JP2019078430A - Heat exchanger and manufacturing method of heat exchanger - Google Patents

Abstract

To provide a heat exchanger capable of reducing noise at low cost, and a manufacturing method of the heat exchanger.SOLUTION: A manufacturing method of a heat exchanger comprising a pipe in which a first fluid is circulated and a body in which the pipe is accommodated, and being configured to exchange heat of a second fluid that is circulated inside of the body with the first fluid includes: a first cutoff frequency identification step for identifying a first cutoff frequency that the heat exchanger has; a first temporary value determination step for determining a first temporary value from the first cutoff frequency that is identified in the first cutoff frequency identification step; a first numerical analysis step for calculating a cutoff enabled frequency and a noise reduction amount by performing numerical analysis on multiple first straight pipe groups which are disposed at an interval of the first temporary value that is determined in the first temporary value determination step; and a first interval determination step for determining the first temporary value as a first interval in a case where a deviation between a first cutoff enabled bottom frequency that is a lowest frequency among the cutoff enabled frequencies obtained in the first numerical analysis step and the first cutoff frequency is settled within a predetermined allowable range with respect to the first cutoff frequency.SELECTED DRAWING: Figure 3

Description

  The present disclosure relates to a heat exchanger and a method of manufacturing the heat exchanger.

  In high-speed rotating bodies such as when generating electricity with a gas turbine, especially a micro gas turbine, noise in a high frequency range is generated. A silencer may be installed to reduce noise. Patent Document 1 describes providing a silencer in a hot water boiler.

Japanese Patent Application Laid-Open No. 10-259956

  However, when a silencer is separately provided as a noise countermeasure, there is a problem that the product cost increases.

  In view of the above-described circumstances, the present disclosure aims to provide a heat exchanger and a method of manufacturing the heat exchanger that can reduce noise at low cost.

(1) A method of manufacturing a heat exchanger according to at least one embodiment of the present invention,
A method of manufacturing a heat exchanger, comprising: a pipe through which a first fluid flows; and a body containing the pipe therein, wherein the second fluid flowing through the inside of the body exchanges heat with the first fluid.
The piping is a plurality of first straight pipe portions extending along a direction perpendicular to the flow direction of the second fluid, and the plurality of pipes are arranged at intervals along the flow direction of the second fluid. A plurality of first straight pipe groups each including a first straight pipe portion,
The plurality of first straight pipe groups are arranged at a first interval mutually perpendicular to both the extending direction of the plurality of first straight pipe portions and the direction in which the plurality of first straight pipe portions are arranged. And
The manufacturing method is
A first cutoff frequency identification step of identifying a first cutoff frequency of the heat exchanger;
Assuming that the first cutoff frequency is f1 (Hz), the sound velocity of the sound wave transmitted in the second fluid is c (m / sec), and the first temporary value of the first interval is ST1 (m), the following equation (1)
ST1 = c / f1 (1)
A first temporary value determining step of determining the first temporary value from the first cut-off frequency specified in the first cut-off frequency specifying step;
A numerical analysis is performed on a plurality of first straight pipe groups arranged with the first temporary value determined in the first temporary value determining step open, and a first numerical analysis for obtaining a cuttable frequency and a volume reduction Step and
Of the cuttable frequencies obtained in the first numerical analysis step, the deviation between the lowest cuttable lowest frequency, which is the lowest frequency, and the first cut-off frequency is predetermined with respect to the first cut-off frequency And a first interval determining step of determining the first temporary value as the first interval if it is within the range.

  According to the above method (1), by arranging the plurality of first straight pipe groups at a first interval corresponding to one wavelength of the first cut-off frequency, the first cut-off frequency and the first cut-off frequency Since the function of reflecting the sound wave in the band between the first group of straight pipes is added to the heat exchanger, of the sound waves transmitted to the downstream side of the first group of straight pipes, the first cutoff frequency and the first cutoff frequency Acoustic waves in the accompanying bands can be reduced. Since the sound wave transmitted to the downstream side of the first straight pipe group can be reduced only by adjusting the first interval between the first straight pipe groups, a heat exchanger capable of reducing noise at low cost is manufactured. can do.

