JP2013178018A - Heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve efficiency of heat exchange without causing an increase in the scale of a heat exchanger which is mounted on a vehicle and constituted while including many heat transfer tubes 2.SOLUTION: A heat exchanger includes a body unit 3 constituted by arranging a plurality of heat transfer tubes side by side with a space from one another. The heat transfer tubes each has a flat cross section including a major axis and a minor axis orthogonal thereto at an inflow part 31 in which cooling air flows and an outflow part 32 out of which the cooling air flows at the body unit, and are arranged having major axis direction along the flow direction of the cooling air.

Description

  The technology disclosed herein relates to a heat exchanger that is mounted on a vehicle such as a railway vehicle and configured to radiate a target liquid that flows through a number of heat transfer tubes.

  Patent Document 1 describes a heat exchanger (oil cooler) that is mounted on a railway vehicle and cools insulating oil of a transformer. The oil cooler includes an oil distribution section, an oil collecting section, and a plurality of cooling pipes bent in a U-shape so as to connect the oil distribution section, and each cooling pipe travels with the traveling wind of the railway vehicle. The oil flowing in the cooling pipe is configured to radiate heat by being exposed to. The cooling pipe used for such a heat exchanger is generally constituted by a circular pipe having a circular cross section.

  Moreover, in patent document 2, as a heat exchanger provided in an air-conditioning refrigerating apparatus, a refrigerant pipe arranged through a large number of laminated plate-like fins is configured by an elliptical tube having an elliptical cross section. Is described. In this heat exchanger, the refrigerant pipes, which are elliptical pipes, are arranged in a line in a direction in which the major axis direction coincides with the flow direction and perpendicular to the flow direction. It is small.

Japanese Utility Model Publication No. 54-12817 JP 2001-165586 A

  By the way, in a heat exchanger mounted on a vehicle such as a railway vehicle as described in Patent Document 1, it is possible to achieve high performance without causing an increase in size due to the limited installation space. Desired. For example, when the number of heat transfer tubes is increased in order to improve the heat exchange efficiency, a large number of heat transfer tubes must be arranged at a relatively high arrangement density, and the interval between adjacent heat transfer tubes becomes narrow. This is because the air flow rate at the end of the heat exchanger on which the cooling air flows in, that is, the projected area of the entire end surface on the inflow side of the heat exchanger constituted by a plurality of heat transfer tubes (in the direction of the cooling air flow). The ratio of the projected area of all the gaps between the heat transfer tubes to the projected area) is reduced to inhibit the inflow of cooling air, and the ventilation rate at the end on the side where the cooling air flows out in the heat exchanger is also reduced. As a result, the outflow of cooling air is also inhibited. As a result, the flow rate of the traveling wind passing through the heat exchanger decreases, and the initial purpose of improving the heat exchange efficiency cannot be achieved. On the contrary, if the interval between the heat transfer tubes is increased in order to ensure a ventilation rate higher than a predetermined value, the outer size of the entire heat exchanger becomes large.

  The technology disclosed herein has been made in view of such a point, and the object is to increase the size of a heat exchanger that is mounted on a vehicle and includes a large number of heat transfer tubes. Without improving the heat exchange efficiency.

  The heat exchanger disclosed herein is a heat exchanger that is mounted on a vehicle and configured to dissipate a target fluid that flows in a plurality of heat transfer tubes by passing cooling air flowing in a predetermined direction. .

  The heat exchanger includes a distribution unit configured to distribute the target fluid to the plurality of heat transfer pipes while introducing the target fluid, and an interval in the flow direction of the cooling air with respect to the distribution unit. A collecting portion that is disposed in a space and configured to collect and discharge the target fluid flowing from the plurality of heat transfer tubes; and the distribution portion and the collecting portion that are configured to communicate with each other. And a main body portion that is configured by arranging a plurality of heat transfer tubes side by side at intervals, and through which the cooling air passes between the heat transfer tubes.

  And the said main-body part is comprised by the part of the said heat exchanger tube extended so that it may cross | intersect the flow direction of the said cooling air from the said distribution part or the said gathering part, and the part of the said heat exchanger tube is in the flow direction of the said cooling air An inflow portion for allowing the traveling wind to flow into the main body through a plurality of inflow ends arranged in a direction orthogonal to each other, and extending so as to intersect the flow direction of the cooling air from the collecting portion or the distributing portion. An outflow portion configured to include a portion of the heat transfer tube, and the portion of the heat transfer tube that causes the running air to flow out from the main body portion via an outflow end that is arranged in a plurality in a direction orthogonal to the flow direction of the cooling air; And a passage of the cooling air flowing from the inflow portion toward the outflow portion along the heat transfer tube. The heat transfer tube has a flat cross-sectional shape including a major axis and a minor axis orthogonal to the inflow part and the outflow part, and the direction of the major axis is It arrange | positions in the direction in alignment with the flow direction of the said cooling wind.

  Here, the “vehicle” may be a railway vehicle including a Shinkansen, a conventional line (including a private railway line), a subway line, etc., a vehicle that travels on a track such as a monorail, a tram, etc. Also, a trackless vehicle such as a truck may be used.

  The “cooling wind” may be a forced wind that is forcibly generated by, for example, a blower or the like, or a relative air flow generated when the vehicle is traveling linearly in one direction, that is, a traveling wind. Also good. In the case of traveling wind, the flow direction of the traveling wind is a mainstream direction of the traveling wind and is a linear direction opposite to the traveling direction of the vehicle.

