Tube bundle heat exchanger, method for calibrating heat exchange performance thereof and thermoacoustic heat engine

Abstract

The present application relates to heat exchange equipment technical field, provide a kind of tube bundle heat exchanger and its heat exchange performance calibration method and thermoacoustic heat engine.Tube bundle heat exchanger includes shell, heating part and tube bundle, shell includes heat exchange cavity and working cavity, heat exchange cavity is spaced apart with working cavity, liquid metal is provided in heat exchange cavity;Heating part is worn in heat exchange cavity, for heating liquid metal;Tube bundle is worn in heat exchange cavity, and is spaced apart with heating part, the opening of both ends of tube bundle is communicated with working cavity, and tube bundle is used for transmitting working gas.The tube bundle heat exchanger provided by the present application forms a uniform temperature field by the combination of heating part and liquid metal, the power of heating part can be directly used as the reference data of tube bundle heat exchanger heat exchange performance measurement, there is no high-temperature flame and high-temperature flue gas and other heat source in the heat exchange process of tube bundle heat exchanger, i.e.there is no complex radiation and convection heat transfer mode, effectively reduce the difficulty of heat exchanger performance accurate evaluation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of heat exchange equipment, in particular to a tube bundle heat exchanger and a heat exchange performance calibration method thereof and a thermoacoustic heat engine. BACKGROUND

[0002] The thermoacoustic heat engine is a device that converts heat energy directly into acoustic energy or mechanical energy by using the thermoacoustic effect, and the conversion process is based on the generation of sound waves by the gas under the action of a periodic temperature gradient. The high-temperature heat exchanger, as the heat input end of the thermoacoustic heat engine, faces the challenges of high heat flux density and complex working environment, and its design is crucial to the thermal efficiency and stability of the entire system. The tube bundle heat exchanger is the most commonly used high-temperature heat exchanger in the thermoacoustic heat engine, and in the thermoacoustic heat engine driven by fuel, the tube bundle heat exchanger mainly realizes heat transfer through its internal tube bundle structure.

[0003] The tube bundle heat exchanger generally adopts a direct combination with the burner, that is, the high-temperature flame and high-temperature flue gas generated by the burner directly act on the tube bundle of the tube bundle heat exchanger. However, the complex radiation and convection heat transfer mode of the high-temperature flame and high-temperature flue gas brings great difficulty to the accurate evaluation of the performance of the heat exchanger. SUMMARY

[0004] The first aspect of the present application provides a tube bundle heat exchanger to solve the defects of the direct combination of the tube bundle heat exchanger with the burner in the prior art. A uniform temperature field is formed by the combination of the heating element and the liquid metal. The power of the heating element can be directly used as reference data for measuring the heat exchange performance of the tube bundle heat exchanger. In the heat exchange process of the tube bundle heat exchanger, there is no participation of heat sources such as high-temperature flame and high-temperature flue gas, that is, there is no complex radiation and convection heat transfer mode, which effectively reduces the difficulty of accurate evaluation of the performance of the heat exchanger.

[0005] The second aspect of the present application provides a thermoacoustic heat engine.

[0006] The third aspect of the present application provides a heat exchange performance calibration method of a tube bundle heat exchanger.

[0007] The tube bundle heat exchanger provided by the present application comprises:

[0008] The shell comprises a heat exchange cavity and a working cavity, the heat exchange cavity and the working cavity are arranged at intervals, and the liquid metal is arranged in the heat exchange cavity;

[0009] The heating element is arranged in the heat exchange cavity and used for heating the liquid metal;

[0010] The tube bundle is arranged in the heat exchange cavity and arranged at intervals with the heating element. The openings at both ends of the tube bundle are communicated with the working cavity, and the tube bundle is used for transmitting the working gas.

[0011] According to the pipe bundle heat exchanger provided by the application, the heating elements are arranged in multiple, the multiple heating elements are arranged in the heat exchange cavity at intervals, and each heating element can be independently controlled.

[0012] According to the pipe bundle heat exchanger provided by the application, the extending direction of the heating elements is perpendicular to the axis of the heat exchange cavity, and the multiple heating elements are arranged at intervals along the axis of the heat exchange cavity.

[0013] According to the pipe bundle heat exchanger provided by the application, the working cavity comprises an expansion cavity and a regenerative cavity, the heat exchange cavity is arranged around the expansion cavity, and a support is arranged between the cavity wall of the expansion cavity and the cavity wall of the heat exchange cavity;

[0014] The regenerative cavity is arranged on the side of the expansion cavity away from the support, the opening of one end of the pipe bundle is in communication with the regenerative cavity, and the opening of the other end of the pipe bundle is in communication with the expansion cavity.

[0015] According to the pipe bundle heat exchanger provided by the application, the extending direction of the heating elements is parallel to the axis of the heat exchange cavity, and the multiple heating elements are arranged at intervals around the axis of the heat exchange cavity.

[0016] The heat engine provided by the application comprises the pipe bundle heat exchanger according to any one of the preceding.

[0017] According to the heat engine provided by the application, the pipe bundle heat exchanger is arranged in two, and the two pipe bundle heat exchangers are arranged oppositely.

