JP2017194223A - Heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat exchanger capable of suppressing increase of a manufacturing cost of a heat exchanger and preventing occurrence of can noise.SOLUTION: A heat exchanger 1 includes a gas duct 2 that an internal space 3 in which heat source gas G circulates, and a heat transfer pipe group 4 arranged in the internal space 3 and having a plurality of heat transfer pipes 40 arrayed in a flow direction Y of the heat source gas G and in a width direction X orthogonal to the flow direction Y. The gas duct 2 includes a width dimension change part 20 whose dimension in the width direction X changes to the flow direction Y. At least a part of the width dimension change part 20 is arranged in the width direction X outside the heat transfer pipe group 4.SELECTED DRAWING: Figure 1

Description

  The present invention provides a heat exchange device comprising a gas duct through which heat source gas flows in an internal space, and a heat transfer tube group having a plurality of heat transfer tubes arranged in the internal space and arranged in the flow direction and the duct width direction of the heat source gas, respectively. About.

  In a boiler for thermal power generation, a boiler that collects plant exhaust heat and gas turbine exhaust heat (exhaust heat recovery boiler), a heat exchange device in which a heat transfer tube group is arranged in a duct through which high-temperature gas flows is used. The heat transfer tube group includes a plurality of heat transfer tubes arranged in a gas flow direction and a duct width direction (a direction orthogonal to the gas flow direction, hereinafter also referred to as “width direction”).

In such a heat exchange device, standing waves are generated in the duct width direction, and Karman vortices are generated on the downstream side of the heat transfer tube when the high-temperature gas passes through the heat transfer tube. When the frequency of the standing wave coincides with the generation frequency of the Karman vortex, a resonance phenomenon occurs and self-excited sound is generated. This phenomenon is called canning.
The main technologies for preventing the occurrence of canning are: (1) Technology for detuning the frequency of standing waves in the duct width direction and the frequency of Karman vortex generation (hereinafter referred to as “known technology 1”), (2) There is a technique for preventing a standing wave from being generated in the duct width direction (hereinafter referred to as “known technique 2”).
Generally known technique 1 is generally employed because of its simplicity. Specifically, in the known technique 1, an anti-vibration baffle extending in the gas flow direction is provided in the duct, and the standing wave frequency and the Karman vortex are generated by modulating the standing wave frequency to a higher level. The frequency is detuned.

As the known technique 2, for example, there are techniques disclosed in Patent Document 1 and Patent Document 2. Hereinafter, the techniques disclosed in Patent Document 1 and Patent Document 2 will be described. For reference, the symbols used in Patent Document 1 and Patent Document 2 are shown in parentheses.
In the technique disclosed in Patent Document 1, the sound absorbing material (9) is attached to the inner wall portion of the heat exchanger body (1) to make it difficult for the standing wave (8) to be formed (page 3, item 14-19). Row, see Fig. 1).
In the technique disclosed in Patent Document 2, holes (3) are provided on the wall surface of the duct to form a resonance cavity (4). By providing a large number of resonance cavities (4), vibration and noise of the heat exchanger can be reduced. (Refer to the claims of utility model registration, Fig. 1a, Fig. 1b, etc.).

Microfilm of Japanese Utility Model No. 63-123492 (Japanese Utility Model Application No. 02-045363) No. 02-029434

  However, since the generation frequency of the Karman vortex changes in proportion to the flow velocity of the hot gas, in the known technique 1 using the anti-vibration baffle, in order to prevent even higher-order resonance phenomenon, the frequency of the standing wave is changed to the Karman vortex. Must be higher than the maximum generation frequency. For this reason, it is necessary to provide a plurality of anti-vibration baffles in the duct width direction, and there is a problem that the cost increase associated with the installation of the anti-vibration baffles is large.

  In addition, the techniques disclosed in Patent Documents 1 and 2 illustrating the known technique 2 are actually difficult to use. That is, in the technique disclosed in Patent Document 1, since the inside of the heat exchanger body (1) is in a harsh atmosphere in which the high-temperature working fluid (4) flows at a high speed, the sound absorbing material (9) deteriorates early. Therefore, in the technique disclosed in Patent Document 2, since the temperature difference between the inside and outside of the duct is large, deformation or cracking due to the difference in thermal elongation occurs in the resonant cavity (4) formed on the wall surface of the duct. In reality, it is difficult to use.

