CN111637492B

CN111637492B - Heat exchanger and miniature gas turbine

Info

Publication number: CN111637492B
Application number: CN202010484607.7A
Authority: CN
Inventors: 韩品连; 张坤
Original assignee: Shenzhen Yidong Aviation Technology Co Ltd
Current assignee: Shenzhen Yidong Aviation Technology Co Ltd
Priority date: 2020-06-01
Filing date: 2020-06-01
Publication date: 2021-10-22
Anticipated expiration: 2040-06-01
Also published as: CN111637492A

Abstract

The invention relates to the technical field of miniature combustion engines, and discloses a heat exchanger and a miniature combustion engine, wherein the heat exchanger comprises: the spiral flow passage is formed by surrounding two adjacent spiral sectors. The micro combustion engine comprises the heat exchanger. The heat exchanger provided by the invention adopts the plurality of spiral sectors arranged between the outer shell and the inner shell as the main heat exchange mechanism, so that the volume is smaller, and the heat exchange efficiency is higher. The micro-combustion engine provided by the invention adopts the heat exchanger, and has smaller volume, lower cost and higher thermal efficiency.

Description

Heat exchanger and miniature gas turbine

Technical Field

The invention relates to the field of miniature gas turbines, in particular to a heat exchanger and a miniature gas turbine.

Background

A micro-combustion engine is a turbine engine in the form of a back-flow combustor, which typically includes three major parts, a compressor, a combustor and a turbine. Usually, a heat exchanger is arranged outside a combustion chamber of the micro combustion engine and used for preheating intake air and reducing exhaust temperature, so that nitrogen oxide emission of the micro combustion engine is reduced, and the thermal efficiency of the turbine engine is improved.

The heat exchanger in the prior art is generally formed by stacking a plurality of spaced or nested heat exchange units, and has the disadvantages of complex structure, large volume, low heat exchange efficiency and large manufacturing and assembling difficulty. In order to realize larger heat exchange power, the heat exchanger generally increases the volume and weight of the heat exchanger by increasing the number of stacked heat exchange units, which obviously does not meet the use requirement of a micro-combustion engine.

Disclosure of Invention

Based on the above, the present invention provides a heat exchanger, so as to solve the technical problems of complex structure, large volume, low heat exchange efficiency, etc. of the heat exchanger in the prior art.

Another object of the present invention is to provide a micro-combustion engine using the above heat exchanger, which has a smaller volume, lower cost and higher thermal efficiency.

In order to achieve the purpose, the invention adopts the following technical scheme:

there is provided a heat exchanger comprising: the outer shell, the inner shell and the envelope are in the outer shell with a plurality of spiral sectors between the inner shell, the outer ends of the spiral sectors are connected with the outer shell, the other ends of the spiral sectors are spirally and inwardly connected with the inner shell in an encircling manner, and two adjacent spiral sectors surround a fluid flow channel forming a spiral shape.

As a preferred scheme of the heat exchanger, the fluid runners on two sides of the spiral sector are respectively a hot fluid runner and a cold fluid runner, and a plurality of the hot fluid runners and a plurality of the cold fluid runners are distributed at intervals;

one end of the hot fluid flow channel, facing the first end face of the heat exchanger, is open, and one end of the hot fluid flow channel, facing the second end face of the heat exchanger, is closed;

one end, facing the first end face, of the cold fluid flow channel is closed, and one end, facing the second end face, of the cold fluid flow channel is opened.

As a preferable scheme of the heat exchanger, one end of the inner shell, which is close to the first end face, is provided with a plurality of cold fluid outlets at equal intervals along the circumferential direction, and the plurality of cold fluid outlets are respectively communicated with the plurality of cold fluid runners;

and a plurality of hot fluid inlets are arranged at equal intervals along the circumferential direction at one end of the inner shell close to the second end surface, and are respectively communicated with the plurality of hot fluid flow channels.

As a preferable scheme of the heat exchanger, the plurality of spiral sectors are uniformly distributed along the circumferential direction of the heat exchanger, and the plurality of spiral sectors are arranged at equal intervals along the radial direction of the heat exchanger.

As a preferred solution of the heat exchanger, the thickness d of the spiral sector₁Between 0.25 and 1 mm.

As a preferred scheme of the heat exchanger, the number of the spiral sectors is between 20 and 30.

As a preferred embodiment of the heat exchanger, the fluid flow channel has a normal width d₂Is between 0.5 and 1 mm.