  “Extending so as to intersect the flow direction of the cooling air” includes extending in a direction other than the direction coinciding with the flow direction of the cooling air, and naturally extending in a direction orthogonal to the flow direction of the cooling air. . "Extends along the flow of cooling air" means that in addition to extending in a direction that coincides with the flow direction of the cooling air, in comparison with the above-mentioned "extending so as to intersect the flow direction of the cooling air" It also includes extending in a direction almost coincident with the flow direction of the cooling air. Therefore, it does not include extending in a direction orthogonal to the flow direction of the cooling air.

  When the cooling air is traveling air, the “inflow portion” and the “outflow portion” of the main body are set according to the moving direction of the vehicle. That is, if the vehicle is a vehicle whose traveling direction is reversed, such as a railway vehicle, the “inflow portion” and the “outflow portion” are interchanged according to the traveling direction of the railway vehicle.

  According to the above configuration, the main body portion is configured to have an inflow portion into which cooling air flows, an outflow portion from which cooling air flows out, and a ventilation portion through which the cooling air flowing in from the inflow portion flows toward the outflow portion. At the inflow end of the inflow portion, the cooling air flows between the heat transfer tubes and flows into the main body. The inflowing cooling air passes through the ventilation portion, and then, at the outflow end of the outflow portion. It flows out from the main body through the heat tubes. Thus, heat exchange is performed between the target fluid flowing in the heat transfer tube and the cooling air, and the target fluid dissipates heat.

  In the above-described configuration, the cross-sectional shape of each heat transfer tube in the inflow portion and the outflow portion of the main body is a flat shape including a major axis and a minor axis perpendicular to the major axis. The direction of is arranged in a direction along the flow direction of the cooling air. As a result, the short diameter of each heat transfer tube is projected in the flow direction of the cooling air at the inflow end in the inflow portion. Therefore, compared with the case where the inflow portion is configured by a heat transfer tube having a circular cross section. (However, in the heat transfer tube having a circular cross section, the flow rate of the target fluid flowing inside the heat transfer tube having the flat cross section is set to be the same, and the number of the arranged fluids is also set to be the same.) The outer dimensions of the inflow parts are equal to each other). Or when setting the air flow rate to be the same, it is possible to arrange more heat transfer tubes with a flat cross section than when arranging heat transfer tubes with a circular cross section (however, heat transfer tubes with a circular cross section For the heat transfer tube having a flat cross section, the flow rate of the target fluid flowing inside the heat transfer tube is set to be the same, and the outer dimensions of the inflow portion of the main body are equal to each other). This makes it possible to increase the heat transfer area without increasing the inflow amount of the cooling air in the inflow portion or decreasing the inflow amount of the cooling air.

  Further, in the above configuration, since the same configuration as that of the inflow portion is adopted in the outflow portion, the ventilation portion is compared with the case where the main body portion is configured by the heat transfer tube having a circular cross section at the outflow end in the outflow portion. When the rate is increased or the ventilation rate is set to be the same, more heat transfer tubes having a flat cross section can be arranged. This makes it possible to increase the heat transfer area without increasing the outflow amount of the cooling air in the outflow portion or decreasing the outflow amount of the cooling air. And, in this way, smoothly flowing out the cooling air in the outflow part also reduces the pressure loss of the cooling air passing through the main body, and therefore further promotes the inflow of the cooling air in the inflow part. It will also do.

  Thus, in the above configuration, by arranging the heat transfer tubes having a flat cross section in a predetermined direction in both the inflow portion and the outflow portion, the heat exchange efficiency is effectively increased without causing an increase in the size of the heat exchanger. It becomes possible.

  In addition, in this way, the cooling air can easily flow into the inflow portion, particularly in the case of a traveling wind self-cooling type heat exchanger, even when the dynamic pressure on the upstream side of the inflow portion is low, it flows into the main body. This is advantageous in ensuring a sufficient flow rate of the traveling wind. In other words, even when an obstacle or the like is disposed upstream of the main body in the direction of the flow of the traveling wind, the inflow flow rate of the traveling wind is sufficiently secured and the heat exchange efficiency is maintained above a predetermined level. It becomes possible to do.

  The heat transfer tube is bent in a U shape so as to continuously constitute the inflow portion, the outflow portion, and the ventilation portion, and the U-shaped heat transfer tube includes the major axis and the minor axis. Having a flat cross-sectional shape, thereby having an enlarged heat transfer surface extending in the direction of the major axis, and the U-shaped heat transfer tube is also orthogonal to the flow direction of the cooling air, The multiple heat transfer surfaces of the heat transfer tubes constitute a heat transfer tube group arranged along the flow direction of the cooling air by being arranged in parallel from the inside to the outside of the vehicle, and the main body The part is configured by stacking a plurality of the heat transfer tube groups with a predetermined gap therebetween, and thereby sandwiched between the heat transfer tube groups adjacent to each other by the expanded heat transfer surface of each heat transfer tube. The cooling air flow path extends straight in the flow direction of the cooling air. Are formed may be.

  In this configuration, the main body has a plurality of U-shaped heat transfer tubes arranged in parallel from the inside of the vehicle to the outside, with a plurality of heat transfer tube groups with a predetermined interval, A flow path that is configured by being stacked and extends straight in the flow direction of the cooling air is formed between adjacent heat transfer tube groups. Thus, since the flow path of the cooling air is formed to extend straight in the flow direction, the pressure loss of the cooling air passing through the main body is further reduced. As described above, this suppresses the reduction of the ventilation rate in each of the inflow portion and the outflow portion, and in combination with the configuration for ensuring the inflow flow rate and the outflow flow rate of the cooling air, It is advantageous for improving the heat exchange efficiency by suppressing a decrease in the flow velocity of the passing cooling air.