  An object of the present invention is to provide a heat exchange device that can prevent the occurrence of canning while suppressing an increase in manufacturing cost of the heat exchange device.

  (1) In order to achieve the above object, a heat exchange device according to the present invention includes a gas duct through which heat source gas flows in an internal space, a flow direction of the heat source gas, and a flow direction, which are disposed in the internal space. In the heat exchange device comprising a heat transfer tube group having a plurality of heat transfer tubes arranged in the orthogonal width direction, the gas duct has a width dimension changing portion in which the dimension in the width direction is changed with respect to the flow direction. The width dimension changing portion is characterized in that at least a part thereof is disposed on the outer side in the width direction of the heat transfer tube group.

  (2) It is preferable that the said width dimension change part is located after the upstream end of the said heat exchanger tube arrange | positioned in the 3rd step | paragraph from the said flow direction upstream.

  (3) It is preferable that the said width dimension change part is provided with the expansion part which the dimension of the said width direction expands as it becomes the said flow direction downstream.

  (4) It is preferable that the said width dimension change part is equipped with the reduction | decrease part to which the dimension of the said width direction shrink | contracts in the said flow direction downstream of the said expansion part as it becomes the said flow direction downstream.

  (5) It is preferable that a perforated plate extending along the flow direction is provided outside the heat transfer tube group in the width direction.

  (6) It is preferable that the said width dimension change part is equipped with the reduction part to which the dimension of the said width direction reduces as it becomes the said flow direction downstream.

  (7) It is preferable that the said width dimension change part is equipped with the expansion part which the dimension of the said width direction expands toward the said flow direction downstream in the said flow direction downstream of the said reduction | decrease part.

  (8) It is preferable that the said width dimension change part changes the dimension of the said width direction in the both sides in the said width direction of the said heat exchanger tube group.

  (9) It is preferable that the width dimension change part changes the dimension of the width direction only on one side in the width direction of the heat transfer tube group.

When the duct width is constant, the frequency of the standing wave is also constant, so the standing wave is strengthened as it goes downstream. By changing the width, the frequency of the standing wave also changes with respect to the flow direction, and the strength of the frequency component of the standing wave can be dispersed and reduced, thereby substantially reducing the occurrence of the standing wave in the duct width direction. Can be suppressed.
According to the present invention, it is possible to prevent the occurrence of the squealing by a simple configuration in which the duct width changing portion is provided as described above. Therefore, it is possible to prevent the occurrence of the squealing while suppressing an increase in the manufacturing cost of the heat exchange device.

It is sectional drawing by typical plane view which shows the structure of the heat exchange apparatus of 1st Embodiment of this invention. It is sectional drawing by typical planar view which shows the structure of the heat exchange apparatus of the modification of 1st Embodiment of this invention. A graph in which the horizontal axis is the frequency [Hz] and the vertical axis is the sound pressure level [dB], and the measurement result of the sound pressure level is plotted in the case where the duct width is constant. The sound pressure level in the second heat transfer tube, the broken line indicates the sound pressure level in the third heat transfer tube, and the solid line indicates the sound pressure level in the fourth heat transfer tube. It is sectional drawing by typical plane view which shows the structure of the heat exchange apparatus of 2nd Embodiment of this invention. It is sectional drawing by typical planar view which shows the structure of the heat exchange apparatus of the modification of this invention.

Embodiments of the present invention will be described below with reference to the drawings.
The embodiment described below is merely an example, and there is no intention of excluding various modifications and technical applications that are not explicitly described in the following embodiment. Each configuration of the following embodiments can be implemented with various modifications without departing from the gist thereof, and can be selected or combined as appropriate.

In the present embodiment, an example in which the present invention is applied to a heat exchange device provided in an exhaust heat recovery boiler (hereinafter referred to as “HRSG”) will be described.
In the following description, when “upstream” and “front” are described without any special description, they indicate the upstream in the flow of the combustion exhaust gas (heat source gas) G, and “downstream” and “rear” without any special description. When it describes, it shall point to the downstream in the flow of the combustion exhaust gas G.
The direction along the flow direction of the combustion exhaust gas G is the front-rear direction Y, the horizontal direction orthogonal to the front-rear direction Y is the duct width direction (hereinafter also referred to as “lateral direction” or “width direction”) X, and the duct in the width direction X The direction away from the second center line L0 will be described as the outside or the outside.
Further, the left and right are determined based on the flow direction of the exhaust gas G.