[0018] The two heat exchange cavities are in communication with each other, and the two working cavities are in communication with each other.

[0019] The heat engine provided by the application further comprises a heat pipe, one end of the heat pipe is used for being connected with a remote heat source, the other end of the heat pipe is connected with the heat exchange cavity of the pipe bundle heat exchanger, and the heat pipe is used for transmitting heat.

[0020] The method for calibrating the heat exchange performance of the pipe bundle heat exchanger provided by the application comprises

[0021] The initial power of the heating element and the flow of the working gas are set;

[0022] According to a preset target, one or more heating elements are selected, the power of each heating element is adjusted one by one, and the heat exchange data of the working gas is collected;

[0023] The heat exchange efficiency of the pipe bundle heat exchanger is calculated according to the heat exchange data.

[0024] The method for calibrating the heat exchange performance of the pipe bundle heat exchanger provided by the application further comprises the following step after the step of calculating the heat exchange efficiency of the pipe bundle heat exchanger according to the heat exchange data:

[0025] The power distribution of each heating element is adjusted through a feedback mechanism to determine the optimal heat exchange performance of the tube bundle heat exchanger under different working conditions.

[0026] The tube bundle heat exchanger provided by the application can be used for calibration, and working gas in the working cavity can enter the heat exchange cavity through the tube bundle.

[0027] Secondly, since the liquid metal has large heat capacity and high thermal conductivity and can flow freely in the heat exchange cavity, the liquid metal can rapidly absorb a large amount of heat and store it when the heating element heats the liquid metal, forming a stable and uniform temperature field.

[0028] In addition, due to the negative temperature expansion characteristic of the liquid metal, the volume of the liquid metal does not expand but gradually decreases with the increase of temperature during the heating process of the heating element.

[0029] Compared with the form of directly combining the heat exchanger with the burner in the prior art, in the tube bundle heat exchanger provided by the embodiment of the application, a uniform temperature field is formed by the combination of the heating element and the liquid metal.

[0030] Secondly, in order to ensure the pressure bearing of the tube bundle, the tube bundle in the prior art is generally made of stainless steel, and the wall thickness of the tube bundle is generally made thin in consideration of the heat conduction problem, which results in that the tube bundle is very fast in response to the flame heat source, when the tube bundle heat exchanger is used in the thermoacoustic heat engine, this can cause great difficulty in the control of the moving parts, and due to the fast response of the tube bundle to the heat source, the temperature of the tube bundle can also change frequently, thereby aggravating the creep failure problem of the tube bundle material; in the embodiment of the present application, the heating element does not directly contact the tube bundle due to the presence of the liquid metal, and the uniform temperature field formed by the liquid metal and the heating element can slow down the response of the tube bundle and the internal working gas temperature to the heat source, so that, on the one hand, when the tube bundle heat exchanger is used in the thermoacoustic heat engine, a smooth transition can be provided for the stroke control of the moving parts, that is, the difficulty in forming the control of the moving parts can be effectively reduced; on the other hand, the thermal stress borne by the tube bundle material can be reduced, the creep failure of the tube bundle material can be slowed down, and thus the sealing performance and overall performance of the tube bundle heat exchanger can be effectively improved. In addition, the liquid metal and the tube bundle are combined in a close manner through the fluid domain and the solid domain, so that the tube bundle has no obvious constraint in the pressure bearing direction, the stress borne by the tube bundle can be reduced, and the safety of the tube bundle can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative labor.

[0032] Figure 1 is a cross-sectional structure schematic diagram of the tube bundle heat exchanger provided by the embodiment of the present application in one angle.

[0033] Figure 2 is a cross-sectional structure schematic diagram of the tube bundle heat exchanger provided by the embodiment of the present application in another angle.

[0034] Figure 3 is a layout schematic diagram of another structure of the heating element provided by the embodiment of the present application.

[0035] Figure 4 is a cross-sectional structure schematic diagram of the thermoacoustic heat engine provided by the embodiment of the present application.

[0036] Figure 5 is a half cross-sectional schematic diagram of the two tube bundle heat exchangers provided by the embodiment of the present application.

[0037] Figure 6 is a full cross-sectional schematic diagram of the two tube bundle heat exchangers provided by the embodiment of the present application.

[0038] Figure 7 Figure 1 is a flowchart of a heat exchange performance calibration method of a tube bundle heat exchanger according to an embodiment of the present application.

[0039] Reference signs:

[0040] 10: piston engine; 11: ejector; 12: regenerator; 13: room temperature heat exchanger; 20: linear motor; 30: tube bundle heat exchanger; 31: shell; 311: heat exchange cavity; 312: working cavity; 3121: expansion cavity; 3122: regenerator cavity; 32: heating element; 33: tube bundle; 34: support element. DETAILED DESCRIPTION

[0041] In order to make the objectives, technical solutions and advantages of the present application clearer, the technical solutions in the present application will be described clearly and completely below with reference to the drawings in the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of the present application.