  In addition, the flow path of the cooling air formed in the main body is sandwiched by the enlarged heat transfer surface that is larger than the heat transfer tube having a circular cross section by adopting a flat cross section, so that the overall size of the main body is not increased. The heat transfer area that can be contacted by the cooling air is effectively expanded. This is also advantageous for improving the heat exchange efficiency of the heat exchanger.

  The heat transfer tube may be configured such that a ratio (a / b) of the length a of the major axis to the length b of the minor axis is 2 <a / b <10.

  By bringing a / b closer to 1, the cross section of the heat transfer tube approaches a circular shape, and the effects of securing the ventilation rate in the inflow portion and the outflow portion and expanding the heat transfer area in the heat transfer tube group described above. descend. Therefore, it is preferable that 2 <a / b.

  On the other hand, by increasing a / b, the natural frequency of the heat transfer tube gradually decreases. For example, the flow velocity of the cooling air is 120 km / h (this is included in the travel speed range of the railway vehicle, In this case, the frequency of the Karman vortex is 250 Hz. Therefore, by setting a / b <10, the natural frequency of the heat transfer tube is shifted with respect to the frequency of the Karman vortex. It becomes possible. That is, by setting a / b <10, resonance of the heat transfer tube due to Karman vortices can be avoided.

  In the inflow portion, at least the heat transfer tube disposed on the cooling air inflow side is provided with a turbulence promoting member that promotes turbulence of the cooling air flowing into the main body on the peripheral surface thereof. It is good as well.

  By doing so, the cooling air that has flowed into the main body is quickly turbulent, and the heat exchange efficiency is further improved.

  As described above, according to the above heat exchanger, the heat transfer tubes having a flat cross section are arranged in both the inflow portion and the outflow portion of the main body so that the major axis direction is in the direction along the flow direction of the cooling air. Therefore, at each of the inflow end and the outflow end, at least the ventilation rate can be maintained at a predetermined level or more, and the amount of cooling air flowing into and out of the main body can be sufficiently secured. It is possible to efficiently increase the heat exchange efficiency without incurring an increase in size.

It is a front view which shows the heat exchanger mounted in the rail vehicle. It is a top view of a heat exchanger. It is a side view of a heat exchanger. (A) It is a figure which expands and shows a part of aa cross section of FIG. 2, and (b) a part of bb cross section of FIG. (A) As a result of CFD showing a flow field around a heat exchanger constituted by a circular pipe, (b) As a result of CFD showing a flow field around a heat exchanger constituted by a flat pipe. It is a figure which shows the relationship between the aspect-ratio a / b of a heat exchanger tube cross section, and the resonant frequency of a heat exchanger tube. It is a figure which shows the relationship between the aspect-ratio a / b of a heat exchanger tube cross section, and the pressure loss of a main-body part. It is the result of CFD which shows the mode of a flow when an obstruction is attached before and behind a heat exchanger. (A) It is a perspective view which shows the heat exchanger tube which attached the turbulent flow promotion member to the surrounding surface, (b) It is sectional drawing which expands and shows the inflow part comprised by the heat exchanger tube which attached the turbulent flow promotion member.

  Hereinafter, an embodiment of a heat exchanger will be described based on the drawings. In addition, the following description of preferable embodiment is an illustration. 1 to 3 show a heat exchanger 1 mounted on a railway vehicle 91 as a vehicle that travels along a rail 92 that is a track. FIG. 1 is arranged in an underfloor portion of the railway vehicle 91. FIG. 2 is a front view of the heat exchanger 1 when the heat exchanger 1 is viewed from the lateral position of the railway vehicle 91 in the vehicle width direction, and FIG. 2 shows the heat corresponding to when the heat exchanger 1 is viewed from above. FIG. 3 is a plan view of the heat exchanger 1, and FIG. 3 is a side view of the heat exchanger 1 corresponding to the heat exchanger 1 when viewed in the traveling direction of the railway vehicle 91. In FIG. 1 to FIG. 3, illustrations of a support for supporting the heat transfer tube 2 and a cover surrounding the entire heat exchanger 1 are omitted for easy understanding. In the following description, for the sake of convenience, the traveling direction of the railway vehicle 91 (left and right direction in the drawing of FIG. 1) is the X direction, the vehicle width direction of the railway vehicle 91 (left and right direction in the drawing of FIG. 2) is the Y direction, A vertical direction orthogonal to the X and Y directions (up and down direction in FIG. 1 and FIG. 2) may be referred to as a Z direction.