[1. First Embodiment]
[1-1. Constitution]
The heat exchange apparatus 1 of this embodiment is demonstrated with reference to FIG.
FIG. 1 is a schematic cross-sectional view showing the configuration of the heat exchange device 1 of the present embodiment.
As shown in FIG. 1, the heat exchange device 1 includes a gas duct 2 and a heat transfer tube group 4 arranged in an internal space (hereinafter also referred to as “duct internal space”) 3 of the gas duct 2.
An exhaust gas supply duct 100 is connected to the upstream side (inlet side) of the gas duct 2, and an exhaust gas exhaust duct 101 is connected to the downstream side (outlet side) of the gas duct 2, and the exhaust gas G passes through the internal space 3 of the gas duct 2. Circulates in the direction indicated by the white arrow.
In the present embodiment, the heat transfer tube group 4 is configured by arranging a plurality of heat transfer tubes 40 extending in the vertical direction (a direction orthogonal to the paper surface of FIG. 1) in the front-rear and left-right directions. Are of the same specification (same inner diameter, same outer diameter, same material). Water (heated fluid) is supplied to each heat transfer tube 40, and this water is heated by the exhaust gas G in the process of flowing through the heat transfer tube 40 and becomes steam (or a two-phase flow in which water and steam are mixed).

  Hereinafter, the arrangement of the heat transfer tubes 40 having the same axial center line CL when viewed from the front-rear direction Y is referred to as “row”, and the arrangement of the axial center lines CL when viewed from the lateral direction X is referred to as “stage”. Call. In the present embodiment, the heat transfer tubes 40 are arranged in 19 rows × 5 rows by a staggered arrangement shifted by half a pitch in the front, rear, left, and right directions. In the following description, the first column from the right, the second column,..., The 19th column, and the first row (from the upstream), the second row,.

The gas duct 2 includes a duct width changing portion 20 in which the dimension in the width direction X (hereinafter referred to as “duct width”) changes with respect to the flow direction Y. At least a part of the duct width changing portion 20 is disposed outside in the width direction X of the heat transfer tube group 4 at the position in the flow direction Y where the heat transfer tube group 4 is disposed.
In the present embodiment, the duct width changing portion 20 is provided with an enlarged portion 20A that gradually increases as the duct width becomes downstream, and is continuously provided downstream of the enlarged portion 20A and gradually decreases as the duct width becomes downstream. The reduced portions 20 </ b> B are provided on both sides in the width direction X outside the heat transfer tube group 4. That is, in the present embodiment, the duct width changing unit 20 increases or decreases (changes) in the duct width on both sides in the width direction X of the heat transfer tube group 4.

  Each enlarged portion 20A is defined by a duct side wall portion 21 that is inclined outward toward the downstream side. The duct side wall portion 21 is provided from the axial center line CL of the first stage heat transfer tube 40 to the axial center line CL of the fifth stage heat transfer tube 40 which is the last stage. The heat transfer tube group 4 is provided over substantially the entire length.

  Each reduction part 20B is each prescribed | regulated by the duct side wall part 22 inclined inward toward the downstream from the axial center line CL of the heat exchanger tube 40 of the 5th stage | stage which is the last stage.

  The width dimensions of the exhaust gas supply duct 100 and the exhaust gas discharge duct 101 are the same or substantially the same, and the flow path width of the exhaust gas G expanded by the enlarged portion 20A is reduced by the reduced portion 20B (from the enlarged portion 20A). (The upstream side) is also returned to the channel width.

[1-2. Action / Effect]
According to 1st Embodiment of this invention, since the duct 2 which accommodates the heat exchanger tube group 4 is provided with the duct width change part 20, generation | occurrence | production of the standing wave of the duct width direction X is substantially carried out. Can be suppressed.
That is, when the duct width is constant and the frequency of the standing wave is constant, the standing wave is strengthened toward the downstream side, whereas in the duct width changing portion 20 with respect to the flow direction Y, Since the duct width changes, the frequency of the standing wave also changes with respect to the flow direction, and the intensity of the frequency component of the standing wave can be dispersed and reduced, thereby substantially reducing the occurrence of the standing wave in the duct width direction. Can be suppressed.

