heat exchanger

Abstract

To provide a heat exchanger that can suppress the increase in airflow pressure loss in heat exchangers used in aircraft. [Solution] This heat exchanger 100 is positioned upstream of the circular pipe 10 in the airflow direction (X direction), has a shape that tapers from the downstream side (X2 side) to the upstream side (X1 side) in the airflow direction (X direction), and includes an upstream flow adjustment member 20 that adjusts the direction of the airflow.

Description

Technical Field

[0001] This invention relates to a heat exchanger.

Background Art

[0002] Conventionally, a heat exchanger for an aircraft that performs heat exchange with an air flow and includes a circular pipe through which a fluid to be heat-exchanged flows is known (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Here, although not specified in Patent Document 1 above, when a heat exchanger as described in Patent Document 1 above is used in an aircraft, due to the very high speed of the air flow around the circular pipe, the pressure loss (energy loss) of the air flow in the heat exchanger is large. In that case, it causes a decrease in the flight performance and fuel efficiency of the aircraft. Therefore, a heat exchanger capable of suppressing an increase in the pressure loss of the air flow in a heat exchanger used in an aircraft is desired.

[0005] This invention has been made to solve the above problems, and one object of this invention is to provide a heat exchanger capable of suppressing an increase in the pressure loss of the air flow in a heat exchanger used in an aircraft.

Means for Solving the Problems

[0006] To achieve the above objective, the heat exchanger according to the first aspect of this invention is a heat exchanger for an aircraft that exchanges heat with an airflow, comprising a circular pipe through which a fluid to be heat exchanged flows, and an upstream flow adjusting member that adjusts the direction of the airflow, which is positioned upstream of the circular pipe in the direction of airflow, and whose upstream portion in the direction of airflow has a shape that tapers from the downstream side to the upstream side in the direction of airflow.

[0007] Furthermore, in order to achieve the above objective, a heat exchanger according to a second aspect of this invention is a heat exchanger for an aircraft that exchanges heat with an airflow, comprising a pipe through which a fluid to be heat exchanged flows, and an upstream flow adjusting member that adjusts the direction of the airflow, which is positioned upstream of the pipe in the direction of airflow, and whose upstream portion in the direction of airflow has a shape that tapers from the downstream side to the upstream side in the direction of airflow. [Effects of the Invention]

[0008] According to the present invention, it is possible to suppress the increase in pressure loss of the airflow in a heat exchanger used in an aircraft. [Brief explanation of the drawing]

[0009] [Figure 1] This diagram shows the configuration of a heat exchanger according to an embodiment of the present invention, viewed from a direction perpendicular to the direction in which the circular tube extends and the direction of airflow. [Figure 2] This is a view of the configuration of a heat exchanger according to an embodiment of the present invention, as seen from the direction in which the circular tube extends. [Figure 3] This is an enlarged view of an upstream flow adjustment member according to an embodiment of the present invention. [Figure 4] This is a distribution diagram of Mach numbers in the simulation results regarding the heat exchange rate of the heat exchanger in the comparative example. [Figure 5]This is a distribution diagram of Mach numbers in a simulation result relating to a heat exchanger according to an embodiment of the present invention, where the distance between the circular pipe and the upstream flow adjustment member is 0, and the inclination angle of the hypotenuse of the triangular-shaped upstream flow adjustment member with respect to the airflow direction is 30 degrees. [Figure 6] This is a distribution diagram of Mach numbers in a simulation result relating to a heat exchanger according to an embodiment of the present invention, where the distance between the circular pipe and the upstream flow adjustment member is 0.5 times the diameter of the circular pipe, and the inclination angle of the hypotenuse of the triangular-shaped upstream flow adjustment member with respect to the airflow direction is 10 degrees. [Figure 7] This is a distribution diagram of Mach numbers in a simulation result relating to a heat exchanger according to an embodiment of the present invention, where the distance between the circular pipe and the upstream flow adjustment member is 1 times the diameter of the circular pipe, and the inclination angle of the hypotenuse of the triangular-shaped upstream flow adjustment member with respect to the airflow direction is 10 degrees. [Figure 8] This graph shows the relationship between the distance between the circular pipe and the upstream flow adjustment member and the pressure loss in a simulation result relating to a heat exchanger according to an embodiment of the present invention. [Figure 9] This graph shows the relationship between the inclination angle of the hypotenuse of the triangular-shaped upstream flow adjustment member with respect to the airflow direction and the pressure loss, in the simulation results for a heat exchanger according to an embodiment of the present invention. [Figure 10] This graph shows the relationship between the distance between the circular pipe and the upstream flow adjustment member and the amount of heat exchanged, based on simulation results for a heat exchanger according to an embodiment of the present invention. [Figure 11] This graph shows the relationship between the inclination angle of the hypotenuse of the triangular-shaped upstream flow adjustment member with respect to the airflow direction and the amount of heat exchanged, in the simulation results for a heat exchanger according to an embodiment of the present invention. [Figure 12] This is a view of the configuration of a heat exchanger according to the first modified example of the present invention, as seen from the direction in which the circular tube extends. [Figure 13] This is a view of the configuration of a heat exchanger according to a second modified example of the present invention, as seen from the direction in which the circular tube extends.