(2) In some embodiments, in the method of (1) above,
In the first interval determination step, when a deviation between the first lowest cutoff frequency and the first cutoff frequency exceeds a predetermined allowable range with respect to the first cutoff frequency, the first deviation may be determined based on the deviation. (1) Correcting the temporary value and performing numerical analysis on a plurality of first straight pipe groups arranged with the corrected first temporary value open to obtain a cuttable frequency and a volume reduction; The first interval is determined repeatedly until the value of is within a predetermined allowable range for the first cut-off frequency.

  According to the method of (2) above, even if the deviation between the first lowest cutoff frequency and the first cutoff frequency determined by the above method of (1) is large, the first temporary value is corrected based on the deviation. By repeating the numerical analysis, it is possible to determine the first temporary value that makes the deviation as small as possible, that is, the first interval. Therefore, among the sound waves transmitted to the downstream side of the first group of straight pipes, Sound waves in a band associated with one cutoff frequency and the first cutoff frequency can be reduced.

(3) In some embodiments, in the method of (1) or (2) above,
The piping is a plurality of second straight pipe portions extending along a direction perpendicular to the flow direction of the second fluid, and the pipes are arranged in parallel and spaced apart along the flow direction of the second fluid. A plurality of second straight pipe groups each including a plurality of second straight pipe portions are further provided upstream or downstream of the first straight pipe group in the flow direction of the second fluid,
The plurality of second straight pipe groups are arranged at a second distance from each other in the direction perpendicular to both the extending direction of the plurality of second straight pipe portions and the direction in which the plurality of second straight pipe portions are arranged. And
The manufacturing method is
A second cutoff frequency identification step of identifying a second cutoff frequency which is a second cutoff frequency of the sound wave reduced in the heat exchanger and which is different from the first cutoff frequency;
Assuming that the second cutoff frequency is f2 (Hz) and the second temporary value of the second interval is ST2 (m), the following equation (2)
ST2 = c / f2 (2)
A second temporary value determining step of determining the second temporary value from the second cut-off frequency specified in the second cut-off frequency specifying step;
A second numerical analysis is performed to perform numerical analysis on a plurality of second straight pipe groups disposed with the second temporary value determined in the second temporary value determination step, and to obtain a cuttable frequency and a volume reduction Step and
Among the cuttable frequencies obtained in the second numerical analysis step, a deviation between the second cuttable lowest frequency, which is the lowest frequency, and the second cut off frequency is predetermined to the second cut off frequency. And a second interval determining step of determining the second temporary value as the second interval if it is within the range.

  According to the method of the above (3), by arranging the plurality of second straight pipe groups at a second interval corresponding to one wavelength of the second cutoff frequency, the second cutoff frequency and the second cutoff frequency Since the heat exchanger is further added with the function of reflecting the sound waves in the second straight pipe group between the second straight pipe groups, the first cutoff frequency and the first cutoff of the sound waves transmitted downstream of the second straight pipe group In addition to reducing the sound waves in the band associated with the frequency, it is possible to reduce the sound waves in the band associated with the second cutoff frequency different from the first cutoff frequency and the second cutoff frequency. That is, sound waves in a wide band can be reduced. By adjusting the second distance between the second straight pipe groups as well, it is possible to reduce the sound waves transmitted to the downstream side of the second straight pipe groups, thereby manufacturing a heat exchanger capable of reducing noise at low cost. be able to.

(4) In some embodiments, in the method of (3) above,
In the second interval determination step, when a deviation between the second lowest cutoff frequency and the second cutoff frequency exceeds a predetermined allowable range with respect to the second cutoff frequency, the second deviation is determined based on the deviation. (2) The deviation may be corrected by performing a numerical analysis on a plurality of second straight pipe groups arranged by correcting the two temporary values and opening the corrected second temporary values to obtain a cuttable frequency and a volume reduction The second interval is determined repeatedly until the second interval is within a predetermined allowable range for the second cutoff frequency.

