A combined multi-stage high-efficiency heat exchanger suitable for coaxial airflow

Abstract

The present invention provides a combined multi-stage high-efficiency heat exchanger suitable for coaxial airflow, belonging to the field of fluid heat exchange technology. The heat exchanger includes a multi-stage unit heat exchanger, an axial airflow inlet, an internal fixed ring, an external fixed ring and an axial airflow outlet. The heat exchanger described in the present invention is a composite heat exchanger that uses liquid metal as a heat transfer medium and uses microchannels for heat transfer; the heat exchange area of ​​the heat exchanger can be increased in a limited space. Compared with the traditional single-stage shell and tube heat exchanger, the effective heat exchange area per unit heat exchange space is increased by about 50%.

Description

Technical Field

[0001] The invention belongs to the technical field of fluid heat exchange, and in particular relates to a combined multi-stage high-efficiency heat exchanger suitable for coaxial airflow. Background Art

[0002] There are many types of existing heat exchangers, each with its own characteristics. According to the heat transfer principle, they can be divided into: partition heat exchangers, heat storage heat exchangers, fluid-connected indirect heat exchangers, direct contact heat exchangers, and compound heat exchangers, etc.; according to the structure, they can be divided into: floating head heat exchangers, fixed tube plate heat exchangers, U-shaped tube plate heat exchangers, and plate heat exchangers, etc. The shell and tube heat exchanger has a strong structure, is reliable, has strong adaptability, is easy to manufacture, and can withstand high pressure and temperature, but its heat transfer efficiency and compact structure are not as good as other new heat exchangers. The coil heat exchanger has a simple structure, low cost, and low operational sensitivity, but the flow rate of the fluid outside the tube is very small, so the heat transfer coefficient is small, the heat transfer efficiency is low, and the required heat transfer area is large. The shell and tube heat exchanger has a simple structure and a high heat transfer coefficient, but the metal consumption is large and the maintenance and cleaning are troublesome. The tube plate heat exchanger has a large heat transfer area, high heat transfer efficiency, and is easy to manufacture, but the flow resistance is large, the flow channel is easy to clog, and the pressure resistance is worse than the tube heat exchanger. The working temperatures of existing common heat exchangers vary greatly. The maximum temperature resistance of floating head heat exchangers is about 400℃ and the pressure resistance is about 6.4MPa; the working temperature of plate heat exchangers is -30℃~180℃ and the maximum pressure is about 1.6MPa; plate-fin heat exchangers can be used for heat exchange at a temperature of 1000K if appropriate materials are selected.

[0003] The disadvantages of the heat exchanger in the prior art are:

[0004] 1) The heat exchanger design is not designed for the high-temperature, high-pressure axial flow environment, and is not designed specifically for the target environment. Existing heat exchangers are usually designed for different application occasions, and it is difficult to take into account the requirements of multiple parameters such as working temperature, heat exchange medium, structural compactness, flow pressure drop, etc. In addition, under high temperature conditions, due to the limitations of the use space and material properties, the heat exchange area of ​​common heat exchangers is difficult to meet the heat exchange requirements, and special structural design is required to increase the compactness of the structure.

[0005] 2) Axial flow conditions have high requirements for heat exchange efficiency and axial flow loss of heat exchangers. The existing heat exchangers have high flow loss. On the one hand, the heat exchange process is required to pursue the best heat exchange efficiency and heat exchange speed. On the other hand, the heat exchange process of the heat exchanger is required to reduce the interference of the flow to the minimum stage to reduce the loss of axial flow. The existing heat exchange surface design of the heat exchanger causes large airflow loss, which affects the heat exchange efficiency of the airflow.

[0006] In view of the above problems, the present invention designs a heat exchanger to solve the problem of insufficient structural design of traditional heat exchangers, provide a high-efficiency, low-airflow loss heat exchange environment under high-pressure and high-temperature axial airflow environment, improve the heat exchange efficiency of the heat exchanger, and reduce the flow loss during the heat exchange process of the heated airflow. Summary of the invention

[0007] In order to achieve the above object, the present invention provides a heat exchanger with high heat exchange efficiency, compact structure and suitable for use in tube-type or ring-type channels. The heat exchanger is a composite heat exchanger that uses liquid metal as a heat transfer medium and uses microchannels for heat transfer.

[0008] The technical solution of the present invention is:

[0009] A combined multi-stage high-efficiency heat exchanger suitable for coaxial airflow comprises a unit heat exchanger 1-1, an axial airflow inlet 1-2, an inner fixing ring 1-3, an outer fixing ring 1-4 and an axial airflow outlet 1-5.

