Tube bundle type heat exchanger, heat exchange performance calibration method of tube bundle type heat exchanger and thermoacoustic engine

Abstract

The invention relates to the technical field of heat exchange equipment, and provides a tube bundle type heat exchanger, a heat exchange performance calibration method thereof and a thermo-acoustic engine. The tube bundle type heat exchanger comprises a shell, a heating piece and a tube bundle, the shell comprises a heat exchange cavity and a working cavity, the heat exchange cavity and the working cavity are arranged at an interval, and liquid metal is arranged in the heat exchange cavity; the heating piece penetrates through the heat exchange cavity and is used for heating the liquid metal; the tube bundle penetrates through the heat exchange cavity and is spaced from the heating piece, openings in the two ends of the tube bundle communicate with the working cavity, and the tube bundle is used for conveying working gas. According to the tube bundle type heat exchanger, a uniform temperature field is formed through the combination of the heating piece and the liquid metal, the power of the heating piece can be directly used as reference data for measuring the heat exchange performance of the tube bundle type heat exchanger, and heat sources such as high-temperature flames and high-temperature flue gas do not participate in the heat exchange process of the tube bundle type heat exchanger; in other words, complex radiation and convective heat exchange modes do not exist, and the difficulty of accurate evaluation of the performance of the heat exchanger is effectively reduced.

Description

Technical Field

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

[0002] A thermoacoustic heat engine is a device that uses the thermoacoustic effect to directly convert thermal energy into acoustic energy or mechanical energy. This conversion process is based on the generation of sound waves by gas under the action of a periodic temperature gradient. As the heat input end of a thermoacoustic heat engine, the high-temperature heat exchanger faces the challenges of high heat flux density and a complex working environment. 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 a thermoacoustic heat engine. In a thermoacoustic heat engine driven by fuel, the tube bundle heat exchanger mainly achieves heat transfer through its internal tube bundle structure.

[0003] 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 of the tube bundle heat exchanger. However, the complex radiation and convection heat transfer of the high-temperature flame and high-temperature flue gas brings great difficulties to the accurate evaluation of the heat exchanger performance. Summary of the invention

[0004] The first aspect of the present invention provides a tube bundle heat exchanger to solve the defect of the direct combination of the tube bundle heat exchanger and 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 transfer performance of the tube bundle heat exchanger. In the heat transfer process of the tube bundle heat exchanger, there is no participation of heat sources such as high-temperature flames and high-temperature flue gas, that is, there is no complex radiation and convection heat transfer mode, which effectively reduces the difficulty of accurately evaluating the performance of the heat exchanger.

[0005] A second aspect of the present invention provides a thermoacoustic heat engine.

[0006] A third aspect of the present invention provides a method for calibrating the heat exchange performance of a tube bundle heat exchanger.

[0007] The tube bundle heat exchanger provided by the present invention comprises: The shell comprises a heat exchange chamber and a working chamber, wherein the heat exchange chamber is spaced apart from the working chamber, and liquid metal is arranged in the heat exchange chamber; A heating element, which is arranged in the heat exchange cavity and is used to heat the liquid metal; A tube bundle is arranged in the heat exchange cavity and is spaced apart from the heating element. Openings at both ends of the tube bundle are communicated with the working cavity. The tube bundle is used to transmit the working gas.

[0008] According to the tube bundle heat exchanger provided by the present invention, a plurality of the heating elements are provided, the plurality of the heating elements are arranged at intervals in the heat exchange cavity, and each of the heating elements can be independently controlled.

[0009] According to the tube bundle heat exchanger provided by the present invention, the extending direction of the heating element is perpendicular to the axis of the heat exchange cavity, and a plurality of the heating elements are evenly spaced apart along the axis of the heat exchange cavity.

[0010] According to the tube bundle heat exchanger provided by the present invention, the working chamber includes an expansion chamber and a heat recovery chamber, the heat exchange chamber is arranged around the expansion chamber, and a support is arranged between the chamber wall of the expansion chamber and the chamber wall of the heat exchange chamber; The heat recovery chamber is arranged on a side of the expansion chamber away from the support member, an opening at one end of the tube bundle is communicated with the heat recovery chamber, and an opening at the other end of the tube bundle is communicated with the expansion chamber.