  This heat exchanger 1 is a kind of a multi-tube heat exchanger having a large number of heat transfer tubes 2 through which a target fluid that is a target of heat exchange flows. In this example, a transformer (illustrated) mounted on a railway vehicle 91 is illustrated. The insulating oil of (omitted) is the target fluid, and the insulating oil functions as a cooler for radiating and cooling the insulating oil in the heat transfer pipe 2. As shown briefly in FIG. 3, the heat exchanger 1 is disposed at an outer position in the vehicle width direction under the floor of the railroad vehicle 91. Be exposed. In the illustrated example, as the railway vehicle 91 travels from left to right on the paper (see solid arrows), the heat exchanger 1 is exposed to traveling wind flowing from right to left on the paper (see white arrows). Indicates the state. In addition, if the traveling direction of the railway vehicle 91 is opposite to the illustrated example, the flow direction of the traveling wind is naturally opposite to the illustrated example. Thus, the heat exchanger 1 in this example is not a forced air cooling type using, for example, a blower but a self-cooling type using traveling wind. The traveling wind self-cooling heat exchanger 1 contributes to energy saving of the entire railway vehicle 91 through simplification of the cooling system, weight reduction, and energy reduction. Note that a blower for driving the vehicle at least while the vehicle is stopped and supplying cooling air to the heat exchanger 1 may be provided in order to actively dissipate the insulating oil even when the vehicle is stopped. Further, the heat exchanger 1 to which the technology disclosed herein is applicable is not limited to the traveling wind self-cooling type, and may be a forced air cooling type using a blower or the like.

  In the illustrated example, another vehicle member 93, 93 is disposed under the floor of the railway vehicle 91 at the front and rear positions in the X direction across the heat exchanger 1. These vehicle members 93 are formed with inclined surfaces for guiding the flow of traveling wind into the heat exchanger 1. In addition, such a vehicle member may not be disposed at the front and rear positions of the heat exchanger 1.

  The heat exchanger 1 includes a distribution unit 11 configured to introduce insulating oil from the transformer, a collection unit 12 configured to discharge the insulation oil to the transformer, a distribution unit 11 and a collection unit. A plurality of heat transfer tubes 2 communicating with each other 12 are provided with a main body portion 3 configured by being arranged in a lattice shape.

  The distribution unit 11 is connected to a transformer (not shown) and has a function of distributing the insulating oil flowing from the transformer to the heat transfer tubes 2. In this example, the distribution unit 11 is formed in a rectangular box shape that is a vertically long rectangle when viewed from the front, and the connection surface 111 to which the inlet opening end of each heat transfer tube 2 is connected extends outward in the vehicle width direction. It is fixed to the vehicle body of the railway vehicle 91 so as to face.

  The collecting unit 12 is connected to the transformer and has a function of collecting the insulating oil that has passed through the heat transfer tubes 2 and discharging it to the transformer (returning the insulating oil). In this example, the collecting portion 12 is formed in the same shape as the distributing portion 11. The gathering portion 12 is arranged side by side with a predetermined interval in the X direction with respect to the distributing portion 11, and the connection surface 121 to which the outlet opening end of each heat transfer tube 2 is connected extends outward in the vehicle width direction. It is fixed to the vehicle body of the railway vehicle 91 so as to face.

  As shown in FIG. 2, each heat transfer tube 2 is bent at two locations so as to be U-shaped (or U-shaped) in plan view, whereby each heat transfer tube 2 is distributed. A portion (first portion) extending outward in the Y direction from the inlet opening end connected to the portion 11 and a portion (first portion) extending outward in the Y direction from the outlet opening end connected to the collecting portion 12 2 portion) and a portion (third portion) extending along the X direction so as to allow the end portions of the first portion and the second portion to communicate with each other. Here, the shape of each of the two heat transfer tubes 2 bent by approximately 90 ° is referred to as a U-shape, but the bending angle may be set within an appropriate range, and the first portion and the second portion And if it is the shape containing a 3rd part, all are U-shaped.

  FIG. 4A shows a part of the transverse cross section (XZ cross section) of the heat transfer tube 2 in the vicinity of the distribution unit 11, and the heat transfer tube 2 has a predetermined pitch P1 in the X direction and Are arranged in a square lattice so as to have a predetermined pitch P2 in the Z direction, and are connected to the connection surface 111 of the distributor 11. In the illustrated example, the pitch P1 and the pitch P2 are set equal. Although illustration is omitted, as in FIG. 4A, the heat transfer tube 2 has a predetermined pitch P1 in the X direction and a predetermined pitch P2 in the Z direction with respect to the collective portion 12 as well. In this way, they are arranged in a square lattice shape and connected to the connection surface 121. The pitches P1 and P2 may be different.

  Each of the heat transfer tubes 2 is also disposed without changing the mutual position between the inlet opening end connected to the distribution portion 11 and the outlet opening end connected to the collecting portion 12. For this reason, also in the cross section (YZ cross section) corresponding to the center position in the length direction of each heat transfer tube 2 shown in FIG. 4B, the heat transfer tube 2 is predetermined in each of the Y direction and the Z direction. Are arranged in a square lattice pattern so as to have the pitches P1 and P2.

  Thus, in the heat exchanger 1 shown in the figure, the heat transfer tubes 2 bent in a U-shape, 10 in the X direction and 21 in the Y direction, are connected to the distributing unit 11 and the collecting unit 12. Thus, although the main body 3 having a substantially rectangular shape is configured in plan view, a part of the heat transfer tube that should be disposed outward and downward in the vehicle width direction avoids interference with an obstacle or the like. Further, the arrangement is omitted (see FIGS. 1 and 3). The main body 3 is constituted by a second portion (or first portion) of the heat transfer tube 2 extending in the Y direction orthogonal to the flow direction (X direction) of the traveling wind, and the traveling wind flows into the main body 3. Traveled from the main body 3 and composed of an inflow portion 31 that is a portion to be moved and a first portion (or second portion) of the heat transfer tube 2 extending in the Y direction orthogonal to the flow direction (X direction) of the traveling wind. The outflow portion 32, which is a portion from which the wind flows out, and the third portion of the heat transfer tube 2 extending along the flow direction (X direction) of the traveling wind, the traveling wind that has flowed in from the inflow portion 31 into the outflow portion 32. It has the ventilation part 33 which flows along the heat exchanger tube 2 toward. As described above, when the traveling direction of the railway vehicle is reversed in the reverse direction, the inflow portion 31 and the outflow portion 32 of the main body 3 are set in the opposite manner to the illustrated example.