[0010] The unit heat exchanger 1-1 includes a heating medium inlet pipeline 2-1, a heating medium primary shunt pipe 2-2, a heating medium secondary shunt pipe 2-3, corrugated heat exchange thin fins 2-4, a heating medium secondary manifold 2-5, a heating medium primary manifold 2-6, a heating medium outlet pipeline 2-7, a heating inlet 2-8 and a heating outlet 2-9.

[0011] The corrugated heat exchange thin fins 2-4 are flat tube structures with openings at both ends. Both opening ends are uniformly corrugated, and the distribution interval between two adjacent corrugations is no more than 20 mm. The chamber between the two opening ends forms a wavy rectangular flow channel, and the upper and lower surfaces of the wavy rectangular flow channel are spaced no more than 10 mm. The opening ends of the 60 corrugated heat exchange thin fins 2-4 are evenly distributed along the axis, with a distribution angle interval of 6°, forming a cylindrical structure.

[0012] The first-level shunt pipe 2-2 for heating medium and the first-level collector pipe 2-6 for heating medium are respectively located at the two ends of the cylindrical structure; the first-level shunt pipe 2-2 for heating medium and the first-level collector pipe 2-6 for heating medium are both closed annular tubes, and the surfaces facing the cylindrical structure of the two are evenly and evenly provided with an equal number of through holes in the circumferential direction. The second-level shunt pipe 2-3 for heating medium and the second-level collector pipe 2-5 for heating medium are both tubular structures with the same length as the length of the open end of the corrugated heat exchange thin fin 2-4, and both are provided with openings in the length direction. The second-level shunt pipe 2-3 for heating medium and the second-level collector pipe 2-5 for heating medium are respectively connected to the open end of the corrugated heat exchange thin fin 2-4 located outside the cylindrical structure and the open end located inside the cylindrical structure through the openings. One end of the second-level shunt pipe 2-3 for heating medium and the second-level collector pipe 2-5 for heating medium are respectively connected to the through holes on the first-level shunt pipe 2-2 for heating medium and the first-level collector pipe 2-6 for heating medium.

[0013] The heating medium inlet pipeline 2-1 is connected to the heating medium primary flow divider 2-2, and the heating medium outlet pipeline 2-7 is connected to the heating medium primary flow collector 2-6. The channel between adjacent corrugated heat exchange thin fins 2-4 forms a heating flow channel for the target heating gas, and the two ends of the heating flow channel are respectively a heating inlet 2-8 and a heating outlet 2-9, wherein the heating inlet 2-8 is located at the end of the heating medium outlet pipeline 2-7, and the heating outlet 2-9 is located at the end of the heating medium inlet pipeline 2-1.

[0014] The inner fixing ring 1-3 is embedded in the center of the unit heat exchanger 1-1, and the outer fixing ring 1-4 is sleeved on the outer periphery of the unit heat exchanger 1-1. The central axes of the inner fixing ring 1-3, the outer fixing ring 1-4 and the corrugated heat exchange thin fins 2-4 are consistent.

[0015] The unit heat exchangers 1-1 are arranged in multiple stages along the axis direction; the corrugated heat exchange thin fins 2-4 of the adjacent two-stage unit heat exchangers are arranged in different directions around the central axis, that is, the corrugated heat exchange thin fins 2-4 in the first-stage unit heat exchanger are arranged in a counterclockwise direction, and the corrugated heat exchange thin fins 2-4 in the next-stage unit heat exchanger are arranged in a clockwise direction, and so on. The corrugated heat exchange thin fins 2-4 of the multi-stage unit heat exchangers are connected in series along the axis direction to form a heating flow channel for the target heating gas, and the two ends of the heating flow channel are the axis airflow inlet 1-2 and the axis airflow outlet 1-5 respectively.

[0016] Furthermore, the manufacturing materials of the heating working medium inlet pipeline 2-1, the heating working medium first-level shunt pipe 2-2, the heating working medium second-level shunt pipe 2-3, the corrugated heat exchange thin fins 2-4, the heating working medium second-level collector 2-5, the heating working medium first-level collector 2-6 and the heating working medium outlet pipeline 2-7 have high temperature resistance and good thermal conductivity, including alloy materials such as tantalum-tungsten alloy, nickel-tungsten alloy, titanium-tungsten alloy, nickel-tantalum alloy, niobium-tungsten alloy or niobium-tantalum alloy, and composite materials such as silicon carbide.