[0011] According to the tube bundle heat exchanger provided by the present invention, the extension direction of the heating element is parallel to the axis of the heat exchange cavity, and a plurality of the heating elements are arranged at intervals around the axis of the heat exchange cavity.

[0012] The thermoacoustic heat engine provided by the present invention comprises the tube bundle heat exchanger described in any one of the above items.

[0013] According to the thermoacoustic heat engine provided by the present invention, two tube bundle heat exchangers are provided, and the two tube bundle heat exchangers are arranged opposite to each other; Wherein, the two heat exchange chambers are connected to each other, and the two working chambers are connected to each other.

[0014] The thermoacoustic heat engine provided according to the present invention further comprises a heat pipe, one end of which is used to be connected to a remote heat source, and the other end of which is connected to the heat exchange cavity of the tube bundle heat exchanger, and the heat pipe is used to transfer heat.

[0015] The present invention provides a method for calibrating the heat exchange performance of a tube bundle heat exchanger, comprising: Set the initial power of the heating element and the flow rate of the working gas; According to a preset target, select a single or multiple heating elements, adjust the power of each heating element one by one, and collect heat exchange data of the working gas; Calculate the heat transfer efficiency of the tube bundle heat exchanger based on the heat exchange data.

[0016] According to the heat exchange performance calibration method of the tube bundle heat exchanger provided by the present invention, after the step of calculating the heat exchange efficiency of the tube bundle heat exchanger according to the heat exchange data, the method further comprises: The power distribution of each of the heating elements is adjusted through a feedback mechanism to determine the optimal heat exchange performance of the tube bundle heat exchanger under different working conditions.

[0017] The tube bundle heat exchanger provided by the present invention, when used for calibration, the working gas in the working chamber can enter the heat exchange chamber through the tube bundle, and when the heating element heats the liquid metal, the liquid metal and the working gas can exchange heat through the wall of the tube bundle. By accurately controlling the power of the heating element and collecting the temperature, pressure and flow data of the working gas inside and outside the tube bundle in real time, the heat exchange efficiency of the tube bundle heat exchanger can be directly and accurately measured, thereby realizing the calibration of the heat exchanger performance.

[0018] Secondly, since liquid metal has a large heat capacity, high thermal conductivity, and can flow freely in the heat exchange chamber, when the heating element 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 wraps the tube bundle in all directions, the uniform temperature field can quickly and evenly distribute the heat to the tube bundles at various positions in the heat exchange chamber. In this way, on the one hand, it can ensure that the working gas in the tube bundle can be heated evenly at different positions. This uniform heat exchange characteristic can make the temperature, pressure and flow changes of the working gas in the heat exchanger more consistent, reducing the data deviation caused by local uneven heat exchange; on the other hand, it can improve the consistency of the temperature of each point on the surface of the tube bundle, avoid the concentration of thermal stress caused by local overheating or overcooling, and greatly reduce the risk of damage to the tube bundle structure caused by thermal stress caused by uneven temperature.

[0019] In addition, due to the negative temperature expansion characteristic of liquid metal, when the heating element heats the liquid metal, the volume of the liquid metal will not expand, but will gradually shrink as the temperature rises. This can effectively reduce the stress of the liquid metal on the wall of the heat exchange chamber, thereby improving the overall safety of the tube bundle heat exchanger.

[0020] Compared with the form of direct combination of heat exchanger and burner in the prior art, in the tube bundle heat exchanger provided by the embodiment of the present invention, 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. There is no participation of heat sources such as high-temperature flames and high-temperature flue gas in the heat exchange process of the tube bundle heat exchanger. That is, in the heat exchange process, there is no complex radiation and convection heat transfer mode, nor is there an effect of high temperature on the radiated surface and low temperature on the back radiation surface, which effectively reduces the difficulty of accurate evaluation of the heat exchanger performance.