Best Mode for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present invention will be described based on the drawings.

[0011] Referring to FIGS. 1 to 3, the configuration of a heat exchanger 100 according to an embodiment of the present invention will be described. The heat exchanger 100 is an aircraft heat exchanger that performs heat exchange with an air flow. The heat exchanger 100 can be used in any place where an air flow occurs in an aircraft.

[0012] (Round tube) As shown in FIG. 1, the heat exchanger 100 includes a round tube 10 through which a fluid to be heat-exchanged flows. That is, the heat exchanger 100 is an air heat exchanger that performs heat exchange between the fluid flowing inside the round tube 10 and the air around the round tube 10. The fluid flowing inside the round tube 10 is, for example, hydrogen, fluorocarbon, hydrocarbon, water, or hydraulic oil. The round tube 10 is preferably formed using a metal material having high thermal conductivity such as aluminum, copper, brass, or the like.

[0013] A plurality (three) of the round tubes 10 are arranged side by side along the flow direction (X direction) of the air flow. Specifically, the round tubes 10 include a round tube 11, a round tube 12, and a round tube 13. And, from the upstream side (X1 side) to the downstream side (X2 side) in the flow direction of the air flow, the round tube 11, the round tube 12, and the round tube 13 are arranged in this order along the flow direction (X direction) of the air flow. Each of the plurality of round tubes 10 extends in the Z direction orthogonal to the flow direction (X direction) of the air flow. Each of the plurality of round tubes 10 is sandwiched between a pair of headers extending in the flow direction (X direction) of the air flow.

[0014] In the following description, the flow direction of the air flow is taken as the X direction, the upstream side and the downstream side in the flow direction of the air flow are taken as the X1 side and the X2 side, respectively. Also, the direction in which the round tube 10 extends is taken as the Z direction. Also, the direction orthogonal to the flow direction of the air flow and the direction in which the round tube 10 extends is taken as the Y direction, and one side and the other side in the Y direction are taken as the Y1 side and the Y2 side, respectively.

[0015] (Upstream flow regulating member) As shown in FIG. 2, the heat exchanger 100 is disposed on the upstream side (X1 side) in the air flow direction (X direction) with respect to the circular tube 11 (circular tube 10), and has a triangular shape that tapers from the downstream side (X2 side) to the upstream side (X1 side) in the air flow direction (X direction), and includes an upstream flow regulating member 20 that adjusts the air flow direction. Note that the width W of the base (extending in the Y direction) of the upstream flow regulating member 20 having a triangular shape is smaller than the diameter D of the circular tube 10.