[0042] In the description of the embodiments of the present application, it should be noted that unless specifically defined and limited, the terms "connected", "connected" should be understood broadly, for example, can be fixedly connected, can be detachably connected, or integrally connected; can be mechanically connected, or electrically connected; can be directly connected, or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0043] In the embodiments of the present application, unless specifically defined and limited, the first feature is "on" or "under" the second feature, which can be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature "above", "over" and "on" the second feature can be that the first feature is directly above or obliquely above the second feature, or only means that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "under" and "under" the second feature can be that the first feature is directly below or obliquely below the second feature, or only means that the horizontal height of the first feature is less than that of the second feature.

[0044] In the description of the specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the embodiments of the present application. In the specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the specification and the features of the different embodiments or examples without contradiction.

[0045] The tube bundle heat exchanger is generally directly combined with the burner, that is, the high-temperature flame and high-temperature flue gas generated by the burner directly act on the tube bundle heat exchanger. However, the complex radiation and convection heat transfer mode of the high-temperature flame and high-temperature flue gas brings great difficulty to the accurate evaluation of the performance of the heat exchanger. On the other hand, the low heat capacity of the tube bundle heat exchanger makes the internal working gas temperature extremely susceptible to the influence of the heat source, which brings difficulty to the stroke control of the moving parts; in addition, the temperature response characteristics of the tube bundle material will cause the tube bundle material to bear extremely high thermal stress, aggravate the creep failure of the heat exchanger material, and further affect the sealing performance and overall performance of the heat exchanger. In addition, the tube bundle heat exchanger naturally exists the effect that the temperature of the radiation surface is high and the temperature of the back radiation surface is low, which causes the working gas in the pipe to be unable to be uniformly heated, affecting the heat exchange effect.

[0046] Figure 1 is a cross-sectional structure schematic diagram of the tube bundle heat exchanger provided by the embodiment of the present application in one angle.

[0047] Referring to Figure 1 , the first aspect of the embodiment of the present application provides a tube bundle heat exchanger 30 for solving at least one of the above technical problems; the tube bundle heat exchanger 30 comprises a shell 31, a heating element 32 and a tube bundle 33, the shell 31 is a hollow structure, the hollow structure comprises a heat exchange cavity 311 and a working cavity 312, the heat exchange cavity 311 and the working cavity 312 are arranged in a spaced manner and are not communicated with each other, a large amount of liquid metal is filled in the heat exchange cavity 311, the liquid metal can flow freely in the heat exchange cavity 311, and the specific content of the liquid metal can be adaptively selected according to the actual situation.

[0048] The heating element 32 is arranged in the heat exchange cavity 311, the heating element 32 is directly contacted with the liquid metal and is completely wrapped by the liquid metal, and the heating element 32 is used for heating the liquid metal; the heating element 32 can be selected from existing heating devices such as heating fins or heating pipes; the tube bundle 33 is arranged in the heat exchange cavity 311 and is arranged in a spaced manner with the heating element 32, and is also completely wrapped by the liquid metal, the openings at both ends of the tube bundle 33 are communicated with the working cavity 312, and the tube bundle 33 is used for transmitting working gas.

[0049] Referring to Figure 1 It can be understood that the tube bundle heat exchanger 30 provided by the present application can be used for calibration, and the working gas in the working cavity 312 can enter the heat exchange cavity 311 through the tube bundle 33. When the heating element 32 heats the liquid metal, the liquid metal and the working gas can exchange heat through the wall surface of the tube bundle 33. By accurately controlling the power of the heating element 32 and collecting the temperature, pressure and flow data of the working gas in the tube bundle 33 and outside the tube bundle 33 in real time, the heat exchange efficiency of the tube bundle heat exchanger 30 can be directly and accurately measured, so that the calibration of the performance of the heat exchanger can be realized.

[0050] Secondly, since the liquid metal has large heat capacity and high thermal conductivity, and can flow freely in the heat exchange cavity 311, when the heating element 32 heats the liquid metal, the liquid metal can quickly absorb a large amount of heat and store it, forming a stable and uniform temperature field. Since the liquid metal is wrapped around the tube bundle 33 in all directions, the uniform temperature field can quickly and uniformly distribute heat to the tube bundle 33 at each position in the heat exchange cavity 311. On the one hand, this can ensure that the working gas in the tube bundle 33 is uniformly heated at different positions. This uniform heat exchange characteristic can make the temperature, pressure and flow of the working gas in the heat exchanger more consistent, reducing the data deviation caused by uneven local heat exchange. On the other hand, it can improve the consistency of the temperature of each point on the surface of the tube bundle 33, and can avoid the phenomenon of thermal stress concentration caused by local overheating or overcooling, greatly reducing the risk of damage to the structure of the tube bundle 33 caused by uneven temperature.

[0051] In addition, due to the negative temperature expansion characteristic of the liquid metal, the volume of the liquid metal will not expand, but will gradually decrease as the temperature rises during the heating process of the heating element 32. This can effectively reduce the stress of the liquid metal on the wall of the heat exchange cavity 311, thereby improving the overall safety of the tube bundle heat exchanger 30.