  According to the method of (4) above, even if the deviation between the second lowest cutoff frequency and the second cutoff frequency determined by the above method of (3) is large, the second temporary value is corrected based on the deviation. By repeating the numerical analysis, it is possible to determine the second temporary value, that is, the second interval, in which the deviation is made as small as possible, that is, the second of the sound waves transmitted to the downstream side of the second group of straight pipes Sound waves in a band associated with the second cutoff frequency and the second cutoff frequency can be reduced.

(5) In some embodiments, in any of the methods (1) to (4) above,
The second fluid is an exhaust gas of a combustion turbine having n blades and having a rated rotational speed of R (rpm),
The first cutoff frequency f1 is expressed by the following equation (3)
f1 = nR / 60 ... (3)
Identified by

  According to the above method (5), the generated noise can be reduced at low cost.

(6) A heat exchanger according to at least one embodiment of the present invention,
Piping through which fluid flows,
And a body for receiving the pipe therein, wherein the exhaust gas flowing in the body is heat-exchanged with the fluid,
The piping is a plurality of straight pipe portions extending along a direction perpendicular to the flow direction of the fluid heat-exchanged with the exhaust gas, and arranged in parallel along the flow direction of the fluid at intervals Provided with a plurality of straight pipe groups each including a plurality of straight pipe portions,
The plurality of straight pipe groups are separated from each other in the direction perpendicular to both the direction in which the plurality of straight pipe portions extend and the direction in which the plurality of straight pipe portions are arranged, a distance based on the cutoff frequency of the heat exchanger Be placed open.

  By arranging a plurality of straight pipe groups at intervals corresponding to one wavelength of the cut-off frequency, the function of reflecting the sound wave of the cut-off frequency and the band accompanying the cut-off frequency between the straight pipe groups is added to the heat exchanger Therefore, among the sound waves transmitted to the downstream side of the straight pipe group, it is possible to reduce the cut-off frequency and the sound wave in the band associated with the cut-off frequency. By adjusting the distance between the straight pipe groups only, the sound waves transmitted to the downstream side of the straight pipe groups can be reduced, so noise can be reduced at low cost.

  According to at least one embodiment of the present invention, by arranging a plurality of straight pipe groups at intervals corresponding to one wavelength of the cut-off frequency, the cut-off frequency and sound waves in the band associated with the cut-off frequency Since the function of reflecting between is added to the heat exchanger, it is possible to reduce the sound wave in the band associated with the cutoff frequency and the cutoff frequency among the sound waves transmitted to the downstream side of the straight pipe group. By adjusting the distance between the straight pipe groups only, the sound waves transmitted to the downstream side of the straight pipe groups can be reduced, so noise can be reduced at low cost.

FIG. 1 is a view showing a configuration of a micro gas turbine provided with a heat exchanger according to a first embodiment. It is a schematic sectional drawing which shows the structure of piping provided in the inside of the heat exchanger which concerns on Embodiment 1. FIG. It is a flowchart for demonstrating the manufacturing method of the heat exchanger which concerns on Embodiment 1. FIG. It is a graph which shows the result of FEM analysis of the heat exchanger in the manufacturing method of the heat exchanger concerning Embodiment 1. FIG. It is a schematic sectional drawing which shows the structure of piping provided in the inside of the heat exchanger which concerns on Embodiment 2. FIG.

  Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the scope of the present invention is not limited to the following embodiments. The dimensions, materials, shapes, relative arrangements, and the like of components described in the following embodiments are not intended to limit the scope of the present invention, but merely illustrative examples.

(Embodiment 1)
As shown in FIG. 1, the micro gas turbine 1 burns fuel using the turbine 2 and the compressor 3 connected by the rotating shaft 4 and the compressed air compressed by the compressor 3 and the combustion gas thereof. Heat exchange for recovering heat from exhaust gas by heat exchange between the combustor 5 supplied to the turbine 2 and the compressed air (first fluid) compressed by the compressor 3 and the exhaust gas (second fluid) of the turbine 2 And a generator 7 connected to the compressor 3.