[0017] Furthermore, the high-temperature heat source working fluid is a liquid material with heat exchange capacity and high thermal conductivity under high temperature conditions, including liquid metal materials such as liquid lithium, liquid sodium, liquid potassium, liquid rubidium, liquid cesium, or liquid high-temperature alloy materials and liquid non-metallic materials.

[0018] The working process of the target heating gas in the unit heat exchanger is:

[0019] The high-temperature heat source fluid flows in from the heating fluid inlet pipe 2-1, and is distributed through the heating fluid primary shunt pipe 2-2 and the heating fluid secondary shunt pipe 2-3 in turn. The fluid flows from the heating fluid secondary shunt pipe 2-3 into the flow channel of the corrugated heat exchange thin fin 2-4, and is then collected by the heating fluid secondary manifold 2-5, and then enters the heating fluid primary manifold 2-6, and finally flows out from the heating fluid outlet pipe 2-7, realizing the cooling process of the high-temperature heat source fluid. The target heating gas flows in from the heating inlet 2-8, exchanges heat in the heating flow channel, and the heated fluid flows out from the heating outlet 2-9, realizing the heating process of the target heating gas in the heat exchanger.

[0020] The working process of the heat exchanger is:

[0021] The target heating gas enters the combined multi-stage high-efficiency heat exchanger through the axial airflow inlet 1-2, exchanges heat with the high-temperature heat source working fluid in the different-stage unit heat exchangers 1-1, and after being heated, the target heating gas flows out from the axial airflow outlet 1-5.

[0022] The reason why the arrangement directions of the corrugated heat exchange thin fins 2-4 between the multi-stage unit heat exchangers are opposite is that the airflow after passing through the unit heat exchanger will generate additional tangential flow due to the spiral pipeline formed by the corrugated heat exchange thin fins 2-4, and for the overall flow, a swirl around the axis will be formed, which aggravates the flow loss. The present invention effectively suppresses the generation of the above swirl and reduces the flow loss by setting the arrangement directions of the corrugated heat exchange thin fins 2-4 of different levels.

[0023] Beneficial effects of the invention: The invention proposes a new heat exchange method for axial high-speed and high-pressure airflow, and provides a combined multi-stage high-efficiency heat exchanger. The heat exchanger can increase the heat exchange area of ​​the heat exchanger in a limited space, and compared with the traditional single-stage shell and tube heat exchanger, the effective heat exchange area per unit heat exchange space is increased by about 50%. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the overall structure of the heat exchanger of the present invention.

[0025] Figure 2 It is a structural diagram of a unit heat exchanger.

[0026] Figure 3 It is a schematic diagram of the arrangement of different levels of corrugated heat exchange thin fins.

[0027] Figure 4 It is a schematic diagram of the structure of the corrugated heat exchange thin fin.

[0028] In the figure: 1-1 unit heat exchanger; 1-2 axis air flow inlet; 1-3 internal fixed ring; 1-4 external fixed ring; 1-5 axis air flow outlet; 2-1 heating medium inlet pipeline; 2-2 heating medium first-stage shunt pipe; 2-3 heating medium second-stage shunt pipe; 2-4 corrugated heat exchange thin fins; 2-5 heating medium second-stage manifold; 2-6 heating medium first-stage manifold; 2-7 heating medium outlet pipeline; 2-8 heating inlet; 2-9 heating outlet; 3-1 odd-numbered corrugated heat exchange thin fins; 3-2 even-numbered corrugated heat exchange thin fins. DETAILED DESCRIPTION

[0029] The present invention is further described below in conjunction with embodiments and drawings.

[0030] like Figure 1 As shown, a combined multi-stage high-efficiency heat exchanger suitable for coaxial airflow includes a unit heat exchanger 1-1, an axial airflow inlet 1-2, an inner fixing ring 1-3, an outer fixing ring 1-4 and an axial airflow outlet 1-5.

[0031] like Figure 2 As shown, the unit heat exchanger 1-1 includes a heating medium inlet pipeline 2-1, a heating medium primary branch pipe 2-2, a heating medium secondary branch pipe 2-3, a corrugated heat exchange thin fin 2-4, a heating medium secondary manifold 2-5, a heating medium primary manifold 2-6, a heating medium outlet pipeline 2-7, a heating inlet 2-8 and a heating outlet 2-9.

[0032] like Figure 4 As shown, the corrugated heat exchange thin fin 2-4 is a flat tube structure with two openings at both ends. Both opening ends are uniformly corrugated, and the distribution interval between two adjacent corrugations is 20mm. The chamber between the two opening ends forms a wavy rectangular flow channel, and the interval between the upper and lower surfaces of the wavy rectangular flow channel is 10mm. The opening ends of 60 corrugated heat exchange thin fins 2-4 are distributed circumferentially along the axis, with a distribution angle interval of 6°, forming a cylindrical structure.