[0052] Compared with the form of directly combining the heat exchanger with the burner in the prior art, in the tube bundle heat exchanger 30 provided by the embodiment of the present application, a uniform temperature field is formed by the combination of the heating element 32 and the liquid metal. The power of the heating element 32 can be directly used as reference data for measuring the heat exchange performance of the tube bundle heat exchanger 30. In the heat exchange process of the tube bundle heat exchanger 30, there is no participation of heat sources such as high-temperature flame and high-temperature flue gas. That is, there is no complex radiation and convection heat exchange mode in the heat exchange process, and there is no effect of high radiation surface temperature and low back radiation surface temperature. This effectively reduces the difficulty of accurate evaluation of the performance of the heat exchanger.

[0053] Secondly, in order to ensure the pressure bearing property of the tube bundle 33, the tube bundle 33 in the prior art is generally made of stainless steel, and the wall thickness of the tube bundle 33 is generally made thin in consideration of the heat conduction problem, which results in that the tube bundle 33 has a very fast response to the heat source, and when the tube bundle heat exchanger 30 is used in the thermoacoustic heat engine, this will cause great difficulty in the control of the moving parts, and at the same time, due to the fast response of the tube bundle 33 to the heat source, the temperature of the tube bundle 33 will change frequently, which will further aggravate the creep failure problem of the tube bundle 33 material; in the embodiment of the present application, the heating element 32 does not directly contact the tube bundle 33 due to the presence of the liquid metal, and the uniform temperature field formed by the liquid metal and the heating element 32 can slow down the response of the tube bundle 33 and the internal working gas temperature to the heat source, so that on the one hand, when the tube bundle heat exchanger 30 is used in the thermoacoustic heat engine, a smooth transition can be provided for the stroke control of the moving parts, that is, the difficulty in forming the control of the moving parts can be effectively reduced; on the other hand, the thermal stress borne by the tube bundle 33 material can be reduced, the creep failure of the tube bundle 33 material can be slowed down, and thus the sealing property and overall performance of the tube bundle heat exchanger 30 can be effectively improved. In addition, the liquid metal and the tube bundle 33 are combined in a close manner through the fluid domain and the solid domain, so that the tube bundle 33 has no obvious constraint in the pressure bearing direction, the stress borne by the tube bundle 33 can be reduced, and the safety of the tube bundle 33 can be improved.

[0054] In the optional embodiment of the present application, the liquid metal can be selected from sodium-potassium alloy, gallium-indium-tin, molybdenum alloy, tungsten alloy, bismuth and alloys thereof, and the like. It can be understood that, compared with the conventional heat conduction medium, the liquid metal has a larger heat capacity and a higher upper limit of temperature that can be borne, so that heat storage can be effectively performed.

[0055] Figure 2 is a cross-sectional view of the tube bundle heat exchanger in another angle according to the embodiment of the present application.

[0056] Referring to Figure 1 and Figure 2 In the optional embodiment of the present application, the heating element 32 is provided in a plurality, the plurality of heating elements 32 are arranged at intervals in the heat exchange cavity 311, and each heating element 32 can be independently controlled. It can be understood that, different heating elements 32 are distributed at different positions, different heating powers can be provided for the heating elements 32 according to the positions of the heating elements 32, the heating power is increased in the area where more heat is needed, and the power is reduced in the area where less heat is needed, so that the heat distribution in the whole heat exchange cavity 311 can be more reasonable, and the uniformity of the whole temperature field can be ensured.

[0057] In addition, in practical applications, the heat output of the combustion heat source has complexity, and the heat flow size, temperature distribution and heat transfer mode thereof change with the change of the combustion process, for example, the fuel type, combustion intensity and burner structure all affect the combustion heat transfer, and the traditional calibration method usually calibrates through preset fixed temperature difference, flow and other conditions to obtain a group of data, which is difficult to accurately reproduce the complex heat input condition, resulting in a large deviation between the calibration result and the actual operation performance.

[0058] In the embodiment of the application, by controlling the power of the single or multiple heating elements 32, the dynamic heat load change caused by the actual combustion phenomena such as the change of the strength of the combustion flame and the movement of the combustion area can be simulated, and the heat input change at different moments and different areas in the combustion process can be accurately simulated. The flexible adjustment mode enables the tube bundle heat exchanger 30 to experience a similar heat load change process as the actual combustion heat transfer during the calibration process, thereby providing a basis for accurately measuring the heat transfer performance.

[0059] Secondly, in the combustion process, the heat is unevenly distributed around the burner, and by reasonably controlling the power of the heating elements 32 at different positions, a similar uneven heat distribution can be formed in the heat exchange cavity 311, which enables the liquid metal and the tube bundle 33 in the heat exchanger to work in a similar temperature field as the actual combustion heat transfer, thereby more accurately reflecting the heat transfer performance thereof under the actual combustion heat source.

[0060] In addition, through the power of the single or multiple heating elements 32, various working conditions that the heat exchanger may encounter in actual operation can be covered, whether it is start-up, stable operation or load change, and the like, and the corresponding heat input change can be simulated by adjusting the power of the heating elements 32. The extensive working condition simulation capability enables the heat transfer performance of the tube bundle heat exchanger 30 to be accurately measured under various actual working conditions, thereby improving the practicality and representativeness of the heat transfer performance calibration measurement result.