  As shown in FIG. 2, the heat exchanger 6 includes a pipe 10 through which the compressed air flows, and a body 13 accommodating the pipe 10 inside. The pipe 10 is provided with a plurality of straight pipe groups 12 including a plurality of straight pipe portions 11. Each straight pipe portion 11 extends in a direction perpendicular to the flow direction A of the exhaust gas in the body 13. In each group 12 of straight pipes, the straight pipe portions 11 are arranged parallel to each other at intervals SL along the flow direction A. In addition, the straight pipe groups 12 are respectively disposed at an interval L in a direction perpendicular to both the direction in which the straight pipe portions 11 extend and the direction in which the straight pipe portions 11 are arranged. Both of the intervals SL and L are distances between the pipe centers of the straight pipe portion 11.

  The straight pipe portions 11 may be straight tubular pipes separated from each other, or by connecting pipes (not shown) in which the end portions of the straight pipe portions 11 adjacent to each other along the flow direction A are curved in a U shape. The straight pipe groups 12 may be connected to constitute one continuous pipe. No matter what configuration the straight pipe group 12 has, the flow direction of the compressed air flowing in the straight pipe portion 11 and the flow direction A in which the exhaust gas flows in the body 13 may cross or be orthogonal to each other. .

Next, the operation of the micro gas turbine 1 provided with the heat exchanger 6 according to the first embodiment will be described.
As shown in FIG. 1, the combustor 5 burns fuel using the compressed air compressed by the compressor 3. The combustor 5 supplies the combustion gas generated by the fuel combustion to the turbine 2. The combustion gas in the turbine 2 rotates a rotor (not shown). The rotation of the rotor is transmitted to the compressor 3 via the rotating shaft 4, and the compressor 3 compresses the air to generate compressed air. At this time, the generator 7 is driven by the compressor 3 to generate power. The exhaust gas of the turbine 2 and the compressed air compressed by the compressor 3 are heat-exchanged in the heat exchanger 6, the exhaust gas is cooled and then exhausted, and the compressed air is heated and supplied to the combustor 5 Be done.

  In a high-speed rotating body such as when power generation is performed by the micro gas turbine 1, noise in a high frequency range is generated. However, in the first embodiment, the distance L between the straight tube groups 12 in the heat exchanger 6 is made to substantially coincide with one wavelength of a specific frequency, whereby a specific frequency and a band associated with that frequency are obtained. The sound waves can be reflected between the straight pipe portions 11 to reduce the sound waves transmitted to the downstream side of the straight pipe group 12. As a result, the noise caused by the equipment installed upstream of the heat exchanger 6 is reduced in the heat exchanger 6.

Next, a method of manufacturing the heat exchanger 6, in particular, a method of determining the distance L between the straight pipe groups 12 in the heat exchanger 6 will be described based on the flowchart of FIG. 3 with reference to FIGS.
First, the cutoff frequency of the heat exchanger 6 is specified (step S1). Assuming that the turbine 2 has n moving blades and the rated rotational speed of the turbine 2 is R (rpm), the cause of the noise generated in the high-speed rotor such as when the micro gas turbine 1 generates electric power The blade passing frequency f (Hz) is given by the following equation f = nR / 60
Calculated by This blade passing frequency f is taken as the cutoff frequency of the heat exchanger 6.

Then, in order to make the distance L between the straight pipe groups 12 coincide with one wavelength of the blade passing frequency f, the temporary value ST of the distance L is determined by the following equation (step S2).
ST = c / f = c / (nR / 60) = 60c / nR
Here, c is the speed of sound (m / sec) of the sound wave transmitted through the exhaust gas in the body 13.

Next, FEM analysis is performed on the plurality of straight pipe groups 12 arranged with the temporary value ST determined in step S2 open (step S3), and the frequency and the volume reduction that can be cut off in the heat exchanger 6 are obtained. . As an example, assuming that the number of moving blades of the turbine 2 is 25 (n = 25) and the rated rotational speed of the turbine 2 is 3600 rpm (R = 3600), the blade passing frequency f is
f = nR / 60 = 25 × 3600/60 = 1500 Hz
It becomes. Assuming that c = 340 m / sec, the temporary value ST is
ST = c / f = 340/3600 = 0.227 m
It becomes. The results of FEM analysis with ST = 0.227 m are shown in FIG.