Thereby, it is possible to prevent the occurrence of self-excited sound (cattle noise) with a simple configuration in which the duct width changing portion 20 is provided in the duct 2 without using the vibration isolating baffle. In addition, unlike the techniques disclosed in Patent Document 1 and Patent Document 2, since the equipment for the sound absorbing material and the resonance cavity is not provided in the duct internal space 3, there is no concern about the deterioration of these equipment, and it is easily put into practical use. Can be
Therefore, the occurrence of canning can be prevented while suppressing an increase in the manufacturing cost of the heat exchange device.

  Moreover, since the flow path width of the exhaust gas G expanded by the expansion part 20A is returned to the original flow path width by the reduction part 20B, it is possible to suppress an increase in the size of the equipment and an accompanying increase in manufacturing cost.

[1-3. Modified example]
The configuration of the modification will be described with reference to FIG.
FIG. 2 is a schematic cross-sectional view showing the configuration of the heat exchange device 1A according to this modification. In addition, the same code | symbol is attached | subjected about the component same as the said 1st Embodiment, and the description is abbreviate | omitted.
In the above embodiment, the duct width changing portion 20 is formed from the axial center line CL of the first stage heat transfer tube 40, but the duct width changing portion 20 is downstream of the upstream end 40 u of the third stage heat transfer tube 40 ( The position of the upstream end 40u of the third stage heat transfer tube 40 is set to the start end (upstream end) as in the heat exchange device 1A of the present modification shown in FIG. ), The duct width changing portion 20 may be arranged.

The reason for this will be described with reference to FIG.
FIG. 3 is a graph in which the measurement result of the sound pressure level in a case where the duct width is constant is plotted on a graph in which the horizontal axis is frequency [Hz] and the vertical axis is sound pressure level [dB]. The sound pressure level in the first heat transfer tube 40, the broken line indicates the sound pressure level in the third heat transfer tube 40, and the solid line indicates the sound pressure level in the fourth heat transfer tube 40. As is apparent from FIG. 3, an abnormal noise (that is, a kettle noise) with a high sound pressure level is generated in the heat transfer tube 40 in the fourth stage. Therefore, since no noise is generated on the upstream side of at least the third-stage heat transfer tube 40, the duct width changing portion 20 is set so that the duct width changes from the upstream end 40u of the third-stage heat transfer tube 40. If it arrange | positions, it is thought that the suppression effect of the hook noise of the duct width change part 20 becomes effective.
Since other configurations are the same as those of the first embodiment, the description thereof is omitted.

[2. Second Embodiment]
[2-1. Constitution]
A heat exchange device 1B of the present embodiment will be described with reference to FIG.
FIG. 4 is a schematic cross-sectional view showing the configuration of the heat exchange device 1B of the present embodiment. In addition, the same code | symbol is attached | subjected about the component same as the said 1st Embodiment, and the description is abbreviate | omitted.
In the heat exchanging device 1B of the present embodiment, through holes 5a having small diameters are arranged evenly on both outer sides of the heat transfer tube group 4, that is, between the enlarged portion 20A and the reduced portion 20B and the heat transfer tube group 4. A perforated plate 5 is provided. The perforated plate 5 extends from the upstream end of each enlarged portion 20A, in other words, from the root (upstream end) 21a of each duct side wall portion 21 to the downstream side and extends to the root (downstream end) 22a of each duct side wall portion 22. Is provided.
Other configurations are the same as those of the first embodiment, including the configuration of applicable modifications, and thus the description thereof is omitted.

[2-2. Action / Effect]
According to the heat exchange device 1B of the second embodiment of the present invention, by providing the perforated plate 5, it is possible to suppress the exhaust gas G from flowing out of the heat transfer tube group 4 as shown by an arrow G1 in FIG. (The flow of exhaust gas G that does not contribute to heat exchange can be suppressed). In addition, since the perforated plate 5 is a porous body, the standing wave passes through the perforated plate 5, so that the perforated plate 5 itself does not generate a standing wave, and the function of the duct width changing portion 20 is impaired. There is no.
Therefore, in addition to obtaining the same effect as the heat exchange device 1 of the first embodiment, there is an advantage that the heat exchange performance can be improved as compared with the heat exchange device 1 of the first embodiment.

  If the aperture ratio of the porous plate 5 is too high, the effect of regulating the flow of the exhaust gas G by the porous plate 5 is impaired. If the aperture ratio of the porous plate 5 is too low, the porous plate 5 itself generates a standing wave. Thus, the significance of providing the duct width changing portion 20 is impaired. A suitable aperture ratio of the perforated plate 5 is, for example, 30%, but use of an aperture ratio other than 30% is not excluded.