[0061] Meanwhile, the method is not only suitable for simulating the combustion heat source, but also can adapt to other types of heat sources by adjusting the power of the heating elements 32, for example, for a nuclear heat device and the like, although the heat output characteristics thereof are different from those of the combustion heat source, but by reasonably setting the power and working mode of the heating elements 32, the heat input condition of the tube bundle heat exchanger 30 can still be simulated. The adaptability to multiple heat sources enables the heat transfer performance of the tube bundle heat exchanger 30 to be accurately evaluated under different energy application scenarios, thereby widening the application range of the tube bundle heat exchanger 30 and the comprehensiveness of the performance evaluation.

[0062] In addition, since the heating element 32 does not need to be fixed with the tube bundle 33, the freedom of the layout of the tube bundle 33 can be improved, the heat exchange performance can be improved, and the compactness of the tube bundle heat exchanger 30 can be improved, thereby meeting the requirement of the thermoacoustic heat engine on the space utilization.

[0063] Referring back to Figure 1 In optional embodiments of the present application, the working cavity 312 includes an expansion cavity 3121 and a regenerative cavity 3122, the heat exchange cavity 311 is arranged around the expansion cavity 3121, and a support 34 is arranged between the cavity wall of the expansion cavity 3121 and the cavity wall of the heat exchange cavity 311.

[0064] The regenerative cavity 3122 is arranged on the side of the expansion cavity 3121 away from the support 34, and the regenerative cavity 3122 can be arranged in communication with the expansion cavity 3121, as shown in Figure 1 The regenerative cavity 3122 can also be arranged separately from the expansion cavity 3121, the diameter of the regenerative cavity 3122 is greater than the diameter of the expansion cavity 3121, the regenerative cavity 3122 is used to fill the regenerator 12, and the expansion cavity 3121 is used to discharge the piston 11 to perform piston movement, that is, to make the working gas work; one end of the tube bundle 33 is in communication with the regenerative cavity 3122, and the other end of the tube bundle 33 is in communication with the expansion cavity 3121, and the working gas can be transmitted in the regenerative cavity 3122 and the expansion cavity 3121 through the tube bundle 33.

[0065] It can be understood that, in the embodiments of the present application, when the piston 11 performs piston movement, the cavity wall of the expansion cavity 3121 will bear a large axial load due to the compression movement of the working gas, and the support 34 provided in the embodiments can play a supporting role to effectively resist this axial load, thereby ensuring the stability of the expansion cavity 3121.

[0066] Referring back to Figure 1 In optional embodiments of the present application, the extension direction of the heating element 32 is arranged perpendicularly to the axis of the heat exchange cavity 311, and a plurality of heating elements 32 are arranged uniformly along the axis of the heat exchange cavity 311, that is, the heating elements 32 are arranged transversely in the heat exchange cavity 311 along the side wall of the heat exchange cavity 311 and extend along the radial direction of the heat exchange cavity 311; it can be understood that, in this way, the heating elements 32 can be disassembled and assembled conveniently, and a uniform temperature field can be formed in the heat exchange cavity 311, thereby ensuring uniform heating of the tube bundle 33.

[0067] Figure 3 is a layout diagram of another structure of the heating element provided in the embodiments of the present application.

[0068] Referring back to Figure 3In the alternative embodiment of the present application, the extension direction of the heating element 32 is parallel to the axial direction of the heat exchange cavity 311, and the plurality of heating elements 32 are arranged at intervals around the axis of the heat exchange cavity 311. In another aspect, the plurality of heating elements 32 are inserted into the heat exchange cavity 311 along the bottom wall of the heat exchange cavity 311 and extend in the direction parallel to the axis of the heat exchange cavity 311, that is, the heating elements 32 are arranged longitudinally.

[0069] It can be understood that, since the heat exchange cavity 311 is arranged outside the expansion cavity 3121, the two will limit an annular cavity. When the liquid metal flows, the annular cavity will limit the flow, so that the liquid metal will circulate in the annular cavity. In the embodiment of the present application, the heating elements 32 are arranged longitudinally. When the liquid metal flows through the heating elements 32 perpendicular to the flow direction, the metal flow will encounter resistance or change direction on the surface of each heating element 32. This will make the liquid metal flow change direction near the heating elements 32, and the turning will promote the mixing of different parts of the liquid metal flow, thereby causing a mixing effect. In addition, turbulence or vortex may occur each time the heating element 32 passes through a heating element 32. Such flow changes intensify the exchange of substances or heat distribution in different regions of the liquid metal, which can make the flow more uniform.

[0070] Figure 4 is a cross-sectional structure schematic diagram of a thermoacoustic heat engine provided by the embodiment of the present application.

[0071] Referring to Figure 4 The second aspect of the embodiment of the present application provides a thermoacoustic heat engine, which comprises a piston engine 10, a linear motor 20, and the tube bundle heat exchanger 30 described in any of the foregoing embodiments. The piston engine 10 is a free piston Stirling engine. Specifically, the piston engine 10 comprises an expeller 11, a regenerator 12, a room temperature heat exchanger 13, and a compression cavity. The compression cavity is in communication with the expansion cavity 3121 of the tube bundle heat exchanger 30, and the two limit the piston movement space of the expeller 11. The regenerator 12 is in the form of a ring, is filled in the regenerative cavity 3122 of the tube bundle heat exchanger 30, is arranged outside the expeller 11, and is movably connected with the expeller 11.