As can be seen from FIG. 4, for the sound wave of the frequency of 1587 Hz and a band associated with this frequency, sound reduction is possible although there is a difference in volume reduction for each frequency. Therefore, the lowest frequency in this range of frequencies is defined as the lowest frequency that can be cut off. In FIG. 4, the lowest frequency that can be shut off is 1587 Hz. Here, when the deviation between the minimum cutoff frequency and the cutoff frequency with respect to the cutoff frequency (1500 Hz) is calculated,
(1587-1500) /1500×100=5.8%
It becomes.

  If the allowable range of this deviation is determined in advance to be, for example, within ± 10%, the temporary value ST = 0.227 m is determined as the interval L (step S4) because the result of FIG. 4 is within this range.

If the allowable range of the deviation between the lowest cutoff frequency and the cutoff frequency with respect to the cutoff frequency is previously determined to be, for example, within ± 5% in step S4, the result of FIG. 4 is out of this range. Fix it. In the result of FIG. 4, since the lowest cutoff frequency is higher than the cutoff frequency,
ST = c / f
In consideration of the relationship between ST and f in the equation of (4), the temporary value ST is corrected to be increased in order to reduce the minimum interruptible frequency.

  Assuming that the corrected temporary value is ST '(> ST), FEM analysis is performed again on the plurality of straight pipe groups 12 arranged with the temporary value ST' open. This operation is repeated until the lowest cutoff frequency obtained by the repeated FEM analysis is within the tolerance of ± 5%. As a result, the temporary value ST 'when the lowest cutoff frequency falls within the allowable range of ± 5% is determined as the interval L.

  Thus, by arranging the plurality of straight pipe groups 12 at intervals corresponding to one wavelength of the cut-off frequency of the heat exchanger 6, the sound wave in the band associated with the cut-off frequency and the cut-off frequency can be straight pipe group 12 Since the function of reflecting between the heat exchangers 6 is added, it is possible to reduce the cut-off frequency and the sound wave in the band associated with the cut-off frequency among the sound waves transmitted to the downstream side of the straight pipe group 12. The sound waves transmitted to the downstream side of the straight pipe group 12 can be reduced only by adjusting the distance between the straight pipe groups 12, so noise can be reduced at low cost.

  In the first embodiment, the number of each of the straight pipe portion 11 and the straight pipe group 12 is not limited to the number shown in FIG. 2 and may be appropriately changed according to the heat exchange performance required for the heat exchanger 6 It is possible.

  In the first embodiment, the tolerance range of the deviation between the lowest cutoff frequency and the cutoff frequency with respect to the cutoff frequency is ± 10% and ± 5%, but these are only examples, and the tolerance range can be arbitrarily set.

Second Embodiment
Next, a heat exchanger according to Embodiment 2 and a method of manufacturing the same will be described. The heat exchanger according to the second embodiment is the heat exchanger according to the first embodiment further provided with another plurality of straight pipe groups arranged at an interval different from the interval L. In the second embodiment, the same components as those of the first embodiment are denoted by the same reference numerals, and the detailed description thereof is omitted.

  As shown in FIG. 5, the pipe 10 includes a plurality of first pipe groups 20 including a plurality of first straight pipe groups 12 including a plurality of first straight pipe portions 11 and a plurality of pipes including a plurality of second straight pipe portions 31. And a second pipe group 30 including the second straight pipe group 32. The first tube group 20 is the same as the configuration of the plurality of straight tube groups 12 of the first embodiment, and the plurality of first straight tube portions 11 in each first straight tube group 12 are disposed with an interval SL1 In the one pipe group 20, the plurality of first straight pipe groups 12 are disposed at a first interval L1.

The second pipe group 30 is disposed downstream of the first pipe group 20 in the flow direction A of the exhaust gas. In each second straight pipe group 32, the plurality of second straight pipe portions 31 are disposed at an interval SL2, and in the second pipe group 30, the plurality of second straight pipe groups 32 are disposed at a second distance L2. There is. The spacing SL2 may be the same as or different from the spacing SL1. The second interval L2 is different from the first interval L1, and in the second embodiment, L2> L1. However, depending on the cutoff frequency of the sound wave to be reduced in the second tube group 30, L2 <L1 may be satisfied.
The other configuration is the same as that of the first embodiment.