[0033] The heating medium primary shunt pipe 2-2 and the heating medium primary manifold pipe 2-6 are respectively located at the two ends of the cylindrical structure; the heating medium primary shunt pipe 2-2 and the heating medium primary manifold pipe 2-6 are both closed annular tubes, and 60 through holes are evenly spaced along the circumferential direction on the surfaces facing the cylindrical structure. The heating medium secondary shunt pipe 2-3 and the heating medium secondary manifold pipe 2-5 are both tubular structures with the same length as the length of the open end of the corrugated heat exchange thin fin 2-4, and both are provided with openings in the length direction. The heating medium secondary shunt pipe 2-3 and the heating medium secondary manifold pipe 2-5 are respectively connected to the open end of the corrugated heat exchange thin fin 2-4 located outside the cylindrical structure and the open end located inside the cylindrical structure through the openings. One end of the heating medium secondary shunt pipe 2-3 and the heating medium secondary manifold pipe 2-5 are respectively connected to the through holes on the heating medium primary shunt pipe 2-2 and the heating medium primary manifold pipe 2-6.

[0034] The heating medium inlet pipeline 2-1 is connected to the heating medium primary flow divider 2-2, and the heating medium outlet pipeline 2-7 is connected to the heating medium primary flow collector 2-6. The channel between adjacent corrugated heat exchange thin fins 2-4 forms a heating flow channel for the target heating gas, and the two ends of the heating flow channel are respectively a heating inlet 2-8 and a heating outlet 2-9, wherein the heating inlet 2-8 is located at the end of the heating medium outlet pipeline 2-7, and the heating outlet 2-9 is located at the end of the heating medium inlet pipeline 2-1.

[0035] The inner fixing ring 1-3 is embedded in the center of the unit heat exchanger 1-1, and the outer fixing ring 1-4 is sleeved on the outer periphery of the unit heat exchanger 1-1. The central axes of the inner fixing ring 1-3, the outer fixing ring 1-4 and the corrugated heat exchange thin fins 2-4 are consistent.

[0036] The unit heat exchanger 1-1 is arranged in multiple stages along the axis direction, and the arrangement is as follows: along the flow direction, there are first-stage unit heat exchangers, second-stage unit heat exchangers, and so on; the corrugated heat exchange thin fins 2-4 of the adjacent two-stage unit heat exchangers are arranged in different directions around the central axis, that is, the corrugated heat exchange thin fins 2-4 in the first-stage unit heat exchanger are arranged in a counterclockwise direction, and the corrugated heat exchange thin fins 2-4 in the second-stage unit heat exchanger are arranged in a clockwise direction, and so on. The corrugated heat exchange thin fins 2-4 of the multi-stage unit heat exchanger 1-1 are connected in series along the axis direction to form a heating flow channel for the target heating gas, and the two ends of the heating flow channel are respectively the axis airflow inlet 1-2 and the axis airflow outlet 1-5.

[0037] The high-pressure and high-speed airflow enters the heat exchanger combination through the axial airflow inlet 1-2, exchanges heat with the high-temperature heat source working fluid in the unit heat exchangers 1-1 at different levels, and the target heating gas is heated and flows out from the axial airflow outlet 1-5.

[0038] The working process of high-pressure and high-speed airflow in the unit heat exchanger is:

[0039] The high-temperature heat source fluid flows in from the heating fluid inlet pipe 2-1, and then the flow is distributed by the heating fluid primary shunt pipe 2-2 connected to the heating fluid inlet pipe 1, and the heating fluid secondary shunt pipe 2-3 is connected to the through hole of the heating fluid primary shunt pipe 2-2 by welding; the fluid flows from the heating fluid secondary shunt pipe 2-3 into the chamber flow channel in the corrugated heat exchange thin fin 2-4, and then is collected by the heating fluid secondary manifold 2-5, and then enters the heating fluid primary manifold 2-6, and finally flows out from the heating fluid outlet pipe 2-7, realizing the cooling process of the high-temperature heat source fluid. The high-pressure and high-speed airflow flows in from the heating inlet 2-8, exchanges heat in the heating flow channel, and the heated fluid flows out from the heating outlet 2-9, realizing the heating process of the target heating gas in the heat exchanger.