As a preferred variant of a heat exchanger, the radial width between the outer casing and the inner casing, i.e. the radial span d of the helical sector₃Between 20mm and 50 mm.

As a preferred scheme of the heat exchanger, the heat exchanger is integrally processed by a laser powder laying additive manufacturing technology.

A micro gas turbine comprises the heat exchanger in any scheme, the heat exchanger is sleeved outside a combustion chamber of the micro gas turbine and is used for exchanging heat between cold and hot fluids entering and exiting the combustion chamber.

The invention has the beneficial effects that:

the heat exchanger provided by the invention adopts the plurality of spiral sectors arranged between the outer shell and the inner shell as a main heat exchange mechanism, the spiral sectors are in a shape of a spiral from outside to inside, so that the volume of the heat exchanger can be reduced as much as possible, and the thickness of the spiral sectors can be reduced as much as possible, thereby greatly improving the heat exchange efficiency of the heat exchanger.

The micro-combustion engine provided by the invention adopts the heat exchanger, and has the advantages of smaller volume, lower cost, higher thermal efficiency and less emission and pollution.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the contents of the embodiments of the present invention and the drawings without creative efforts.

FIG. 1 is a first schematic structural diagram of a heat exchanger provided in an embodiment of the present invention;

FIG. 2 is a schematic structural diagram II of a heat exchanger provided in the embodiment of the present invention;

FIG. 3 is a cutaway isometric view of a heat exchanger provided in accordance with an embodiment of the present invention, taken along the line A-A in FIG. 1;

FIG. 4 is a schematic structural view of a single spiral sector of a heat exchanger provided by an embodiment of the present invention;

FIG. 5 is an enlarged view at E in FIG. 3;

FIG. 6 is a cross-sectional left side view of the heat exchanger of the present invention shown in FIG. 1, taken along the line A-A;

fig. 7 is an enlarged view at F in fig. 6:

FIG. 8 is a cutaway isometric view of a heat exchanger provided in accordance with an embodiment of the present invention, taken along the direction B-B in FIG. 2;

FIG. 9 is an enlarged view at G of FIG. 8;

FIG. 10 is a schematic structural diagram of a micro combustion engine provided in an embodiment of the present invention;

FIG. 11 is a cross-sectional view of a micro-combustion engine provided in accordance with an embodiment of the present invention;

FIG. 12 is a schematic view of the intake path of a micro-combustion engine provided in an embodiment of the present invention;

fig. 13 is a schematic view of an outlet path of a micro combustion engine provided in an embodiment of the present invention.

The figures are labeled as follows:

1. an outer housing; 2. an inner housing; 21. a cold fluid outlet; 22. a hot fluid inlet; 23. a baffle; 3. a spiral sector; 4. a fluid flow passage; 41. a hot fluid flow path; 42. a cold fluid flow channel; 5. a first end face; 51. a hot fluid outlet; 6. a second end face; 61. a cold fluid inlet;

100. a heat exchanger; 200. a micro gas turbine; 201. a compressor; 202. a combustion chamber; 203. a turbine.

Detailed Description

In order to make the technical problems solved, technical solutions adopted and technical effects achieved by the present invention clearer, the technical solutions of the embodiments of the present invention will be further described in detail with reference to the accompanying drawings, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, unless expressly stated or limited otherwise, the terms "connected," "connected," and "fixed" are to be construed broadly, e.g., as meaning permanently connected, removably connected, or integral to one another; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

In the description of the present embodiment, the terms "upper", "lower", "right", etc. are used in an orientation or positional relationship based on that shown in the drawings only for convenience of description and simplicity of operation, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used only for descriptive purposes and are not intended to have a special meaning.

As shown in fig. 1 to 9, the embodiment of the present invention provides a heat exchanger, which is mainly used for exchanging heat between the inlet and outlet gases of a micro combustion engine, so as to preheat the inlet gas and reduce the temperature of the outlet gas, thereby reducing the emission of nitrogen oxides and reducing the pollution to the environment. Of course, the heat exchanger provided in this embodiment may also be used in other heat engines with heat exchange requirements or other applications, and is not limited herein. The heat exchanger comprises a cylindrical outer shell 1, an inner shell 2 and a plurality of spiral sectors 3 enveloped between the outer shell 1 and the inner shell 2, wherein the outer ends of the spiral sectors 3 are connected to the outer shell 1, the inner ends of the spiral sectors are spirally and circularly connected to the inner shell 2 towards the inside, the spiral sectors 3 are arranged at equal intervals along the circumferential direction of the heat exchanger, and a spiral fluid flow channel 4 is formed between every two adjacent spiral sectors 3 in a surrounding manner. The fluid channels 4 on both sides of each spiral sector 3 are respectively a hot fluid channel 41 and a cold fluid channel 42, and the hot fluid and the cold fluid exchange heat through the spiral sectors 3.