[0016] The hypotenuse 20a of the upstream flow regulating member 20 having a triangular shape extends in an oblique direction toward the direction between the tangential direction of the circular tube 11 (circular tube 10) and the air flow direction (X direction). For example, the hypotenuse 20a of the upstream flow regulating member 20 having a triangular shape extends so as to be 10 degrees or more and 20 degrees or less with respect to the air flow direction (X direction).

[0017] The upstream flow regulating member 20 is set such that the distance L between the circular tube 11 (circular tube 10) in the air flow direction (X direction) is set so that the hypotenuse 20a of the upstream flow regulating member 20 having a triangular shape extends in an oblique direction toward the direction between the tangential direction of the circular tube 11 (circular tube 10) and the air flow direction (X direction). Note that in FIG. 2, as an example, an example in which the distance L is set to the diameter D of the circular tube 10 is shown.

[0018] The upstream flow regulating member 20 has a triangular shape (isosceles triangular shape) that tapers from the downstream side (X2 side) to the upstream side (X1 side) in the air flow direction (X direction) and is symmetric with respect to the air flow direction (X direction) when viewed from the direction (Z direction) in which the circular tube 10 extends.

[0019] As shown in FIG. 3, the upstream flow regulating member 20 has a triangular shape that tapers from the downstream side (X2 side) to the upstream side (X1 side) in the air flow direction (X direction) and the tip 20b has a rounded shape.

[0020] As shown in Figure 1, the fluid to be subjected to heat exchange is also circulated through the upstream flow regulating member 20. That is, the same fluid that flows inside the circular pipe 10 flows inside the upstream flow regulating member 20, and heat exchange takes place between the fluid flowing inside the upstream flow regulating member 20 and the air surrounding the upstream flow regulating member 20. The upstream flow regulating member 20 is preferably formed from a metal material with high thermal conductivity, such as aluminum, copper, or brass, similar to the circular pipe 10.

[0021] (Downstream flow adjustment member) As shown in Figure 2, the heat exchanger 100 is positioned downstream (X2 side) of the circular pipe 13 (circular pipe 10) in the airflow direction (X direction), has a shape that tapers from the upstream side (X1 side) to the downstream side (X2 side) in the airflow direction (X direction), and includes a downstream flow adjustment member 30 that adjusts the direction of the airflow.

[0022] The shape of the downstream flow adjustment member 30 and its arrangement relative to the circular pipe 13, as well as the shape of the upstream flow adjustment member 20 and its arrangement relative to the circular pipe 11, are in a reversed relationship between the upstream side (X1 side) and the downstream side (X2 side) in the airflow direction (X direction).

[0023] As shown in Figure 1, the fluid to be subjected to heat exchange is also circulated through the downstream flow regulating member 30. That is, the same fluid that flows inside the circular pipe 10 flows inside the downstream flow regulating member 30, and heat exchange takes place between the fluid flowing inside the downstream flow regulating member 30 and the air surrounding the downstream flow regulating member 30. The downstream flow regulating member 30 is preferably formed from a metal material with high thermal conductivity, such as aluminum, copper, or brass, similar to the circular pipe 10.

[0024] (Simulation results) The simulation results for the heat exchanger 100 according to an embodiment of the present invention will be explained with reference to Figures 4 to 11.

[0025] The simulation calculated the distribution of Mach numbers near the circular pipe, the pressure loss of the airflow in the heat exchanger, and the amount of heat exchanged by the heat exchanger. The simulation performed a three-dimensional steady-state calculation of compressibility using the SST-K-ω turbulence model in the Reynolds-meaned Navier-Stokes equations. The simulation was performed under the following conditions: Air was assumed to be an ideal gas. Assuming use in an aircraft flying at high altitudes, the static pressure was set to -81060.0 Pa gauge pressure, the temperature to 20°C, and the total temperature and mass flow rate upstream were set according to the Mach number. The Mach number is the ratio of the airflow velocity to the speed of sound. The circular pipe was assumed to be made of aluminum, with a density of 2702.0 kg / m³. 3 The thermal conductivity was set to 237.0 W / (m·K). The fluid flowing inside the circular pipe was omitted. That is, the calculation was performed with temperature constraints around the circular pipe. The temperature of the circular pipe was set to 150°C. It was assumed that only one circular pipe was placed along the direction of airflow. The predetermined relationship that the pressure loss and heat exchange rate of the above embodiment must satisfy was derived based on the calculation results of this simulation. The simulation results are described below.