Next, the operation of the micro gas turbine 1 provided with the heat exchanger 6 according to Embodiment 2 of the present invention will be described.
The operation of generating power in the micro gas turbine 1 is the same as that of the first embodiment. In the second embodiment, in the first tube group 20 having the same configuration as the first embodiment, the pipe 10 further includes the second tube group 30 in addition to the same sound reduction effect as the first embodiment. It is possible to reduce the sound wave of the band other than the band reduced by. In the second embodiment, since L2> L1, it is possible to reduce the sound wave in a band of a lower frequency than the band reduced in the first embodiment.

Next, a method of manufacturing the heat exchanger 6, in particular, a method of determining the first distance L1 between the first straight pipe group 12 and the second space L2 between the second straight pipe group 32 in the heat exchanger 6 is illustrated. A description will be given based on the flowchart of FIG. 4 with reference to FIG.
The method of determining the first interval L1 is the same as that of the first embodiment, and the first interval L1 is determined by steps S1 to S4 in FIG. That is,
The blade passing frequency f1 (Hz), which causes noise generated in high-speed rotating bodies when power is generated by the micro gas turbine 1, is given by the following equation f1 = nR / 60
Calculated by This blade passing frequency f1 is set as a first cut-off frequency cut by the heat exchanger 6 (step S1).

Next, in order to make the first interval L1 between the first group of straight pipes 12 coincide with one wavelength of the blade passing frequency f1, the first temporary value ST1 of the first interval L1 is determined by the following equation (Step S2).
ST1 = c / f1 = c / (nR / 60) = 60 c / nR

  Next, FEM analysis is performed on the plurality of first straight pipe groups 12 arranged with the first temporary value ST1 determined in step S2 open (step S3), and the frequencies that can be cut off by the heat exchanger 6 The volume reduction is determined, and the lowest frequency among the frequencies that can be shut off is taken as the lowest frequency that can be shut off. If the difference between the first lowest cutoff frequency and the first cutoff frequency with respect to the first cutoff frequency falls within a predetermined allowable range, the first temporary value ST1 is determined as the first interval L1 (step S4).

  In step S4, when the difference between the first lowest cutoff frequency and the first cutoff frequency with respect to the first cutoff frequency is out of the allowable range, the first temporary value ST1 is corrected. Assuming that the corrected first temporary value is ST1 ', FEM analysis is performed again on the plurality of first straight pipe groups 12 arranged with the first temporary value ST1' open. This operation is repeated until the first lowest interruptible frequency obtained by the repeated FEM analysis falls within the allowable range. As a result, the first temporary value ST1 'when the first lowest cutoff frequency falls within the allowable range is determined as the first interval L1.

  The method of determining the second interval L2 is also substantially the same as the method of determining the first interval L1. In step S1, the second cutoff frequency f2 is specified in the range of the frequency of the band in which the first tube group 20 does not reduce the noise. In the second embodiment, the second cutoff frequency f2 is specified so that sound waves in a frequency band lower than 1500 Hz which are not reduced by the first tube group 20 can be reduced.

Next, in order to make the second interval L2 between the second straight pipe groups 32 coincide with one wavelength of the second cutoff frequency f2, the second temporary value ST2 of the second interval L2 is set by the following equation It determines (step S2).
ST2 = c / f2

  Next, FEM analysis is performed on the plurality of second straight pipe groups 32 arranged with the second temporary value ST2 determined in step S2 open (step S3), and the frequency that can be shut off in the heat exchanger 6 The volume reduction is determined, and the lowest frequency among the frequencies that can be shut off is taken as the second lowest cutoff frequency. If the difference between the second lowest cutoff frequency and the second cutoff frequency f2 with respect to the second cutoff frequency f2 falls within a predetermined allowable range, the second temporary value ST2 is determined as the second interval L2 (step S4) .