The heat exchanger provided by the embodiment adopts the spiral sectors 3 arranged at equal intervals as the heat exchange structure, the spiral sectors 3 have large relative heat exchange area, and the thickness d of the spiral sectors 3₁Can be made as thin as possible to make the heat exchanger that this embodiment provided can reach high heat exchange efficiency, and its volume can accomplish to be as little as possible. Since the conventional material-reducing or material-waiting manufacturing technology cannot process the structure of the plurality of spiral sectors 3 arranged at intervals, the heat exchanger provided by the embodiment is preferably manufactured by using an additive manufacturing technology. More preferably, the heat exchanger is integrally manufactured and molded by adopting a laser powder laying additive manufacturing technology. The laser powder-laying additive manufacturing technology, also called as a laser 3D printing technology, has the characteristics of flexibility, easy realization of intellectualization, short production period, suitability for processing parts with complex structures, good mechanical properties of the produced parts and the like.

As shown in fig. 1 and 2, the present embodiment provides a heat exchanger having a first end face 5 and a second end face 6. The first end face 5 has a hot fluid outlet 51, the hot fluid outlet 51 is communicated with a plurality of hot fluid flow channels 41 enveloped between the outer shell 1 and the inner shell 2, and one end of the hot fluid flow channels 41 facing the second end face 6 is closed. The second end face 6 has a cold fluid inlet 61, the cold fluid inlet 61 is communicated with a plurality of cold fluid runners 42 enveloped between the outer shell 1 and the inner shell 2, and one end of the cold fluid runner 42 facing the first end face 5 is closed. A plurality of cold fluid outlets 21 which are arranged at equal intervals along the circumferential direction are formed in one end, close to the first end face 5 of the heat exchanger, of the inner surface of the inner shell 2, each cold fluid outlet 21 is communicated with one cold fluid runner 42, a plurality of hot fluid inlets 22 which are arranged at equal intervals along the circumferential direction are formed in one end, close to the second end face 6 of the heat exchanger, of the inner surface of the inner shell 2, and each hot fluid inlet 22 is communicated with one hot fluid runner 41.

In this embodiment, as a preferred scheme of the heat exchanger, sizes (i.e., areas) of the inlet and the outlet of the cold fluid inlet 61, the cold fluid outlet 21, the hot fluid inlet 22, and the hot fluid outlet 51 can be specifically adjusted according to heat exchange requirements such as heat exchange efficiency and pressure drop, so as to expand the application range and flexibility of the heat exchanger.

The cold fluid flows in from the cold fluid inlet 61 on the second end face 6 of the heat exchanger, then enters the plurality of cold fluid flow channels 42 inside the heat exchanger, flows spirally in the cold fluid flow channels 42, finally flows out from the plurality of cold fluid outlets 21 on the inner shell 2, and enters the combustion chamber of a micro-combustion engine or other heat engine. The hot fluid discharged from the combustion chamber of the micro-combustion engine or other heat engine enters the heat exchanger from the plurality of hot fluid inlets 22 on the inner housing 2 of the heat exchanger, then spirally flows along the plurality of hot fluid flow channels 41 inside the heat exchanger, and finally flows out of the heat exchanger through the hot fluid outlets 51 on the second end face 6 of the heat exchanger. The cold fluid and the hot fluid exchange heat through the spiral sector 3 in the flowing process in the heat exchanger, in the embodiment, along the radial direction of the heat exchanger, the cold fluid flows anticlockwise from outside to inside, the hot fluid flows clockwise from inside to outside, and the mode of the inside-outside reverse and cross flowing of the cold fluid and the hot fluid can realize the better heat exchange effect of the heat exchanger.

The internal structure of the first end face 5 side of the heat exchanger is shown in fig. 3-7. In the heat exchanger, a plurality of spiral sectors 3 are arranged at equal intervals from an outer shell 1 to an inner shell 2 along the radial direction of the heat exchanger, and the interval between two adjacent spiral sectors 3 is a fluid flow passage 4. To achieve a high heat exchange efficiency, the thickness d of the spiral sectors 3₁The smaller the size, the better, the present invention can achieve the thickness d of the spiral sector 3 by using additive manufacturing technology₁Of the spiral sectors 3, in order to ensure the structural strength of the heat exchangerThickness d₁A minimum limit should be set. In the present embodiment, optionally, the thickness d of the spiral sector 3₁Is set between 0.25 mm and 1 mm. Preferably, the thickness d of the helical sector 3₁Set at 0.5 mm.