[0026] As shown in Figures 4 to 7, when an upstream flow adjustment member is arranged as in the heat exchanger according to this embodiment (Figures 5 to 7), the Mach number near the circular pipe is relatively larger compared to when an upstream flow adjustment member is not arranged as in the heat exchanger according to the comparative example (Figure 4). This confirms that the upstream flow adjustment member reduces the pressure loss of the airflow due to the heat exchanger. Note that Figures 4 to 7 show the distribution of Mach numbers only on one side in the direction perpendicular to the airflow direction.

[0027] As shown in Figures 8 and 9, it was confirmed that, generally, regardless of the distance L in the airflow direction between the circular pipe and the upstream flow regulating member, the pressure loss of the airflow in the heat exchanger increases as the angle of inclination of the hypotenuse of the triangular-shaped upstream flow regulating member with respect to the airflow direction increases, when the distance L in the airflow direction between the circular pipe and the upstream flow regulating member is in the range of 0.5D to 3.0D, and the angle of inclination of the hypotenuse of the triangular-shaped upstream flow regulating member with respect to the airflow direction increases.

[0028] As shown in Figures 10 and 11, when the distance L in the airflow direction between the circular pipe and the upstream flow adjustment member is in the range of 0.5D to 3.0D, it was confirmed that the amount of heat exchanged by the heat exchanger is generally greater when the angle of inclination of the hypotenuse of the triangular-shaped upstream flow adjustment member with respect to the airflow direction is 10 degrees and 20 degrees, compared to when the angle of inclination of the hypotenuse of the triangular-shaped upstream flow adjustment member with respect to the airflow direction is 0 degrees, 30 degrees, and 40 degrees.

[0029] Based on the above simulation results, it was found that, in order to suppress a decrease in the heat exchange performance in the heat exchanger 100 while suppressing an increase in the pressure loss of the airflow in the heat exchanger 100, the inclination angle of the hypotenuse of the triangular upstream flow adjustment member with respect to the airflow direction is preferably 10 degrees or more and less than 20 degrees.

[0030] (modified version) Furthermore, the embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive.

[0031] As shown in the first modified example of the heat exchanger 200 in Figure 12, the upstream flow adjustment member 220 may include an upstream portion 221 having a triangular shape that tapers from downstream to upstream in the airflow direction, and a downstream portion 222 having a shape that does not taper from downstream to upstream in the airflow direction. Alternatively, the upstream flow adjustment member may have a non-triangular shape that tapers from downstream to upstream in the airflow direction.

[0032] Furthermore, as shown in the second modified example of the heat exchanger 300 in Figure 13, the hypotenuse 320a of the triangular-shaped upstream flow adjustment member 320 may extend in a direction tangential to the circular pipe 10.

[0033] Furthermore, the hypotenuse of the triangular-shaped upstream flow adjustment member may extend at an angle of less than 10 degrees or 20 degrees or more with respect to the direction of airflow.

[0034] Furthermore, the upstream flow adjustment member may have a triangular shape that tapers from the downstream to the upstream side in the direction of airflow and is asymmetrical with respect to the direction of airflow.

[0035] Furthermore, the upstream flow adjustment member may have a triangular shape that tapers from the downstream side to the upstream side in the direction of airflow, with a pointed tip.

[0036] Furthermore, it is not necessary to pass the fluid to be heat-exchanged through the upstream flow adjustment member.

[0037] Furthermore, the heat exchanger is positioned downstream of the circular pipe in the direction of airflow, has a shape that tapers from the upstream to the downstream side in the direction of airflow, and does not need to be equipped with a downstream flow adjustment member to adjust the direction of airflow.