[0072] The room temperature heat exchanger 13 is arranged at the end of the regenerator 12 away from the tube bundle heat exchanger 30, is filled in the compression cavity, is arranged outside the expeller 11, and is movably connected with the expeller 11. The end of the compression cavity away from the expansion cavity 3121 is in communication with the inner cavity of the linear motor 20. The connecting rod of the expeller 11 extends from the compression cavity, passes through the inner cavity of the linear motor 20, and abuts against the plate spring at the bottom of the inner cavity of the linear motor 20. The expeller 11 is arranged around the power piston, the permanent magnet, the coil, and the stator, and the like. Specifically, reference can be made to the prior art.

[0073] The working process of the thermoacoustic engine is described as follows.

[0074] From the perspective of working gas: the working gas enters the regenerator 12 through the room temperature heat exchanger 13, absorbs heat in the tube bundle heat exchanger 30 (high temperature heat exchanger), the heat provided by the heating element 32 is transferred to the tube bundle 33 through the liquid metal, the working gas in the tube bundle 33 absorbs the heat, enters the expansion chamber 3121, expands in the expansion chamber 3121, and drives the displacer 11 to move.

[0075] After the displacer 11 moves to the limit position, the displacer 11 moves in the opposite direction under the action of the restoring force provided by the leaf spring, the working gas in the expansion chamber 3121 enters the regenerator 12 through the tube bundle heat exchanger 30, the room temperature heat exchanger 13 cools the working gas that is not reheated to room temperature, the working gas enters the compression chamber to drive the displacer 11 to move, the displacer 11 moves in the opposite direction under the action of the restoring force provided by the leaf spring, and the working gas returns to the room temperature heat exchanger 13 to repeat the cycle.

[0076] From the perspective of acoustic power: in the regenerator 12, part of the heat is converted into acoustic power through the thermoacoustic effect (acoustic power generated due to the temperature difference between the two heat exchangers), and the waste heat is discharged by the room temperature heat exchanger 13. Due to the thermoacoustic effect, acoustic power is generated and amplified in the engine regenerator 12, the acoustic power flows through the tube bundle heat exchanger 30 into the expansion chamber 3121, the displacer 11 feeds back the acoustic power of the expansion chamber 3121 to the compression chamber, and adjusts the phase of the acoustic power flow in the regenerator 12 to tend to be a traveling wave phase.

[0077] The acoustic power flow of the compression chamber part of the acoustic power flow is returned to the regenerator 12 through the room temperature heat exchanger 13 to continue to be amplified, and the other part is converted into effective electric power output by the power piston. In addition, the remaining acoustic power is transmitted to the back cavity through the power piston, and a part of the acoustic power in the back cavity can be recovered by the connecting rod of the displacer 11. Therefore, after the displacer 11 collects the acoustic power from the expansion chamber 3121 and the acoustic power from the motor back cavity, it transmits the acoustic power to the compression chamber. During the transmission process, the displacer 11 consumes a small part of the acoustic power due to the mechanical damping, and the remaining part enters the room temperature heat exchanger 13 and is amplified again in the regenerator 12, repeating the above cycle. The energy used to drive the thermoelectric conversion cycle comes from the heat of the tube bundle heat exchanger 30, and the waste heat is taken away by the room temperature heat exchanger 13.

[0078] It can be understood that the thermoacoustic engine of the embodiment of the present application also has the beneficial effects of the tube bundle heat exchanger 30 in any of the foregoing embodiments because it includes the tube bundle heat exchanger 30 described in any of the foregoing embodiments. Specifically, please refer to the foregoing description, which will not be repeated here.

[0079] Figure 5is a half-section schematic view of two tube bundle heat exchangers arranged in opposition provided by an embodiment of the present application; Figure 6 is a full-section schematic view of two tube bundle heat exchangers arranged in opposition provided by an embodiment of the present application.

[0080] Referring to Figure 5 and Figure 6 In an optional embodiment of the present application, two tube bundle heat exchangers 30 are provided, and the two tube bundle heat exchangers 30 are arranged in opposition, wherein the heat exchange cavities 311 of the two tube bundle heat exchangers 30 are in communication with each other, and the working cavities 312 of the two tube bundle heat exchangers 30 are in communication with each other.

[0081] It can be understood that, in this way, the vibration and noise of the thermoacoustic heat engine during operation can be reduced, and specifically, because the two tube bundle heat exchangers 30 are arranged in opposition and interact with each other, the flow of liquid metal and heat transfer between them can form a certain balance state, thereby reducing the system instability factors caused by vibration and noise, and helping to improve the overall reliability of the thermoacoustic heat engine. It should be noted that the tube bundle heat exchangers 30 arranged in opposition can be adjusted and optimized according to different working condition requirements to meet different thermoacoustic conversion efficiency and heat exchange performance requirements, which can effectively improve the adaptability and flexibility of the thermoacoustic heat engine.