  In other words, the heat transfer tube 2 is bent into a U shape so as to continuously form the inflow portion 31, the outflow portion 32, and the ventilation portion 33, and the U-shaped heat transfer tube 2 is The heat transfer tube group as shown in FIG. 2 is configured by being arranged in parallel from the inside of the railway vehicle to the outside, orthogonal to the flow direction (X direction). As shown in FIG. 1 or 3, the plurality of layers are arranged with a predetermined gap in the Z direction. Thus, in the main body portion 3, the flow path of the traveling wind is formed between the heat transfer tube groups adjacent to each other in the Z direction so as to extend straight in the flow direction (X direction) of the traveling wind. It will be.

In the conventional heat exchanger, each heat transfer tube 2 is constituted by a circular tube as virtually shown in FIG. 4A. In this heat exchanger 1, FIGS. 4A and 4B are used. As shown in the figure, a flat tube having a longer horizontal width (corresponding to the major axis) than the height in the vertical direction (corresponding to the minor axis), specifically, arcs at both ends of the two sides parallel to the vertical direction It is comprised by the pipe of the cross-sectional shape connected by. Thus, the cooling efficiency is improved without increasing the size of the main body 3. That is, each heat transfer tube 2 is constituted by a flat tube set so that the internal cross-sectional area is substantially equal to that of the conventional circular heat transfer tube shown virtually in FIG. Thereby, the heat-transfer area which expands in a horizontal direction is expanded rather than a circular heat exchanger tube, ensuring the flow volume of insulating oil comparable as the conventional circular heat exchanger tube. Further, in this example, the heat transfer tubes 2 are arranged in a square lattice shape at the same pitches P1 and P2 as the heat exchanger using the conventional circular heat transfer tubes, and thereby the outer dimensions of the entire main body 3 are as follows. In the inflow portion 31 and the outflow portion 32, the gap L _z between the heat transfer tubes 2 in the Z direction is wider than the conventional gap L _z ′, while the heat transfer tubes in the X direction are substantially the same. The gap L _x between the two is made narrower than the conventional gap L _x ′.

This is because, as shown in FIG. 4 (a), in the inflow portion 31 of the main body 3, the end surface (right end in the figure) into which the traveling wind flows is an opening through which the traveling wind can flow. area (corresponding to the distance L _z) means that large. That is, the ventilation rate at the inflow end surface of the inflow portion 31 (the ratio of the projected area of the entire gap between the heat transfer tubes 2 to the projected area of the entire main body 3, see also FIG. 3) becomes higher than before, and the traveling wind It becomes easy to flow into the main body 3.

  In addition, since the heat transfer tubes 2 are arranged in a square lattice shape, a wide flow path corresponding to a wide opening is formed in the inflow portion 31 so as to extend straight in the X direction. In the part 31, the pressure loss with respect to the flow direction of the traveling wind is reduced.

On the other hand, in the inflow portion 31, the gap L _x between the heat transfer tubes 2 in the X direction becomes narrow, so that the traveling wind that has flowed into the inflow portion 31 is prevented from flowing in the Z direction orthogonal to the flow direction. Is done.

  Thus, in the inflow portion 31 of the main body 3, the ventilation rate is higher than before, the pressure loss in the flow direction of the traveling wind (X direction) is reduced, and Z orthogonal to the flowing direction of the traveling wind. In combination with the suppression of the flow in the direction, the flow rate of the traveling wind in the main body 3 is sufficiently secured, and the decrease in the flow velocity of the traveling wind in the inflow portion 31 is suppressed.

Moreover, in the ventilation part 33 continuing to the inflow part 31, as shown in FIG. 4 (b), the heat transfer tubes 2 are arranged in a square lattice pattern with pitches P 1 and P 2, and therefore the heat transfer tubes in the Z direction. The gap between the two is equal to the gap L _z at the inflow portion 31, and the gap L _y between the heat transfer tubes 2 in the Y direction is equal to the gap L _x at the inflow portion 31.

  As a result, in the inflow portion 31 described above, a flow path that is wide in the vertical direction and is formed to extend straight in the flow direction of the traveling wind (X direction) is also a wide passage in the vertical direction in the ventilation portion 33. As is, it is formed to extend straight in the X direction. Therefore, also in the ventilation part 33, the pressure loss about the flow direction (direction orthogonal to the paper surface in FIG.4 (b)) of driving | running | working wind becomes low.

Moreover, in the ventilation part 33, since the space | interval of the adjacent heat exchanger tubes 2 becomes narrow about the Y direction (refer clearance gap _Ly ), the traveling wind which flows through the inside of a ventilation part is Z direction orthogonal to the flow direction. It is suppressed that it flows into. Thus, a decrease in the flow velocity of the traveling wind is suppressed even in the ventilation portion.

  Further, in the ventilation portion 33, at the outer end in the vehicle width direction (the left end in FIG. 4B), an opening is formed outward in the vehicle width direction between the heat transfer tubes 2 adjacent in the vertical direction. Since it has a relatively wide opening, as shown by a virtual white arrow in the figure, the traveling wind flows from the outside of the railway vehicle to the inside of the ventilation part through this opening. To be promoted.