[0038] Furthermore, there may be only one circular pipe arranged along the direction of airflow. Alternatively, two or more circular pipes may be arranged in a line along the direction of airflow. Alternatively, multiple circular pipes may be arranged in a line perpendicular to the direction of airflow. Alternatively, multiple circular pipes may be arranged in a line along the direction of airflow, and multiple circular pipes arranged along the direction of airflow may be arranged in a line perpendicular to the direction of airflow.

[0039] Furthermore, the shape of the downstream flow adjustment member and its arrangement relative to the downstreammost circular pipe among the multiple circular pipes of the downstream flow adjustment member in the direction of airflow, and the shape of the upstream flow adjustment member and its arrangement relative to the upstreammost circular pipe among the multiple circular pipes of the upstream flow adjustment member in the direction of airflow, do not necessarily have to be inverted relationships between the upstream and downstream sides in the direction of airflow.

[0040] Furthermore, it is not necessary to pass the fluid to be heat-exchanged through the downstream flow adjustment member.

[0041] Furthermore, the pipe through which the fluid to be heat exchanged flows may be a pipe other than the circular pipe 10 (a pipe with a cross-sectional shape other than a circular shape). However, at least one of the ends of the pipe, one in the direction perpendicular to the airflow direction (X direction) and the direction in which the pipe extends (Z direction) (Y direction) (Y direction), and the other in the vicinity of the end on the other side (Y2 side), shall have a curved shape. Note that the term "near the end" includes both the end itself and the vicinity of the end.

[0042] (Effects of this embodiment) According to this embodiment or its modifications, the following effects can be obtained.

[0043] In this embodiment, as described above, the heat exchanger 100 is positioned upstream of the circular pipe 10 in the airflow direction and includes an upstream flow adjustment member 20 that tapers from downstream to upstream in the airflow direction and adjusts the direction of the airflow. As a result, in the heat exchanger 100 used in an aircraft, the upstream flow adjustment member 20, which has a shape that tapers from downstream to upstream in the airflow direction, can suppress turbulence in the airflow upstream of the circular pipe 10 in the airflow direction. Consequently, compared to the case where the upstream flow adjustment member 20 is not positioned downstream of the circular pipe 10 in the airflow direction, it is possible to suppress an increase in the pressure loss of the airflow in the heat exchanger 100 used in an aircraft.

[0044] Furthermore, in this embodiment, as described above, the upstream flow adjustment member 20 has a triangular shape that tapers from the downstream side to the upstream side in the direction of airflow. This makes it easy to realize a configuration in which the upstream flow adjustment member 20 has a shape that tapers from the downstream side to the upstream side in the direction of airflow.

[0045] Furthermore, in this embodiment, as described above, the hypotenuse 20a of the triangular upstream flow adjustment member 20 extends in an oblique direction between the direction tangential to the circular pipe 10 and the direction of airflow. This makes it possible to suppress a decrease in the flow rate per unit time of the airflow toward the circular pipe 10 by adjusting the flow direction with the upstream flow adjustment member 20, compared to the case where the hypotenuse 20a of the triangular upstream flow adjustment member 20 extends toward the direction in which the circular pipe 10 is not located. As a result, it is possible to suppress a decrease in the heat exchange performance in the heat exchanger 100 while suppressing an increase in the pressure loss of the airflow in the heat exchanger 100, compared to the case where the hypotenuse 20a of the triangular upstream flow adjustment member 20 extends toward the direction in which the circular pipe 10 is not located.

[0046] Furthermore, in this embodiment, as described above, the distance L between the upstream flow adjustment member 20 and the circular pipe 10 in the direction of airflow is set such that the hypotenuse 20a of the triangular-shaped upstream flow adjustment member 20 extends in an oblique direction between the direction tangential to the circular pipe 10 and the direction of airflow. This makes it easy to realize a configuration in which the hypotenuse 20a of the triangular-shaped upstream flow adjustment member 20 extends in an oblique direction between the direction tangential to the circular pipe 10 and the direction of airflow.

