when the gas turbine original sound is loud.

FIG. 6 shows a diagram in which the flow of exhaust gas in the exhaust silencer 2a of the second embodiment is visualized. In the second embodiment, the upper portion of the inner surface of the package 7a of the exhaust silencer 2a, and the side opposite to the side where the exhaust exhaust port 10 is provided, has a curved surface-shaped (R-shaped) guide portion 18. There is. The second embodiment is more effective when fluid noise is a problem.

[Third Embodiment]
The exhaust silencer 2b of the third embodiment will be described with reference to FIGS. 7 and 8.
As shown in FIG. 7, in the third embodiment, the structure in which the exhaust introduction port 8 for introducing the exhaust of the gas turbine 1 from the external lateral direction is provided in the lower part of the side surface of the package 7b of the exhaust silencer 2b is the first embodiment. It is the same as the form. On the other hand, the exhaust discharge port 10 is provided on the upper part of the side surface on the same side surface as the side surface on which the exhaust introduction port 8 is provided.

FIG. 8 is a diagram in which the magnitude of the energy of the exhaust noise in the exhaust silencer 2 of the present embodiment is analyzed and visualized by the CFD method. In this analysis, the sound (fluid noise) generated between the exhaust introduction port 8 of the exhaust silencer 2b and the exhaust exhaust port 10 (including the exhaust hood 11 and the exhaust duct) is evaluated by simulation, and this fluid noise is evaluated. Does not contain the components of the gas turbine original sound. According to this example, the noise level near the outlet of the exhaust hood 11 (B in the figure) was about 85 dB, and the noise reduction effect of 10 dB was obtained as compared with the comparative example to be compared later.

Further, according to the present embodiment, since the exhaust introduction port 8 and the exhaust discharge port 10 are provided on the same side surface of the package 7b, the length in the direction in which the exhaust introduction port 8 and the exhaust discharge port 10 protrude from the package 7b Since the space is smaller than that of the first embodiment and the second embodiment, the installation space can be smaller than these.

[Comparison example]
Although the first to third embodiments have been described above, an example of an exhaust silencer that does not have the characteristics of each of these embodiments will be described below with reference to a “comparative example”.
FIG. 9 shows a partially broken perspective view of the exhaust silencer 20 of the comparative example. In this comparative example, the inner surface shape of the package 27 of the exhaust silencer 20 does not include the upper inward convex portion 12 and the lower inward convex portion 13 as in the respective embodiments, and is the same as the outer surface of the packages 7, 7a and 7b. , It has a flat inner surface shape without unevenness like the inner surface of a rectangular parallelepiped. Then, in order to further exert the sound absorbing effect of the sound absorbing material with respect to the noise from the gas turbine 1, the splitter 21 in which the sound absorbing material is arranged is installed in the flue inside the package 7. The splitter 21 is composed of a plurality of flat plates, and each flat plate is attached between a pair of side surfaces of the package 27 so as to be parallel to the longitudinal direction (vertical direction in the drawing) of the package 27 at equal intervals. There is.

FIG. 10 shows a diagram in which the exhaust flow in the comparative example is visualized by the CFD method.
As shown in FIG. 10, in the flue 70 of the exhaust silencer 20 of the comparative example, most of the exhaust flows only on the right side in the figure, and the flow in this portion is the flow on the left side in the figure of the flue 70. Compared to this, both the flow velocity and the flow velocity difference are large, and the generation of fluid noise is large. Such a state of unevenness in the exhaust flow is clearly different from the state of less unevenness as in the first embodiment shown in FIG. 4 and the second embodiment shown in FIG. Will be easy to understand.

As shown in FIG. 10, even at the bent portion 80 above the flue 70, the exhaust flow cannot bend smoothly due to the inertial force of the exhaust flow, causing a speed difference, resulting in fluid noise. The outbreak is large.