  In step S4, if the difference between the second lowest cutoff frequency f2 and the second lowest cutoff frequency f2 with respect to the second cutoff frequency f2 is out of the allowable range, the second temporary value ST2 is corrected. Assuming that the corrected second temporary value is ST2 ', FEM analysis is performed again on the plurality of second straight pipe groups 32 arranged with the second temporary value ST2' open. This operation is repeated until the second lowest cutoff frequency obtained by the repeated FEM analysis falls within the allowable range. As a result, the second temporary value ST2 'when the second lowest cutoff frequency falls within the allowable range is determined as the second interval L2.

  Thus, the first tube group 20 can reduce the sound wave in the band associated with the first cutoff frequency and the first cutoff frequency, and the second tube group 30 can reduce the second cutoff frequency and the second cutoff frequency different from the first cutoff frequency. Since the sound waves in the band associated with the two cutoff frequencies can be reduced, the sound waves in a wide band can be reduced.

  In the second embodiment, the second pipe group 30 is disposed downstream of the first pipe group 20 in the flow direction A of the exhaust gas, but is disposed upstream of the first pipe group 20 in the flow direction A of the exhaust gas. May be In addition, at least one other third pipe group is provided on at least one of the upstream side or the downstream side of the first pipe group 20 or the upstream side or the downstream side of the second pipe group 30 in the flow direction A of the exhaust gas It is also good. In this case, the method of determining the distance between the plurality of third straight pipe groups of the third pipe group is the same as that of the second pipe group 30.

  In the second embodiment, the number of each of the first straight pipe portion 11 and the second straight pipe portion 31 and the number of the first straight pipe group 12 and the second straight pipe group 32 is not limited to the number shown in FIG. The heat exchanger 6 can be appropriately changed according to the heat exchange performance required for the heat exchanger 6.

  In Embodiments 1 and 2, although the heat exchanger 6 is a heat exchanger for recovering heat from the exhaust gas of the turbine 2 of the micro gas turbine 1, the present invention is not limited to this form. It may be a heat exchanger to recover heat from the turbine of a large gas turbine. Moreover, the present invention can be applied to a heat exchanger for any purpose. For example, in the case of a heat exchanger used in a boiler, the present invention can be applied to reduce the noise generated from the fan.

  Depending on the space L in the first embodiment and the first space L1 and the second space L2 in the second embodiment, the heat exchange performance of the heat exchanger 6 may not be obtained as originally expected. In this case, the straight pipe portion 11 and the first straight pipe portion 11 and the second straight pipe portion 31 may be provided with fins, the shape of the fins may be changed, or the straight pipe portion 11 and the first straight pipe portion 11 and the first The heat exchange performance of the heat exchanger 6 can be complemented by adjusting the number of the two straight pipe portions 31 or the like.

DESCRIPTION OF SYMBOLS 1 Micro gas turbine 2 Turbine 3 Compressor 4 Rotor shaft 5 Combustor 6 Heat exchanger 7 Generator 10 Piping 11 Straight pipe part (1st straight pipe part)
12 straight tube group (1st straight tube group)
13 body 20 first pipe group 30 second pipe group 31 second straight pipe portion 32 second straight pipe group

Claims (6)