[0047] Furthermore, in this embodiment, as described above, the hypotenuse 20a of the triangular upstream flow adjustment member 20 extends at an angle of 10 degrees or more and 20 degrees or less with respect to the airflow direction. As a result, as found in the simulation results above, compared to the case where the hypotenuse 20a of the triangular upstream flow adjustment member 20 extends at an angle of less than 10 degrees or 20 degrees or more with respect to the airflow direction, it is possible to suppress a decrease in the heat exchange performance in the heat exchanger 100 while suppressing an increase in the pressure loss of the airflow in the heat exchanger 100.

[0048] Furthermore, in this embodiment, as described above, the upstream flow adjustment member 20 tapers from the downstream to the upstream side in the airflow direction and has a triangular shape symmetrical with respect to the airflow direction. This makes it possible to suppress the complexity of the design of the upstream flow adjustment member 20, such as the direction in which the hypotenuse 20a of the triangular-shaped upstream flow adjustment member 20 extends, compared to the case in which the upstream flow adjustment member 20 has an asymmetrical triangular shape with respect to the airflow direction.

[0049] Furthermore, in this embodiment, as described above, the upstream flow adjustment member 20 has a triangular shape that tapers from the downstream side to the upstream side in the direction of airflow, and has a rounded tip 20b. This improves the strength of the tip 20b of the upstream flow adjustment member 20 against the airflow compared to the case where the tip 20b of the upstream flow adjustment member 20 is pointed and not rounded.

[0050] Furthermore, in this embodiment, as described above, the fluid to be heat exchanged is also flowed through the upstream flow adjustment member 20. This increases the amount of heat exchanged in the heat exchanger 100 because heat exchange also takes place in the upstream flow adjustment member 20. As a result, the heat exchange performance in the heat exchanger 100 can be improved compared to the case where the fluid to be heat exchanged is not flowed through the upstream flow adjustment member 20.

[0051] Furthermore, in this embodiment, as described above, the heat exchanger 100 is positioned downstream of the circular pipe 10 in the airflow direction and includes a downstream flow adjustment member 30 that tapers from the upstream to the downstream side in the airflow direction and adjusts the direction of the airflow. As a result, the downstream flow adjustment member 30, which has a shape that tapers from the upstream to the downstream side in the airflow direction, can suppress turbulence in the airflow downstream of the circular pipe 10 in the airflow direction. Consequently, it is possible to suppress an increase in the pressure loss of the airflow in the heat exchanger 100 compared to the case where the downstream flow adjustment member 30 is not positioned downstream of the circular pipe 10 in the airflow direction.

[0052] Furthermore, in this embodiment, as described above, multiple circular pipes 10 are arranged in a line along the direction of airflow. This increases the amount of heat exchanged in the heat exchanger 100 compared to the case where only one circular pipe 10 is arranged along the direction of airflow. Also, it reduces the pressure loss of the airflow in the heat exchanger 100 compared to the case where multiple circular pipes 10 are arranged in a line perpendicular to the direction of airflow. As a result, it is possible to improve the heat exchange performance in the heat exchanger 100 while suppressing an increase in the pressure loss of the airflow in the heat exchanger 100. [Explanation of Symbols]

[0053] 10(11, 12, 13) circular tube 20, 220, 320 Upstream flow adjustment member 20a, 320a (Hypotenuses of the upstream flow adjustment member) 20b (Tip of the upstream flow adjustment member) 30 Downstream flow adjustment member 100, 200, 300 heat exchanger L (in the direction of airflow) Distance between the upstream flow regulating member and the circular pipe

Claims

1. A heat exchanger for aircraft that exchanges heat with airflow, A circular pipe through which the fluid to be subjected to heat exchange flows, A heat exchanger comprising an upstream flow adjusting member, which is positioned upstream of the circular pipe in the direction of airflow and has a shape that tapers from the downstream to the upstream side in the direction of airflow, for adjusting the direction of airflow.