As described above, in the comparative example, the exhaust flow has a low tendency of uniformity and uniformity as a whole, has various directional components, and reaches the exhaust discharge port 90 with a large speed difference, so that the fluid There is noise. While these fluid noises are generated inside the package, the flow of exhaust gas entering the exhaust hood 11 is not rectified as shown in FIG. 9, and therefore, as will be described in detail later. Fluid noise is also generated in the vicinity of the exhaust hood 11, which is considered to be a major cause of the noise source.

FIG. 11 is a diagram in which the magnitude of the exhaust noise energy in the comparative example is analyzed and visualized by the CFD method. In FIG. 5 of the first embodiment, the energy rapidly decreases in the process from the exhaust introduction port 8 to the exhaust discharge port 10, whereas in FIG. 11 of the comparative example, the energy distribution in the package is uneven. Therefore, there is a region where energy is large even near the exhaust / exhaust port 90, which is a noise source. Specifically, in the comparative example, the noise level near the outlet of the exhaust duct 11 (C in the figure) is about 95 dB, which is about 10 dB larger than that of each embodiment.

FIG. 12 is a visualization diagram by CFD used for examining the noise generation mechanism and the noise generation position, which are problems in the exhaust silencer 20 of the comparative example. FIG. 12 (a) is a visualization of the flow velocity of exhaust gas near the upper part of the package of the exhaust silencer 20, the exhaust exhaust port 90, the exhaust duct 11 and the upper part of the exhaust duct 11, and FIG. 12 (b) is a diagram. It is a visualization of the magnitude of the energy of the exhaust noise in the portion corresponding to 12 (a).

Comparing the two figures, it can be observed that the energy of the exhaust noise is large in the two regions S1 and S2 in which the distribution of the flow velocity has a large difference (velocity gradient).
That is, in FIG. 12A, in the region S1 indicated by the substantially circular broken line in the figure, there is a dark portion having a relatively large flow velocity below, while a thin portion having a relatively low flow velocity above this. There is. Further, in the region S2 indicated by the vertically long and long circular broken line in the figure, there is a dark portion where the flow velocity is relatively large, particularly on the right edge, while there is a thin portion where the flow velocity is relatively small on the left side.

As shown in FIG. 12B, the energy of the exhaust noise is large in the regions S1 and S2 where the velocity gradient is generated as described above. In particular, the region S2 is larger than the region S1, and a portion having a particularly large energy is vertically long on the right edge thereof (the portion displayed in black in the figure). This result can be interpreted that fluid noise is caused by the flow of fluid when the flow velocity is high and the flow velocity difference with respect to the surroundings occurs.

As described above with reference to FIG. 10, in the comparative example, since the exhaust flow is not rectified, the flow velocity is also non-uniform. As shown in FIG. 10, below the exhaust exhaust port 90, an exhaust band having a remarkably high flow velocity is formed along the inner wall of the package, and the fast exhaust band forms an exhaust exhaust port 90 and an exhaust duct 11. Through this, it is connected to the outside world above the exhaust duct 11. The fluid noise generated near the outlet of the exhaust duct 11 is released to the outside as it is, which is considered to be a factor of increasing the noise.

[Comparison between the first embodiment and the comparative example]
In order to confirm the effect of the present embodiment, the exhaust silencer 2 according to the first embodiment and the exhaust silencer 20 according to the comparative example were actually prototyped. The size of the package was 1200 mm in the exhaust inflow direction, 1500 mm in the width orthogonal to the depth, and 4000 mm in the height. The exhaust flow path width D in the first embodiment was 700 mm. A sound level meter was installed at a position 1 m horizontally from the opening surface of the exhaust hood 11. An evaluation test was conducted in which the exhaust port of the gas turbine 1 was connected to the exhaust introduction port 8 of each of the exhaust silencers 2 and 20, operated under certain conditions, and the noise was measured with a sound level meter.