[0021] Secondly, in order to ensure the pressure bearing capacity of the tube bundle, the tube bundle in the prior art is generally made of stainless steel. Considering the heat conductivity problem, the tube bundle is generally made of thinner wall thickness, which leads to a very fast response of the tube bundle to the flame heat source. When the tube bundle heat exchanger is used in a thermoacoustic heat engine, this will cause great difficulties in controlling the moving parts. At the same time, due to the fast response of the tube bundle to the heat source, the temperature of the tube bundle will change frequently, which will further aggravate the creep failure problem of the tube bundle material. In the embodiment of the present invention, due to the presence of liquid metal, the heating element will not directly contact the tube bundle, 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. In this way, on the one hand, when the tube bundle heat exchanger is used in a thermoacoustic heat engine, a smooth transition can be provided for the stroke control of the moving parts, that is, the difficulty of controlling the moving parts can be effectively reduced; on the other hand, the thermal stress borne by the tube bundle material can be reduced, and the creep failure of the tube bundle material can be slowed down, thereby effectively improving the sealing and overall performance of the tube bundle heat exchanger. In addition, the close combination of the liquid metal and the tube bundle through the fluid domain and the solid domain can make the tube bundle have no obvious constraints in the pressure-bearing direction, reduce the stress on the tube bundle, and improve the safety of the tube bundle. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 It is a schematic diagram of the cross-sectional structure of the tube bundle heat exchanger provided in an embodiment of the present invention at a certain angle.

[0024] Figure 2 It is a cross-sectional schematic diagram of the tube bundle heat exchanger provided by an embodiment of the present invention at another angle.

[0025] Figure 3 It is a schematic diagram of the layout of another structure of the heating element provided in an embodiment of the present invention.

[0026] Figure 4 It is a schematic cross-sectional structure diagram of a thermoacoustic heat engine provided in an embodiment of the present invention.

[0027] Figure 5 It is a half-section schematic diagram of two tube bundle heat exchangers arranged opposite to each other provided by an embodiment of the present invention.

[0028] Figure 6 It is a full cross-sectional schematic diagram of two tube bundle heat exchangers arranged opposite to each other according to an embodiment of the present invention.

[0029] Figure 7 It is a flow chart of a method for calibrating the heat exchange performance of a tube bundle heat exchanger provided in an embodiment of the present invention.

[0030] Reference numerals: 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 chamber; 312: working chamber; 3121: expansion chamber; 3122: regenerator chamber; 32: heating element; 33: tube bundle; 34: support element. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] In the description of the embodiments of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0033] In the embodiments of the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean 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, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0034] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiments of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0035] 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 of the high-temperature flame and high-temperature flue gas makes it extremely difficult to accurately evaluate 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 easily affected by the heat source, which brings difficulties 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 be subjected to extremely high thermal stress, aggravating the creep failure of the heat exchanger material, and further affecting the sealing and overall performance of the heat exchanger. In addition, the tube bundle heat exchanger naturally has the effect of high temperature on the radiation surface and low temperature on the back radiation surface, which makes the working gas in the pipeline unable to be heated evenly, affecting the heat exchange effect.

[0036] Figure 1 It is a schematic diagram of the cross-sectional structure of the tube bundle heat exchanger provided in an embodiment of the present invention at a certain angle.

[0037] See also Figure 1 A first aspect of an embodiment of the present invention provides a tube bundle heat exchanger 30 for solving at least one of the above-mentioned technical problems; the tube bundle heat exchanger 30 includes a shell 31, a heating element 32 and a tube bundle 33, the shell 31 is a hollow structure, the hollow structure includes a heat exchange chamber 311 and a working chamber 312, the heat exchange chamber 311 and the working chamber 312 are arranged at intervals and are not connected to each other, the heat exchange chamber 311 is filled with a large amount of liquid metal, the liquid metal can flow freely in the heat exchange chamber 311, and the specific content of the liquid metal can be adaptively selected according to actual conditions.