  Further, in the outflow portion 32, similarly to the inflow portion 31 described above, the air flow rate at the outflow end surface (the end surface from which the traveling wind flows out and the left end in FIGS. The pressure loss in the flow direction (X direction) is reduced, and further, the flow in the Z direction orthogonal to the flow direction of the traveling wind is suppressed.

  As a result, the flow rate flowing out from the main body 3 can be made sufficiently high so that the traveling wind can flow out from the main body 3 smoothly. This also reduces the pressure loss of traveling wind in the main body 3, which is advantageous for the inflow of traveling wind through the inflow portion 31. That is, the decrease in the flow velocity of the traveling wind in the main body 3 is further suppressed.

  Thus, as a result of suppressing the decrease in the flow velocity of the traveling wind in the main body 3 while sufficiently securing the inflow amount of the traveling wind to the main body 3, the heat exchange efficiency of the heat exchanger 1 is increased.

  And as above-mentioned, in the flat heat exchanger tube 2, the heat-transfer area which spreads in a horizontal direction is expanded rather than a circular heat exchanger tube, and the heat-transfer surface expanded by arranging the flat tube 2 in parallel with multiple. However, it becomes substantially continuous in the X and Y directions, and a wide flat heat transfer surface is formed so as to sandwich the flow path of the traveling wind formed between the heat transfer tube groups. By flattening the heat transfer tube 2 in this way, it is possible to effectively expand the heat transfer area facing the flow path of the traveling wind without increasing the size of the main body 3. This is also advantageous for improving the heat exchange efficiency.

  In this example, the air flow rate is made higher than that of the conventional heat exchanger made of circular heat transfer tubes by making the arrangement pitch and the number of the heat exchangers the same. If the flat heat transfer tube 2 is used, the pitch of the arrangement becomes shorter than the conventional arrangement. As a result, even if the overall outer dimensions of the heat exchanger 1 are the same, the heat transfer tube 2 It is possible to increase the number of arrangements than in the past. Since this configuration is substantially the same as the conventional ventilation rate, it is possible to increase the flow rate of the insulating oil and expand the heat transfer area without increasing the pressure loss of the traveling wind. This also increases the heat exchange efficiency of the heat exchanger 1.

  As described above, in FIGS. 1 to 3, illustration of the support that supports the heat transfer tube 2 is omitted, but this support extends in, for example, the XZ plane at the inflow portion 31 and the outflow portion 32. A plurality of heat transfer tubes 2 that are configured by flat plates and arranged in a square lattice pattern in the X direction and the Z direction are arranged so as to penetrate in the plate thickness direction. Since such a flat support is disposed along the flow direction of the cooling air, the support is prevented from inhibiting the inflow and outflow of the cooling air. On the other hand, the support disposed in the ventilation portion 33 is configured in a band plate shape having a predetermined width in the X direction and extending in the Z direction so as to connect the heat transfer tubes 2 arranged in the Z direction to each other, for example. The strip-shaped support can also avoid obstructing the flow of the cooling air in the ventilation portion 33. Since this heat exchanger 1 uses the flat heat transfer tube 2 as described above, the strength of the joint portion between the distribution portion 11 and each heat transfer tube 2 and the joint portion between the gathering portion 12 and each heat transfer tube 2. However, the resonance state of the heat transfer tube 2 is also different from that of the conventional tube heat exchanger tube due to the fact that the flat tube and the circular tube have different cross-sectional shapes. It is even more important to properly support the heat transfer tube 2.

  Next, the results of analyzing the flow around the heat exchanger composed of circular heat transfer tubes and the heat exchanger composed of flat heat transfer tubes will be examined. FIG. 5 shows an example of the result of CFD analysis of the flow around the heat exchanger. FIG. 5A shows the flow field when the heat transfer tube is formed of a circular tube, and FIG. Shows the state of the flow field when the heat transfer tube is constituted by a flat tube. FIG. 5 is drawn with the top and bottom reversed from FIG. In FIGS. 2A and 2B, the outer shape of the heat exchanger is set to be substantially the same, and the arrangement pitch of the heat transfer tubes is also set to be substantially the same. For this reason, the same figure (a) and (b) differs in the magnitude | size of the clearance gap between adjacent heat exchanger tubes in the main-body part of a heat exchanger, and the heat exchanger which consists of a flat tube (the figure (b)). Is higher in ventilation rate than a heat exchanger composed of a circular tube (FIG. 1A). In the figure, “High” indicates a region where the flow velocity is relatively high, “Low” indicates a region where the flow velocity is relatively low, and “Medium” indicates a region where the flow velocity is intermediate. .

  First, as shown in FIG. 3A, in the heat exchanger in which the main body portion 3 is constituted by a circular heat transfer tube, the inflow end of the inflow portion (the right end portion of the main body portion indicated by reference numeral 3 in the same drawing). Although the flow velocity increases in the vicinity, the flow velocity decreases from the downstream side of the inflow portion to the ventilation portion. In particular, on the inner side in the vehicle width direction (lower side in the figure), the low flow velocity region widens widely from the ventilation portion to the outflow portion, and the wake region of the outflow portion is a low flow velocity region.

  On the other hand, as shown in the same figure (b), in the heat exchanger in which the main body part 3 is constituted by the heat transfer tube made of a flat tube, the state where the flow velocity is high from the inflow portion to the ventilation portion is maintained as it is. In the outer portion of the main body portion 3 in the vehicle width direction, the high flow velocity region extends over the entire area of the inflow portion, the ventilation portion, and the outflow portion. Along with this, the region of low flow velocity has become significantly smaller.