FIG. 13 is a graph showing the above-mentioned noise measurement results.
Generally, noise analysis (frequency analysis) is required when evaluating noise, but since the frequency characteristics perceived by the human ear are equal, the octave, which is the pitch at which the frequency ratio is doubled, is used. If the sound pressure level is measured as a reference, it fits the evaluation of the noise felt by humans. In this comparison, with respect to the noise to be measured, the sound pressure of each 1/3 octave band in the frequency range of the audible frequency as shown by the horizontal axis of FIG. 13 and the sound pressure of each band as shown by the vertical axis of FIG. I asked for the level. The octave band is a frequency band (band) in which the upper and lower frequency ratios are one octave around a certain frequency, and the center frequency is called the octave band center frequency, and the octave band is called an octave band. The one divided into 1/3 is called the 1/3 octave band.

As shown in FIG. 13, in the exhaust silencer 2 of the first embodiment, improvement in noise level was observed in almost the entire frequency range. A noise reduction effect of about 2 to 5 dB was obtained in the vicinity of 1000 to 2000 Hz, which corresponds to the region of the gas turbine original sound, and a noise reduction effect of about 10 dB was obtained in the vicinity of 400 Hz, which is greatly affected by fluid noise.

[Features of the present invention and effects of each embodiment]
In the exhaust silencer of a gas turbine, a sound absorbing material or an expansion chamber chamber has been conventionally used in order to reduce the original sound of the gas turbine originating from the gas turbine. As a noise source other than the original noise of the gas turbine, the inventor of the present application has discovered that the fluid noise caused by the exhaust flow has a dominant influence on the noise level near the outlet of the silencer of the gas turbine. did. It was also found that not only the fluid velocity is high, but also fluid noise is generated when the fluid velocity difference occurs locally.

As a result of diligent research based on these discoveries, the inventor of the present application aims to reduce fluid noise by smoothly bending the exhaust flow and reducing the flow velocity difference because the exhaust flow has inertia. We have reached the finding that we can do it.

Further, since the inventor of the present application has a relatively small influence of inertia on the transmission of the original sound of the gas turbine, if a bent portion due to the inner surface of a right-angled box is intentionally provided, the sound absorbing effect of the sound absorbing material and expansion We have also reached the finding that the muffling effect can be further increased by the principle of the type muffler.

The present invention has been made based on the above-mentioned discovery of the inventor of the present application and the knowledge regarding the discovery, and according to the embodiment in which this has been realized, the inside of the upper side is directly below the exhaust discharge port 10 which opens in the lateral direction. By providing the convex portion 12, it is possible to suppress the generation of turbulent flow in the vicinity of the exhaust discharge port 10 and reduce the fluid noise. Further, the exhaust flow can be rectified by the inclined flow path 17 formed by the upper inward convex portion 12 and the lower inward convex portion 13, and the fluid noise can be reduced. Further, by inclining the inclined flow path 17 toward the side surface of the package 7 facing the side surface provided with the exhaust exhaust port 10, the noise of the gas turbine 1 originating from the gas turbine 1 is generated by the exhaust exhaust port 10. Noise can be reduced by reducing the ratio of direct direction to the side.

Furthermore, according to the above embodiment, in the exhaust silencer 2 of the gas turbine 1 having the rectangular package 7, receiving the exhaust from the lateral direction and discharging the exhaust in the lateral direction, particularly the height of the silencer. When there is a strong demand for reduction of the exhaust gas, it is possible to obtain both a miniaturization of the exhaust silencer 2 and a noise reduction performance, which is an important effect in practical use.

In the embodiment described above, the rectangular parallelepiped package 7 of the exhaust silencer 2 is arranged in a vertically long form, but the effect is the same even when the rectangular parallelepiped package 7 is arranged in a horizontally long form. That is, the rectangular parallelepiped package 7 is arranged so that the longest side is parallel to the horizontal direction, and the exhaust is introduced from the vertical direction with respect to the package 7 and discharged from the vertical direction. However, the same muffling effect as that of the embodiment can be obtained.