[0038] The heating element 32 is passed through the heat exchange cavity 311. The heating element 32 is in direct contact with the liquid metal and is completely wrapped by the liquid metal. The heating element 32 is used to heat the liquid metal. The heating element 32 can select existing heating devices such as heating plates or heating tubes. The tube bundle 33 is passed through the heat exchange cavity 311 and is spaced apart from the heating element 32. It is also completely wrapped by the liquid metal. The openings at both ends of the tube bundle 33 are connected to the working cavity 312. The tube bundle 33 is used to transmit the working gas.

[0039] See also Figure 1 It can be understood that when the tube bundle heat exchanger 30 provided by the present invention is used for calibration, the working gas in the working chamber 312 can enter the heat exchange chamber 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 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 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, thereby realizing the calibration of the heat exchanger performance.

[0040] Secondly, since the liquid metal has a large heat capacity and a high thermal conductivity, and can flow freely in the heat exchange chamber 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 wraps the tube bundle 33 in all directions, the uniform temperature field can quickly and evenly distribute the heat to the tube bundle 33 at various positions in the heat exchange chamber 311. In this way, on the one hand, it can ensure that the working gas in the tube bundle 33 can be heated evenly at different positions. This uniform heat exchange characteristic can make the temperature, pressure and flow changes of the working gas in the heat exchanger more consistent, reducing the data deviation caused by local uneven 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, avoid the thermal stress concentration caused by local overheating or overcooling, and greatly reduce the risk of damage to the structure of the tube bundle 33 caused by thermal stress caused by uneven temperature.

[0041] In addition, due to the negative temperature expansion characteristic of liquid metal, when the heating element 32 heats the liquid metal, the volume of the liquid metal will not expand, but will gradually shrink as the temperature rises. In this way, the stress of the liquid metal on the wall of the heat exchange chamber 311 can be effectively reduced, thereby improving the overall safety of the tube bundle heat exchanger 30.

[0042] Compared with the form of direct combination of the heat exchanger and the burner in the prior art, in the tube bundle heat exchanger 30 provided by the embodiment of the present invention, 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. There is no participation of heat sources such as high-temperature flames and high-temperature flue gas in the heat exchange process of the tube bundle heat exchanger 30, that is, there is no complex radiation and convection heat transfer mode in the heat exchange process, and there is no effect of high temperature on the radiated surface and low temperature on the back radiation surface, which effectively reduces the difficulty of accurate evaluation of the heat exchanger performance.

[0043] Secondly, in order to ensure the pressure bearing capacity of the tube bundle 33, the tube bundle 33 in the prior art is generally made of stainless steel. Considering the heat conductivity problem, the tube bundle 33 is generally made thinner, which causes the tube bundle 33 to respond very quickly to the flame heat source. When the tube bundle heat exchanger 30 is used in a thermoacoustic heat engine, it will cause great difficulties in controlling the moving parts. At the same time, due to the rapid 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 invention, due to the presence of liquid metal, The heating element 32 will not directly contact the tube bundle 33. 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. In this way, on the one hand, when the tube bundle heat exchanger 30 is used in a thermoacoustic heat engine, it can provide a smooth transition for the stroke control of the moving parts, that is, it can effectively reduce the difficulty of forming control of the moving parts; on the other hand, it can reduce the thermal stress of the tube bundle 33 material, slow down the creep failure of the tube bundle 33 material, and thus effectively improve the sealing and overall performance of the tube bundle heat exchanger 30. In addition, the close combination of the liquid metal and the tube bundle 33 through the fluid domain and the solid domain can make the tube bundle 33 have no obvious constraints in the pressure direction, reduce the stress borne by the tube bundle 33, and improve the safety of the tube bundle 33.

[0044] In optional embodiments of the present invention, the liquid metal may be selected from sodium potassium alloy, gallium indium tin, molybdenum alloy, tungsten alloy, bismuth and alloys thereof. It can be understood that, compared with conventional heat conducting media, the heat capacity of liquid metal is larger and the upper temperature limit that it can withstand is higher, so that heat storage can be performed effectively.

[0045] Figure 2 It is a cross-sectional schematic diagram of the tube bundle heat exchanger provided by an embodiment of the present invention at another angle.