  In the CFD analysis results, when the inlet flow velocity of the main body 3 is the same at 5.4 m / s in FIGS. 5A and 5B, the outlet flow velocity is 3.0 m / s in FIG. In FIG. 5B, it was 3.9 m / s, and it was confirmed that a decrease in the flow velocity was suppressed by using a heat transfer tube made of a flat tube. In addition, the heat radiation amount was 28 kW in the same figure (a), and 32 kW in the same figure (b), and it was confirmed that the heat exchanger using the heat transfer tube made of a flat tube has higher heat radiation efficiency. Employing a heat transfer tube made of a flat tube in this way is advantageous in improving heat exchange efficiency by avoiding an increase in pressure loss.

  The aspect ratio a / b (see FIG. 4A) of the cross section of the flat tube used for the heat transfer tube 2 is preferably 2 <a / b <10. FIG. 6 shows the relationship between the aspect ratio a / b of the cross section of the flat tube and the resonance frequency (natural frequency) of the flat tube. The resonance frequency indicates the resonance frequency at 120 km / h included in the speed range of the railway vehicle on which the heat exchanger 1 is mounted, in other words, in the flow velocity range of the traveling wind. The resonance frequency decreases as the aspect ratio a / b decreases. The frequency is high. Here, the frequency of the Karman vortex generated when the traveling wind passes through the main body 3 (exactly around the heat transfer tube) is 250 Hz at a flow velocity of 120 km / h. In order to avoid resonance, it is desirable to set the aspect ratio a / b to less than 10. Avoiding resonance of the heat transfer tube 2 in this way makes it possible to omit reinforcement of the heat transfer tube 2 and is advantageous for reducing the weight of the heat exchanger 1.

  FIG. 7 shows the relationship between the aspect ratio of the cross section of the flat tube (heat transfer tube) and the pressure loss of the main body 3, where the outer shape of the main body 3 is constant and the pitch of the heat transfer tubes is constant. Then, changes in pressure loss when the aspect ratio a / b of the cross section of the heat transfer tube is changed are shown. According to the figure, the pressure loss increases when the aspect ratio a / b is close to 1, and particularly when the aspect ratio a / b is 2 or less, the pressure loss increases rapidly. For this reason, the aspect ratio a / b can be set to be larger than 2 in order to secure the flow rate of the traveling wind passing through the inside of the main body 3 to a necessary amount or more and achieve a desired heat exchange efficiency. preferable.

  From the above results, in the heat exchanger 1 mounted on a railway vehicle, it is desirable to set the cross-sectional shape of the heat transfer tube 2 made of a flat tube to 2 <a / b <10.

  Such a heat transfer tube 2 can be made of various materials, but considering its workability, it is preferably made of aluminum or an aluminum alloy.

  Here, FIG. 8 shows the state of the flow field when vehicle members are arranged before and after the heat exchanger 1, as shown in FIG. Since such a vehicle member generates a vortex in front of the inflow portion of the heat exchanger, the dynamic pressure on the upstream side of the inflow portion decreases, which is disadvantageous for the inflow of traveling wind, as described above, The main body part 3 constituted by the heat transfer tube 2 made of a flat tube has a large opening area at the inflow end (in other words, a high ventilation rate), and the traveling wind easily flows in. Therefore, the vehicle width direction (Y It is possible to allow the flow bent from the outside to the inside to flow into the main body 3 as it is. That is, as shown in FIG. 2, the heat exchanger 1 described above effectively captures the traveling wind and suppresses a decrease in heat exchange efficiency even when the vehicle member 93 is disposed before and after the heat exchanger 1.

  FIG. 9 shows a modification of the heat transfer tube 2, and in this example, the turbulent flow promoting member 4 is attached to the peripheral surface of the heat transfer tube 2 made of a flat tube. As shown in FIG. 9A, the turbulent flow promoting member 4 is a curved piece-like member provided so as to protrude from the peripheral surface of the heat transfer tube 2, and is conceptually shown in FIG. As shown in FIG. 5, a vertical vortex is generated, thereby promoting the turbulence of the flow in the main body 3.

  Specifically, in the illustrated example, a plurality of first heat transfer tubes 2 constituting the inflow portion 31 are formed at predetermined intervals in the tube axis direction. However, the heat transfer tube 2 to which the turbulent flow promoting member is attached is the heat transfer tube 2 from the inflow end (the right end of FIG. 9B) to the third row at the inflow portion 31 to obtain a sufficient turbulent flow promotion effect. However, the pressure loss is prevented from increasing excessively. Further, the turbulent flow promoting member 4 is attached so as to face each other between the adjacent heat transfer tubes 2 in the heat transfer tubes 2 arranged in a square lattice shape, and the facing portions are set to be staggered. Has been. The shape, the number of attachments, the attachment position, etc. of the turbulent flow promoting member 4 can be set as appropriate.

  Since the turbulent flow promoting member 4 promotes the turbulent flow in the main body 3 as described above, it is advantageous for improving the heat exchange efficiency.

  In addition, the flat heat exchanger tube 2 is not limited to the shape of the example of illustration, What is necessary is just a shape containing a major axis and a minor axis orthogonal to it. For example, an elliptic tube having an elliptical cross section may be employed.