1 ... Gas turbine 2,2a, 2b ... Exhaust silencer 7,7a, 7b ... Package 8 ... Exhaust introduction port 10 ... Exhaust exhaust port 12 ... Upper inward convex part 13 ... Lower inward convex part 14 ... Downward inclined surface 15 … Upward inclined surface 17… Inclined flow path 20… Exhaust silencer of comparative example

Claims (7)

A package of a silencer with a rectangular parallelepiped shape and a sound absorbing material on the inner surface,
An exhaust inlet that is provided at the bottom of the side surface of the package and that introduces gas turbine exhaust from the outside lateral direction.
An exhaust exhaust port provided on the upper part of the side surface of the package and exhausting the exhaust of the gas turbine in the external lateral direction,
An upper inward convex portion provided on the inner surface of the package immediately below the exhaust discharge port and having the inner surface protruding in a chevron shape.
A lower inner convex portion provided at a position relatively lower than the upper inner convex portion on a side surface facing the side surface of the package provided with the upper inner convex portion, and the inner surface protruding in a chevron shape. the exhaust muffler of a gas turbine comprising,
An inclined flow path formed between the upper inward convex portion and the lower inward convex portion is upward inside the package so that the exhaust flow is directed toward the side surface opposite to the exhaust discharge port. An exhaust silencer for a gas turbine that is inclined so as to approach a side surface facing the side surface provided with the exhaust exhaust port toward the direction . The upper inward convex portion has a downwardly inclined surface in which the direction of the perpendicular line inside the package is directed downward from the horizontal.
The lower inward convex portion has an upwardly inclined surface in which the direction of the perpendicular line inside the package faces upward from the horizontal.
Exhaust silencer of a gas turbine according to claim 1, wherein the upward inclined surface substantially parallel-arranged the downward inclined surface forms an inclined channel with each other. The exhaust gas silencer according to claim 2, wherein the exhaust flow path width D in the inclined flow path is in the range of λ / 2 to λ, where λ is the wavelength of the gas turbine original sound. The exhaust silencer for a gas turbine according to any one of claims 1 to 3, wherein the exhaust exhaust port is provided on a side surface facing the side surface where the exhaust introduction port is provided. The exhaust silencer for a gas turbine according to any one of claims 1 to 3, wherein the exhaust exhaust port is provided on a side surface provided with the exhaust introduction port. The exhaust silencer for a gas turbine according to any one of claims 1 to 5, wherein an exhaust guide path is connected to an opening of the exhaust exhaust port outside the package. A package of a silencer in which one of the three sides orthogonal to each other has a rectangular parallelepiped shape longer than the other two sides and has a sound absorbing material on the inner surface,
An exhaust inlet that is provided near one end in the longitudinal direction on a side surface parallel to the longitudinal direction of the package and that introduces gas turbine exhaust from the outside along a direction that intersects the side surface.
An exhaust discharge port provided near the other end in the longitudinal direction on a side surface parallel to the longitudinal direction of the package and exhausting gas turbine exhaust to the outside along a direction intersecting the side surface.
An exhaust discharge port side inward convex portion provided on the inner surface of the package adjacent to the exhaust discharge port and at a position closer to the center in the longitudinal direction of the package and having a mountain-shaped cross section on the inner surface.
The side surface facing the side surface of the package provided with the exhaust discharge port side inward convex portion is provided at a position relatively closer to the exhaust introduction port than the exhaust exhaust port side inward convex portion, and the cross section on the inner surface is chevron. In the exhaust silencer of a gas turbine provided with an inward convex portion on the exhaust introduction port side ,
The package has an inclined flow path formed between the inwardly convex portion on the exhaust discharge port side and the inwardly convex portion on the exhaust introduction port side so that the exhaust flow is directed toward the side surface opposite to the exhaust discharge port. An exhaust silencer for a gas turbine that is inclined so as to approach a side surface opposite to a side surface provided with the exhaust exhaust port as it goes upward .