[3. Modified example]
(1) The configuration of the modification will be described with reference to FIG.
FIG. 5 is a schematic cross-sectional view showing the configuration of the heat exchanging device 1C according to this modification. In addition, the same code | symbol is attached | subjected about the component same as said each embodiment, and the description is abbreviate | omitted.
In each said embodiment, although the duct width change part 20 was comprised so that a duct width might change on the both outer sides of the heat exchanger tube group 4, like the heat exchange apparatus 1C shown in FIG. 5, one side (here left side) It is good also considering the duct side wall part 23 of this as a flat shape along a flow direction. That is, the duct width changing portion 20 ′ may be configured such that the duct width changes only on one outer side (here, the right side) of the heat transfer tube group 4 in the duct width direction X.

Further, in each of the above embodiments, the duct width changing portion 20 in which the enlarged portion 20A is formed on the upstream side and the reduced portion 20B is formed on the downstream side is adopted as the duct width changing portion. As described above, the duct width changing portion may be configured by providing the reduced portion 20B on the upstream side and the enlarged portion 20A on the downstream side. Also in this case, the duct width changing portion may be configured such that the duct width changes only on one side (one outer side) of the heat transfer tube group 4, or the duct width changes on both outer sides of the heat transfer tube group 4. You may comprise as follows.
Since other configurations are the same as those of the first embodiment, the description thereof is omitted.

  (2) In the above embodiment, the heat exchange device is configured by arranging the heat transfer tubes 40 in a staggered arrangement of 19 rows × 5 stages, but the configuration of the heat exchange device is not limited to this. For example, the number of rows and the number of stages of the heat transfer tubes 40 are not limited to the above numbers, and can be set as appropriate, and the heat exchange apparatus may be configured by arranging the heat transfer tubes 40 in a lattice arrangement.

  (3) In the said embodiment, although this invention was applied to the heat exchange apparatus of HRSG, it is applicable to the heat exchange apparatus used for various uses, such as a general steam boiler provided with a burner, and a water heater.

1, 1A, 1B, 1C Heat exchange device 2 Gas duct 20, 20 'Duct width changing portion 20A Enlarged portion 20B Reduced portion 21, 22, 23 Duct side wall portion 3 Internal space of gas duct 2 4 Heat transfer tube group 40 Heat transfer tube 5 Porous plate 5a Through hole G Exhaust gas (heat source gas)
X Duct longitudinal direction Y Duct width direction

Claims (9)

A gas duct through which a heat source gas flows in an internal space; and a heat transfer tube group that is arranged in the internal space and includes a plurality of heat transfer tubes arranged in the flow direction of the heat source gas and in the width direction orthogonal to the flow direction. In the heat exchange device
The gas duct includes a width dimension changing portion in which the dimension in the width direction is changed with respect to the flow direction,
At least a part of the width dimension changing portion is arranged on the outer side in the width direction of the heat transfer tube group. 2. The heat exchange device according to claim 1, wherein the width dimension changing portion is located after the upstream end of the heat transfer tube arranged in the third stage from the upstream side in the flow direction. 3. The heat exchange device according to claim 1, wherein the width dimension changing portion includes an enlarged portion whose dimension in the width direction is increased toward the downstream side in the flow direction. 4. The width dimension changing portion includes a reduction portion on the downstream side in the flow direction of the enlargement portion, the reduction portion having a size in the width direction that decreases toward the downstream side in the flow direction. Heat exchange equipment. 5. The heat exchange device according to claim 3, wherein a perforated plate extending along the flow direction is provided outside the heat transfer tube group in the width direction. 6. 3. The heat exchange device according to claim 1, wherein the width dimension changing unit includes a reduction unit that reduces a dimension in the width direction toward the downstream side in the flow direction. The width dimension changing part includes an enlarged part on the downstream side in the flow direction of the reduction part, and an enlarged part whose dimension in the width direction is increased toward the downstream side in the flow direction. Heat exchange equipment. The heat exchange apparatus according to any one of claims 1 to 7, wherein the width dimension changing portion changes the dimension in the width direction on both sides in the width direction of the heat transfer tube group. The heat exchange apparatus according to any one of claims 1 to 7, wherein the width dimension changing portion changes in the width direction only on one side in the width direction of the heat transfer tube group. .

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