To meet the heat exchange requirements of the heat exchanger, the spacing between the spiral sectors 3, i.e. the normal width d of the fluid flow channel 4₂Should be as small as possible and the normal width d of the fluid flow channel 4₂When too small, the fluid flow resistance increases. Alternatively, in the present embodiment, the normal width d of the fluid flow passage 4₂The thickness of the film is set between 0.5mm and 1 mm. Preferably, the fluid flow channel 4 has a normal width d₂Set at 0.5 mm.

Radial span d of the spiral sector 3₃Radial span d of the spiral sectors 3 for the radial distance of the heat exchanger from the outer casing 1 to the inner casing 2₃The larger the heat exchange area, the higher the heat exchange efficiency, but in a micro-combustion engine, d is due to volume limitations₃And may not be too large. In the present embodiment, optionally, the radial span d of the helicoidal sector 3₃Is set between 20mm and 50 mm. Preferably, the radial span d of the helical sector 3₃Set at 30.5 mm.

The number of the spiral sectors 3 is limited by the radial span d thereof₃And the inner diameter of the heat exchanger, in the embodiment, the number of the spiral sectors 3 is set between 20 and 30. Preferably, the number of the spiral sectors 3 is 24, and the 24 spiral sectors 3 are arranged at equal intervals along the circumferential direction of the heat exchanger, i.e. the circumferential included angle α between two adjacent spiral sectors 3 is 15 °. The 24 spiral sectors 3 enclose 24 fluid channels 4, 12 cold fluid channels 42 and hot fluid channels 41.

As a preferable scheme of the heat exchanger in this embodiment, the spiral sector 3 may be provided with protrusions or recesses having a circular shape, an oval shape, or other shapes, and the protrusions or recesses are uniformly distributed on the spiral sector 3, so as to increase the eddy current of the cold fluid and the hot fluid in the heat exchange flow, and improve the heat exchange effect of the heat exchanger.

Of course, in other embodiments, the number of spiral sectors 3 and the thickness d of the spiral sectors 3 may be varied according to the heat exchange requirements of different heat engines₁The normal width d of the fluid flow passage 4₂And the radial span d of the spiral sector 3₃Other suitable values can be taken, and the invention is not limited to the above limitation, as long as the heat exchanger structure with a plurality of spiral sectors 3 arranged at equal intervals in the circumferential direction and the radial direction is within the protection scope of the invention.

The internal structure of the heat exchanger on the side of the second end face 6 is shown in fig. 8-9. A guide plate 23 is arranged on one side of the inner shell 2 of the heat exchanger close to the second end surface 6, and the guide plate 23 is used for guiding hot fluid, so that the hot fluid enters the heat exchanger from a plurality of hot fluid inlets 22 on one side of the second end surface 6 and flows out from a hot fluid outlet 51 of the first end surface 5.

As shown in fig. 10 and 11, the present embodiment also provides a micro internal combustion engine 200, and the micro internal combustion engine 200 includes a compressor 201, a combustion chamber 202, and a turbine 203. Air is compressed by the compressor 201 and enters the combustion chamber 202, and is mixed with fuel and combusted in the combustion chamber 202, and the combusted high-temperature gas pushes the turbine 203 to rotate, so that flying equipment or other equipment provided with the micro combustion engine 200 is driven to move. The structure and principle of the micro combustion engine 200 are well known in the art and will not be described in detail herein. The micro combustion engine 200 further comprises the heat exchanger 100, the heat exchanger 100 is arranged around the outer side of the combustion chamber 202, air is compressed by the compressor 201 and exchanges heat with the heat exchanger 100 in sequence and then enters the combustion chamber 202, and high-temperature gas exhausted from the combustion chamber 202 pushes the turbine 203 to do work and is exhausted to the outside after exchanging heat with the heat exchanger 100. In the present embodiment, the heat exchanger 100 is fixed to the micro combustion engine 200 by bolts, and sealing devices are disposed between the first end surface 5 and the second end surface 6 of the heat exchanger 100 and the micro combustion engine 100.