[0082] In an optional embodiment of the present application, the thermoacoustic heat engine further comprises a heat pipe, one end of the heat pipe is connected with the remote heat source, the other end of the heat pipe is connected with the heat exchange cavity 311 of the tube bundle heat exchanger 30, and the heat pipe is used for transferring heat; the heat pipe can transfer heat from the nuclear heat source or other remote heat source to the liquid metal in the heat exchange cavity 311. The core working principle of the heat pipe is based on phase change heat conduction, that is, heat is transferred through the evaporation and condensation process of the fluid, and specifically, the existing technology can be referred to for adaptive design.

[0083] It should be noted that after the calibration process is completed, the heating element 32 in the foregoing embodiment can be removed, and the heating element 32 in the foregoing embodiment is replaced by a heat pipe; it can be understood that in the prior art, the remote heat source is generally loaded by a heat fluid, however, the circulation of the heat fluid needs a pump to provide kinetic energy, and a general pump cannot adapt to a high-temperature environment, and a pump resistant to high temperature is too high in cost, in the present embodiment, the heat pipe can be used to transfer heat from the remote heat source to the liquid metal in a non-active way, which can efficiently transfer heat from the remote heat source and is not limited by the pump.

[0084] Figure 7 is a flowchart of a heat exchange performance calibration method of a tube bundle heat exchanger provided by an embodiment of the present application.

[0085] Referring to Figure 7The third aspect of the embodiment of the present application provides a heat exchange performance calibration method of the tube bundle heat exchanger 30, which is referred to as a calibration method hereinafter; the calibration method specifically comprises the following steps.

[0086] S100: set the initial power of the heating element 32 and the flow rate of the working gas.

[0087] Specifically, before starting the calibration, the flow rate of the working gas and the initial power output of the plurality of heating elements 32 need to be set first. It should be noted that the positions of different heating elements 32 are different, and the heating element 32 close to the position of the inlet of the working body may have a larger temperature difference, which may lead to a stronger heat exchange performance, so different heating powers can be provided to the heating elements 32 according to the positions of the heating elements 32.

[0088] Secondly, in this step, temperature sensors, flow sensors and pressure sensors also need to be installed. Specifically, temperature sensors, flow sensors and pressure sensors can be installed at different positions of the tube bundle heat exchanger 30 (such as the inlet of the tube bundle 33, the outlet of the tube bundle 33, the inside of the tube bundle 33, etc.) to monitor the state of the working gas and the heat exchange surface in real time.

[0089] S200: according to the preset target, select a single or multiple heating elements 32, adjust the power of each heating element 32 one by one, and collect the heat exchange data of the working gas.

[0090] Specifically, the actual power of different heating elements 32 can be adjusted according to the simulated working condition, i.e. the preset target, so that the heat distribution in the heat exchange cavity 311 matches the simulated working condition; in this process, the temperature, pressure and flow rate of the working gas at each position and other heat exchange data need to be collected in real time through the aforementioned temperature sensors, flow sensors and pressure sensors.

[0091] S300: calculate the heat exchange efficiency of the tube bundle heat exchanger 30 according to the heat exchange data.

[0092] In this step, the heat exchange efficiency of the tube bundle heat exchanger 30 can be calculated according to the temperature, pressure and flow rate and other heat exchange data obtained in the previous step, combined with the calculation formula in the prior art. For specific calculation methods, please refer to the prior art.

[0093] It can be understood that in actual application, the heat output of the combustion heat source has complexity, and the heat flow size, temperature distribution and heat transfer mode thereof will change with the change of the combustion process, for example, the fuel type, combustion intensity and burner structure and other factors will affect the combustion heat exchange, and the traditional calibration method usually calibrates through preset fixed temperature difference, flow rate and other conditions to obtain a group of data. This way is difficult to accurately reproduce this complex heat input condition, resulting in a large deviation between the calibration result and the actual running performance.

[0094] The heat exchange performance calibration method of the tube bundle heat exchanger 30 provided by the embodiment of the present application can select a single or multiple heating elements 32 according to a preset target, and adjust the actual power of each heating element 32, so as to simulate the dynamic heat load changes caused by the actual combustion phenomena such as the strength change of the combustion flame and the movement of the combustion area, and further accurately simulate the heat input changes at different moments and in different areas in the combustion process. The flexible adjustment mode enables the tube bundle heat exchanger 30 to experience a similar heat load change process as the actual combustion heat exchange in the calibration process, thereby providing a basis for accurately measuring the heat exchange performance.

[0095] Secondly, in the combustion process, the heat is unevenly distributed around the burner. By reasonably controlling the power of the heating elements 32 at different positions, a similar uneven heat distribution can be formed in the heat exchange cavity 311, which enables the liquid metal and the tube bundle 33 in the heat exchanger to work in a similar temperature field as the actual combustion heat exchange, thereby more accurately reflecting the heat exchange performance of the liquid metal and the tube bundle 33 under the actual combustion heat source.