2. The heat exchanger according to claim 1, wherein the upstream flow adjustment member has a triangular shape that tapers from the downstream side to the upstream side in the direction of airflow.

3. The heat exchanger according to claim 2, wherein the hypotenuse of the upstream flow adjustment member having a triangular shape extends in a direction tangential to the circular pipe, or in an oblique direction between the direction tangential to the circular pipe and the flow direction of the airflow.

4. The heat exchanger according to claim 3, wherein the distance between the upstream flow adjusting member and the circular pipe in the direction of airflow is set such that the hypotenuse of the triangular-shaped upstream flow adjusting member extends in a direction that is tangent to the circular pipe, or in an oblique direction between the direction that is tangent to the circular pipe and the direction of airflow.

5. The heat exchanger according to claim 2, wherein the hypotenuse of the upstream flow adjustment member having the triangular shape extends at an angle of 10 degrees or more and 20 degrees or less with respect to the direction of airflow.

6. The heat exchanger according to claim 2, wherein the upstream flow adjustment member tapers from the downstream to the upstream side in the direction of the airflow and has a triangular shape symmetrical with respect to the direction of the airflow.

7. The heat exchanger according to claim 2, wherein the upstream flow adjustment member has a triangular shape that tapers from the downstream to the upstream side in the direction of the airflow and has a rounded tip.

8. The heat exchanger according to claim 1, wherein the fluid to be subjected to heat exchange is also passed through the upstream flow adjustment member.

9. The heat exchanger according to claim 1, further comprising a downstream flow adjusting member that is positioned downstream of the circular pipe in the direction of airflow, has a shape that tapers from the upstream to the downstream side in the direction of airflow, and adjusts the direction of airflow.

10. The heat exchanger according to claim 1, wherein the circular tubes are arranged in a row along the direction of the airflow.

11. A heat exchanger for aircraft that exchanges heat with airflow, A pipe through which the fluid to be heat exchanged flows, A heat exchanger comprising an upstream flow adjusting member, which is positioned upstream of the aforementioned pipe in the direction of airflow, and has a shape that tapers from the downstream to the upstream side in the direction of airflow, and which adjusts the direction of airflow.

12. The heat exchanger according to claim 11, wherein the upstream flow adjustment member has a triangular shape that tapers from the downstream side to the upstream side in the direction of airflow.

13. At least one of the ends of the tube, near one end in a direction perpendicular to the direction of airflow and the direction in which the tube extends, and near the other end, has a curved shape. The heat exchanger according to claim 12, wherein the hypotenuse of the upstream flow adjustment member having a triangular shape extends in a direction tangential to the pipe, or in an oblique direction between the direction tangential to the pipe and the flow direction of the airflow.

14. The heat exchanger according to claim 13, wherein the distance between the upstream flow adjusting member and the pipe in the direction of the airflow is set such that the hypotenuse of the triangular upstream flow adjusting member extends in a direction tangential to the pipe, or in an oblique direction between the direction tangential to the pipe and the direction of the airflow.

15. The heat exchanger according to claim 12, wherein the hypotenuse of the upstream flow adjustment member having the triangular shape extends at an angle of 10 degrees or more and 20 degrees or less with respect to the direction of airflow.

16. The heat exchanger according to claim 12, wherein the upstream flow adjustment member tapers from the downstream to the upstream side in the direction of the airflow and has a triangular shape symmetrical with respect to the direction of the airflow.

17. The heat exchanger according to claim 12, wherein the upstream flow adjustment member has a triangular shape that tapers from the downstream to the upstream side in the direction of the airflow and has a rounded tip.

18. The heat exchanger according to claim 11, wherein the fluid to be subjected to heat exchange is also passed through the upstream flow adjustment member.

19. The heat exchanger according to claim 11, further comprising a downstream flow adjusting member that is positioned downstream of the pipe in the direction of airflow, has a shape that tapers from the upstream to the downstream side in the direction of airflow, and adjusts the direction of airflow.

20. The heat exchanger according to claim 11, wherein the tubes are arranged in a row along the direction of the airflow.

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