The intake path of the micro internal combustion engine 200 is shown in fig. 12. The flow path of the intake air is as shown by arrow I, the external fresh air enters the micro combustion engine 200 through the intake port of the compressor 201, then diffuses outward in the radial direction of the micro combustion engine 200 and enters the heat exchanger 100, the fresh air flows spirally inward along the cold fluid flow channel 42 in the heat exchanger 100, flows out from the plurality of cold fluid outlets 21 arranged on the inner shell 2 of the heat exchanger 100, and finally enters the combustion chamber 201 through the plurality of hollowed intake ports arranged on the chamber wall of the combustion chamber 201.

The exhaust path of the micro internal combustion engine 200 is shown in fig. 13. The flow path of the exhaust gas is as shown by an arrow J, the high-temperature gas after combustion is discharged from the combustion chamber 202 toward one side opening of the turbine 203 and pushes the turbine 203 to rotate, the guide plate 23 of the heat exchanger 100 abuts against the side wall of the turbine chamber of the micro combustion engine 200 to form a guide space for guiding the high-temperature gas, and the high-temperature gas enters the plurality of hot fluid inlets 22 arranged on the inner housing 2 of the heat exchanger 100 after being guided by the guide space, spirally flows outwards in the plurality of hot fluid flow channels 41 in the heat exchanger 100, and finally flows out from the hot fluid outlet 51 on the second end surface 6 of the heat exchanger. The discharged high-temperature gas has a large momentum, which pushes the micro combustion engine 200 to move in a direction opposite to the exhaust direction, thereby driving the flying apparatus or other apparatuses in which the micro combustion engine 200 is installed to move.

Compared with the existing combustion engine equipment, the micro combustion engine 200 provided by the embodiment has the advantages of higher heat exchange efficiency, smaller volume, less emission of nitrogen oxides and higher power as a whole due to the adoption of the heat exchanger 100.

It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A heat exchanger, comprising: the spiral fluid flow channel comprises an outer shell (1), an inner shell (2) and a plurality of spiral sectors (3) enveloped between the outer shell (1) and the inner shell (2), wherein the outer ends of the spiral sectors (3) are connected to the outer shell (1), the other ends of the spiral sectors are spirally and inwardly connected to the inner shell (2) in a surrounding manner, and two adjacent spiral sectors (3) enclose a fluid flow channel (4) forming a spiral shape;

the fluid flow channels (4) on two sides of the spiral fan surface (3) are respectively a hot fluid flow channel (41) and a cold fluid flow channel (42), and the hot fluid flow channels (41) and the cold fluid flow channels (42) are distributed at intervals;

the hot fluid flow channel (41) is open towards one end of the first end face (5) of the heat exchanger (100), and the hot fluid flow channel (41) is closed towards one end of the second end face (6) of the heat exchanger (100);

the cold fluid flow channel (42) is closed towards one end of the first end face (5), and the cold fluid flow channel (42) is open towards one end of the second end face (6);

a plurality of cold fluid outlets (21) are arranged at equal intervals along the circumferential direction at one end of the inner shell (2) close to the first end surface (5), and the cold fluid outlets (21) are respectively communicated with the cold fluid runners (42);

one end, close to the second end face (6), of the inner shell (2) is provided with a plurality of hot fluid inlets (22) at equal intervals along the circumferential direction, and the plurality of hot fluid inlets (22) are respectively communicated with the plurality of hot fluid flow channels (41).

2. The heat exchanger according to claim 1, characterized in that a plurality of the spiral sectors (3) are evenly distributed in the circumferential direction of the heat exchanger (100), and a plurality of the spiral sectors (3) are arranged at equal intervals in the radial direction of the heat exchanger (100).

3. Heat exchanger according to claim 1, wherein the thickness d of the spiral sector (3)₁Between 0.25 and 1 mm.

4. The heat exchanger according to claim 1, characterized in that the number of spiral sectors (3) is between 20 and 30.

5. Heat exchanger according to claim 1, wherein the fluid flow channel (4) has a normal width d₂Is between 0.5 and 1 mm.

6. Heat exchanger according to claim 1, wherein the radial width between the outer casing (1) and the inner casing (2), i.e. the radial span d of the helical sector (3), is such that₃Between 20mm and 50 mm.

7. The heat exchanger according to claim 1, characterized in that the heat exchanger (100) is integrally machined by laser powder-laying additive manufacturing techniques.

8. A micro-combustion engine, characterized in that it comprises a heat exchanger (100) according to any one of claims 1 to 7, said heat exchanger (100) being housed outside a combustion chamber (202) of said micro-combustion engine (200) for heat exchange between cold and hot fluids entering and exiting said combustion chamber (202).