  In addition, the arrangement of the heat transfer tubes 2 is not limited to a square lattice shape, and the main body portion may be configured by arranging at least a plurality of heat transfer tubes at intervals. Moreover, in the said structure, in the inflow end in the inflow part 31, and the outflow end in the outflow part 32, the several heat exchanger tubes 2 are arranged in a line in the Z direction, and the inflow end in the inflow part 31 and the outflow part 32 are arranged. Although the outflow end in each is configured to have a planar shape expanding on the XY plane, the configuration of the inflow end and the outflow end is not limited to this. For example, the heat transfer tubes 2 may be arranged in a staggered manner in the Z direction at the inflow end and the outflow end as viewed along the Y direction (as viewed in the direction shown in FIG. 1). Further, at the inflow end and the outflow end, the positions of the inflow end and the outflow end may be inclined by sequentially changing the positions of the plurality of heat transfer tubes 2 in the X direction as they proceed in the Z direction. Furthermore, at the inflow end and the outflow end, only some of the heat transfer tubes 2 may be arranged with their positions shifted in the X direction with respect to the other heat transfer tubes 2. There is no limitation on the number of heat transfer tubes. Furthermore, the shape of the main body 3 is not limited to a rectangular shape in plan view as shown in FIG. For example, the shape of the main body 3 may be a trapezoidal shape or the like in plan view by appropriately setting the angles of two bent portions in each heat transfer tube 2.

  In addition, the vehicle on which the heat exchanger 1 is mounted is not limited to a railway vehicle such as a Shinkansen, a conventional line (including a private railway line), and a subway line, and for example, travels on a track such as a monorail or a tram The vehicle may be mounted on a trackless vehicle such as a vehicle, a passenger car, a bus, or a truck. In addition, the target fluid of the heat exchanger 1 is not limited to insulating oil, and various fluids can be cooled by running wind.

  As described above, the heat exchanger disclosed herein can increase the heat exchange efficiency without causing an increase in size, so that it can be used in addition to railway vehicles (Shinkansen, conventional lines, subway lines, etc.). In addition, for example, the present invention can be widely applied as a traveling wind self-cooling heat exchanger mounted on a vehicle traveling on a track such as a monorail or a streetcar, or on a trackless vehicle such as a passenger car, bus or truck.

DESCRIPTION OF SYMBOLS 1 Heat exchanger 11 Distribution part 12 Aggregation part 2 Heat transfer tube 3 Main-body part 31 Inflow part 32 Outflow part 33 Ventilation part 4 Turbulence promotion member 91 Railway vehicle (vehicle)

Claims (4)

A heat exchanger mounted on a vehicle and configured to dissipate a target fluid flowing in a plurality of heat transfer tubes by passing cooling air flowing in a predetermined direction,
A distribution unit configured to distribute the target fluid to the plurality of heat transfer tubes while the target fluid is introduced;
A collecting portion that is arranged at an interval in the flow direction of the cooling air with respect to the distributing portion, and is configured to collect and discharge the target fluid flowing from the plurality of heat transfer tubes;
The plurality of heat transfer tubes formed to communicate with the distribution unit and the collecting unit are arranged side by side with a space therebetween, and the cooling air passes between the heat transfer tubes. A main body, and
The main body is
The heat transfer tube portion extends from the distribution portion or the collecting portion so as to intersect the flow direction of the cooling air, and a plurality of the heat transfer tube portions are arranged in a direction orthogonal to the flow direction of the cooling air. An inflow portion for allowing the traveling wind to flow into the main body portion via an inflow end disposed;
The heat transfer tube portion extends from the assembly portion or the distribution portion so as to intersect the flow direction of the cooling air, and a plurality of the heat transfer tube portions are arranged in a direction perpendicular to the flow direction of the cooling air. An outflow portion for allowing the traveling wind to flow out of the main body portion through the arranged outflow end;
A ventilation portion that is configured by a portion of the heat transfer tube extending along the flow direction of the cooling air and that flows the cooling air flowing in from the inflow portion toward the outflow portion along the heat transfer tube. And
The heat transfer tube has a flat cross-sectional shape including a major axis and a minor axis perpendicular thereto at the inflow portion and the outflow portion, and the direction of the major axis is the flow direction of the cooling air. A heat exchanger arranged in a direction along. The heat exchanger according to claim 1,
The heat transfer tube is bent in a U shape so as to continuously constitute the inflow portion, the outflow portion, and the ventilation portion,
The U-shaped heat transfer tube has a flat cross-sectional shape including the major axis and the minor axis, thereby having an enlarged heat transfer surface that extends in the direction of the major axis,
The U-shaped heat transfer tubes are also arranged in parallel from the inside to the outside of the vehicle, which are orthogonal to the flow direction of the cooling air, so that the expanded heat transfer surface of each heat transfer tube Constitutes a heat transfer tube group arranged along the flow direction of the cooling air,
The main body portion is configured by stacking a plurality of the heat transfer tube groups with a predetermined gap therebetween, and thereby, between the adjacent heat transfer tube groups, the expanded heat transfer surface of each heat transfer tube. The heat exchanger in which the flow path of the cooling air sandwiched is formed so as to extend straight in the flow direction of the cooling air. The heat exchanger according to claim 1 or 2,
The heat exchanger tube is a heat exchanger configured such that a ratio (a / b) between the length a of the major axis and the length b of the minor axis is 2 <a / b <10. The heat exchanger according to any one of claims 1 to 3,
In the inflow portion, at least the heat transfer tube disposed on the cooling air inflow side is provided with a turbulence promoting member that promotes turbulence of the cooling air flowing into the main body on the peripheral surface thereof. Heat exchanger.

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