[0096] In addition, by controlling the power of a single or multiple heating elements 32, various working conditions that the heat exchanger may encounter in actual operation can be covered. Whether it is a start-up, stable operation or load change condition, the corresponding heat input change can be simulated by adjusting the power of the heating elements 32. The extensive working condition simulation capability enables the heat exchange performance of the tube bundle heat exchanger 30 to be accurately measured under various actual working conditions, thereby improving the practicality and representativeness of the heat exchange performance calibration measurement results.

[0097] Meanwhile, the method is not only suitable for simulating the combustion heat source, but also can adapt to other types of heat sources by adjusting the power of the heating elements 32. For example, for a nuclear heat device and other long-distance heat sources, although the heat output characteristics are different from the combustion heat source, the heat input to the tube bundle heat exchanger 30 can still be simulated by reasonably setting the power and working mode of the heating elements 32. The adaptability to multiple heat sources enables the heat exchange performance of the tube bundle heat exchanger 30 to be accurately evaluated under different energy application scenarios, thereby widening the application range of the tube bundle heat exchanger 30 and improving the comprehensiveness of the performance evaluation.

[0098] In an optional embodiment of the present application, the step of calculating the heat exchange efficiency of the tube bundle heat exchanger 30 according to the heat exchange data further comprises: adjusting the power distribution of each heating element 32 through a feedback mechanism to determine the optimal heat exchange performance of the tube bundle heat exchanger 30 under different working conditions.

[0099] It can be understood that after the heat exchange efficiency is calculated, if it is found that the current heat exchange efficiency does not reach the expected target or there is uneven heat exchange in some areas, the power output of the corresponding heating element 32 can be adjusted, and through continuous feedback adjustment, the optimal heat exchange performance of the heat exchanger under different working conditions can be determined, and thus the overall performance and adaptability of the tube bundle heat exchanger 30 can be improved.

[0100] It should be noted that the technical solutions in various embodiments of the present application can be combined with each other, but the basis for the combination is that it can be realized by a person skilled in the art; when the combination of technical solutions is contradictory or cannot be realized, it should be considered that the combination of technical solutions does not exist, that is, it is not within the protection scope of the present application.

[0101] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for some technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for calibrating heat exchange performance of a tube bundle heat exchanger, characterized in that, The method comprises the following steps: setting initial power of the heating element (32) and flow rate of the working gas; selecting single or multiple heating elements (32) according to preset targets, adjusting power of each heating element (32) one by one, and collecting heat exchange data of the working gas; calculating heat exchange efficiency of the tube bundle heat exchanger according to the heat exchange data; adjusting power distribution of each heating element (32) through a feedback mechanism to determine optimal heat exchange performance of the tube bundle heat exchanger under different working conditions; The tube bundle heat exchanger comprises: a shell (31) comprising a heat exchange cavity (311) and a working cavity (312), the heat exchange cavity (311) is spaced apart from the working cavity (312), and the heat exchange cavity (311) is provided with liquid metal; a heating element (32) penetrating the heat exchange cavity (311) and used for heating the liquid metal; a tube bundle (33) penetrating the heat exchange cavity (311) and spaced apart from the heating element (32), the openings at both ends of the tube bundle (33) are in communication with the working cavity (312), and the tube bundle (33) is used for transmitting working gas; The heating element (32) is provided with multiple heating elements (32) which are spaced apart in the heat exchange cavity (311), and each heating element (32) can be independently controlled.

2. The method of calibrating heat exchange performance of a tube bundle heat exchanger according to claim 1, wherein The extension direction of the heating element (32) is perpendicular to the axis of the heat exchange cavity (311), and multiple heating elements (32) are uniformly spaced along the axis of the heat exchange cavity (311).

3. The method of claim 1, wherein The working cavity (312) comprises an expansion cavity (3121) and a regenerative cavity (3122), the heat exchange cavity (311) is arranged around the expansion cavity (3121), and a support (34) is arranged between the cavity wall of the expansion cavity (3121) and the cavity wall of the heat exchange cavity (311); The regenerative cavity (3122) is arranged on the side of the expansion cavity (3121) away from the support (34), the opening at one end of the tube bundle (33) is in communication with the regenerative cavity (3122), and the opening at the other end of the tube bundle (33) is in communication with the expansion cavity (3121).

4. The method of claim 3, wherein The extension direction of the heating element (32) is parallel to the axis of the heat exchange cavity (311), and multiple heating elements (32) are spaced apart around the axis of the heat exchange cavity (311).

5. A thermoacoustic heat engine characterized by, The tube bundle heat exchanger comprises the tube bundle heat exchanger according to any one of the preceding claims 1 to 4.

6. The thermo-acoustic heat engine of claim 5, wherein, The tube bundle heat exchanger (30) is provided with two tube bundle heat exchangers which are oppositely arranged; The two heat exchange cavities (311) are in communication with each other, and the two working cavities (312) are in communication with each other.

7. The thermo-acoustic heat engine of claim 5, wherein, Further comprising a heat pipe, one end of the heat pipe is connected with a remote heat source, the other end of the heat pipe is connected with the heat exchange cavity (311) of the tube bundle heat exchanger, and the heat pipe is used for transferring heat.

Images