Claims

1. A combined multi-stage high-efficiency heat exchanger suitable for coaxial airflow, characterized in that: The heat exchanger comprises a unit heat exchanger (1-1), an axial airflow inlet (1-2), an inner fixing ring (1-3), an outer fixing ring (1-4) and an axial airflow outlet (1-5); The unit heat exchanger (1-1) comprises a heating medium inlet pipeline (2-1), a heating medium primary flow divider (2-2), a heating medium secondary flow divider (2-3), corrugated heat exchange thin fins (2-4), a heating medium secondary flow collector (2-5), a heating medium primary flow collector (2-6) and a heating medium outlet pipeline (2-7); The corrugated heat exchange thin fin (2-4) is a flat tube structure with two openings at both ends, both openings are uniformly corrugated, and the distribution interval between two adjacent corrugations is no more than 20 mm; the chamber between the two openings forms a corrugated rectangular flow channel, and the interval between the upper and lower surfaces of the corrugated rectangular flow channel is no more than 10 mm; the openings of 60 corrugated heat exchange thin fins (2-4) are uniformly distributed along the circumference of the axis, and the distribution angle interval is 6°, forming a cylindrical structure; The first-stage shunt pipe (2-2) for heating working medium and the first-stage merging pipe (2-6) for heating working medium are respectively located at the two ends of the cylindrical structure; the first-stage shunt pipe (2-2) for heating working medium and the first-stage merging pipe (2-6) for heating working medium are both closed annular tubes, and the surfaces facing the cylindrical structure of the two are evenly provided with an equal number of through holes at equal intervals in the circumferential direction; the second-stage shunt pipe (2-3) for heating working medium and the second-stage merging pipe (2-5) for heating working medium are both the same length as the length of the opening end of the corrugated heat exchange thin fin (2-4). The two heating medium second flow divider (2-3) and the heating medium second flow collector (2-5) are respectively connected to the opening end of the corrugated heat exchange thin fin (2-4) located outside the cylindrical structure and the opening end located inside the cylindrical structure through the openings; one end of the heating medium second flow divider (2-3) and the heating medium second flow collector (2-5) are respectively connected to the through holes on the heating medium first flow divider (2-2) and the heating medium first flow collector (2-6); The heating medium inlet pipeline (2-1) is connected to the heating medium primary flow divider (2-2), and the heating medium outlet pipeline (2-7) is connected to the heating medium primary flow collector (2-6); the channel between adjacent corrugated heat exchange thin fins (2-4) forms a heating flow channel for the target heating gas, and the two ends of the heating flow channel are respectively a heating inlet (2-8) and a heating outlet (2-9), wherein the heating inlet (2-8) is located at the end of the heating medium outlet pipeline (2-7), and the heating outlet (2-9) is located at the end of the heating medium inlet pipeline (2-1); The inner fixing ring (1-3) is embedded in the center of the unit heat exchanger (1-1), and the outer fixing ring (1-4) is sleeved on the outer periphery of the unit heat exchanger (1-1); the central axes of the inner fixing ring (1-3), the outer fixing ring (1-4) and the corrugated heat exchange thin fins (2-4) are consistent; The unit heat exchangers (1-1) are arranged in multiple stages along the axial direction, and the corrugated heat exchange thin fins (2-4) of two adjacent unit heat exchangers are arranged in opposite directions of rotation around the central axis; the corrugated heat exchange thin fins (2-4) of the multi-stage unit heat exchangers are connected in series along the axial direction to form a heating flow channel for the target heating gas, and the two ends of the heating flow channel are respectively an axial airflow inlet (1-2) and an axial airflow outlet (1-5).

2. A combined multi-stage high-efficiency heat exchanger suitable for coaxial airflow according to claim 1, characterized in that: The manufacturing materials of the heating medium inlet pipeline (2-1), the heating medium primary shunt pipe (2-2), the heating medium secondary shunt pipe (2-3), the corrugated heat exchange thin fins (2-4), the heating medium secondary manifold (2-5), the heating medium primary manifold (2-6) and the heating medium outlet pipeline (2-7) include tantalum-tungsten alloy, nickel-tungsten alloy, titanium-tungsten alloy, nickel-tantalum alloy, niobium-tungsten alloy, niobium-tantalum alloy or silicon carbide.

3. A combined multi-stage high-efficiency heat exchanger suitable for coaxial airflow according to claim 1 or 2, characterized in that: The heating medium includes liquid metal material, liquid alloy material or liquid non-metal material.

4. A combined multi-stage high-efficiency heat exchanger suitable for coaxial airflow according to claim 3, characterized in that: The liquid metal material includes liquid lithium, liquid sodium, liquid potassium, liquid rubidium or liquid cesium.

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