A method of manufacturing a heat exchanger, comprising: a pipe through which a first fluid flows; and a body containing the pipe therein, wherein the second fluid flowing through the inside of the body exchanges heat with the first fluid.
The piping is a plurality of first straight pipe portions extending along a direction perpendicular to the flow direction of the second fluid, and the plurality of pipes are arranged at intervals along the flow direction of the second fluid. A plurality of first straight pipe groups each including a first straight pipe portion,
The plurality of first straight pipe groups are arranged at a first interval mutually perpendicular to both the extending direction of the plurality of first straight pipe portions and the direction in which the plurality of first straight pipe portions are arranged. And
The manufacturing method is
A first cutoff frequency identification step of identifying a first cutoff frequency of the heat exchanger;
Assuming that the first cutoff frequency is f1 (Hz), the sound velocity of the sound wave transmitted in the second fluid is c (m / sec), and the first temporary value of the first interval is ST1 (m), the following equation (1)
ST1 = c / f1 (1)
A first temporary value determining step of determining the first temporary value from the first cut-off frequency specified in the first cut-off frequency specifying step;
A numerical analysis is performed on a plurality of first straight pipe groups arranged with the first temporary value determined in the first temporary value determining step open, and a first numerical analysis for obtaining a cuttable frequency and a volume reduction Step and
Of the cuttable frequencies obtained in the first numerical analysis step, the deviation between the lowest cuttable lowest frequency, which is the lowest frequency, and the first cut-off frequency is predetermined with respect to the first cut-off frequency And a first interval determining step of determining the first temporary value as the first interval if it is within the range.   In the first interval determination step, when a deviation between the first lowest cutoff frequency and the first cutoff frequency exceeds a predetermined allowable range with respect to the first cutoff frequency, the first deviation may be determined based on the deviation. (1) Correcting the temporary value and performing numerical analysis on a plurality of first straight pipe groups arranged with the corrected first temporary value open to obtain a cuttable frequency and a volume reduction; The method for manufacturing a heat exchanger according to claim 1, wherein the first interval is determined repeatedly until the value of t falls within a predetermined allowable range for the first cutoff frequency. The piping is a plurality of second straight pipe portions extending along a direction perpendicular to the flow direction of the second fluid, and the pipes are arranged in parallel and spaced apart along the flow direction of the second fluid. A plurality of second straight pipe groups each including a plurality of second straight pipe portions are further provided upstream or downstream of the first straight pipe group in the flow direction of the second fluid,
The plurality of second straight pipe groups are arranged at a second distance from each other in the direction perpendicular to both the extending direction of the plurality of second straight pipe portions and the direction in which the plurality of second straight pipe portions are arranged. And
The manufacturing method is
A second cutoff frequency identification step of identifying a second cutoff frequency which is a second cutoff frequency of the sound wave reduced in the heat exchanger and which is different from the first cutoff frequency;
Assuming that the second cutoff frequency is f2 (Hz) and the second temporary value of the second interval is ST2 (m), the following equation (2)
ST2 = c / f2 (2)
A second temporary value determining step of determining the second temporary value from the second cut-off frequency specified in the second cut-off frequency specifying step;
A second numerical analysis is performed to perform numerical analysis on a plurality of second straight pipe groups disposed with the second temporary value determined in the second temporary value determination step, and to obtain a cuttable frequency and a volume reduction Step and
Among the cuttable frequencies obtained in the second numerical analysis step, a deviation between the second cuttable lowest frequency, which is the lowest frequency, and the second cut off frequency is predetermined to the second cut off frequency. The method of manufacturing a heat exchanger according to claim 1, further comprising: a second interval determining step of determining the second temporary value as the second interval if it is within the range.   In the second interval determination step, when a deviation between the second lowest cutoff frequency and the second cutoff frequency exceeds a predetermined allowable range with respect to the second cutoff frequency, the second deviation is determined based on the deviation. (2) The deviation may be corrected by performing a numerical analysis on a plurality of second straight pipe groups arranged by correcting the two temporary values and opening the corrected second temporary values to obtain a cuttable frequency and a volume reduction The method of manufacturing a heat exchanger according to claim 3, wherein the second interval is determined repeatedly until the second interval is within a predetermined allowable range for the second cutoff frequency. The second fluid is an exhaust gas of a combustion turbine having n blades and having a rated rotational speed of R (rpm),
The first cutoff frequency f1 is expressed by the following equation (3)
f1 = nR / 60 ... (3)
The manufacturing method of the heat exchanger as described in any one of Claims 1-4 specified by these. Piping through which fluid flows,
And a body for receiving the pipe therein, wherein the exhaust gas flowing in the body is heat-exchanged with the fluid,
The piping is a plurality of straight pipe portions extending along a direction perpendicular to the flow direction of the fluid heat-exchanged with the exhaust gas, and arranged in parallel along the flow direction of the fluid at intervals Provided with a plurality of straight pipe groups each including a plurality of straight pipe portions,
The plurality of straight pipe groups are separated from each other in the direction perpendicular to both the direction in which the plurality of straight pipe portions extend and the direction in which the plurality of straight pipe portions are arranged, a distance based on the cutoff frequency of the heat exchanger Heat exchanger opened and placed.