[0046] See also Figure 1 and Figure 2 In an optional embodiment of the present invention, a plurality of heating elements 32 are provided, and the plurality of heating elements 32 are arranged at intervals in the heat exchange chamber 311, and each heating element 32 can be controlled independently. It is understandable that different heating elements 32 are distributed at different positions, and different heating powers can be provided to the heating elements 32 according to the distribution positions of the heating elements 32, and the heating power can be increased in areas that require more heat, and reduced in areas that require less heat. In this way, the heat distribution in the entire heat exchange chamber 311 can be made more reasonable, and the uniformity of the entire temperature field can be ensured.

[0047] In addition, in actual applications, the heat output of the combustion heat source is complex. Its heat flow rate, temperature distribution, and heat transfer method will change with the combustion process. For example, factors such as fuel type, combustion intensity, and burner structure will affect the combustion heat exchange rate. The traditional calibration method usually calibrates by pre-setting fixed temperature difference, flow rate and other conditions to obtain a set of data. This method is difficult to accurately replicate this complex heat input situation, resulting in a large deviation between the calibration results and the actual operating performance.

[0048] In the embodiment of the present invention, by controlling the power of a single or multiple heating elements 32, the dynamic heat load changes caused by actual combustion phenomena such as the change in the intensity of the combustion flame and the movement of the combustion area can be simulated, and the heat input changes at different times and in different areas during the combustion process can be accurately simulated. This flexible adjustment method allows the tube bundle heat exchanger 30 to experience a heat load change process similar to the actual combustion heat exchange during the calibration process, providing a basis for accurately measuring the heat exchange performance.

[0049] Secondly, during the combustion process, the distribution of heat around the burner is uneven. 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. This enables the liquid metal and tube bundle 33 in the heat exchanger to operate in a temperature field similar to the actual combustion heat exchange, thereby more accurately reflecting its heat exchange performance under the actual combustion heat source.

[0050] In addition, the power of a single or multiple heating elements 32 can cover various operating conditions that the heat exchanger may encounter in actual operation. Whether it is startup, stable operation or load change, the corresponding heat input change can be simulated by adjusting the power of the heating element 32. This wide range of operating condition simulation capabilities enables the heat transfer performance of the tube bundle heat exchanger 30 to be accurately measured under a variety of actual working conditions, thereby improving the practicality and representativeness of the heat transfer performance calibration measurement results.

[0051] At the same time, this method is not only suitable for simulating combustion heat sources, but can also adapt to other types of heat sources by adjusting the power of the heating element 32. For example, for long-distance heat sources such as nuclear thermal devices, although their heat output characteristics are different from those of combustion heat sources, by reasonably setting the power and working mode of the heating element 32, its heat input to the tube bundle heat exchanger 30 can still be simulated. This adaptability to multiple heat sources enables the heat transfer performance of the tube bundle heat exchanger 30 in different energy application scenarios to be accurately evaluated, which broadens the application scope of the tube bundle heat exchanger 30 and the comprehensiveness of performance evaluation.

[0052] In addition, since the heating element 32 does not need to be fixed to the tube bundle 33, the freedom of the layout of the tube bundle 33 can be improved, and the compactness of the structure of the tube bundle heat exchanger 30 can be improved while improving the heat exchange performance, thereby meeting the requirements of the thermoacoustic heat engine for space utilization.

[0053] Continue reading Figure 1 In an optional embodiment of the present invention, the working chamber 312 includes an expansion chamber 3121 and a heat recovery chamber 3122, the heat exchange chamber 311 is arranged around the expansion chamber 3121, and a support member 34 is arranged between the cavity wall of the expansion chamber 3121 and the cavity wall of the heat exchange chamber 311; one or more support members 34 can be provided as long as it does not affect the layout of the heating element 32 and the tube bundle 33.

[0054] The heat recovery chamber 3122 is disposed on a side of the expansion chamber 3121 away from the support member 34, and the heat recovery chamber 3122 can be connected to the expansion chamber 3121. Figure 1 As shown, the heat recovery chamber 3122 and the expansion chamber 3121 can also be separated and arranged. The diameter of the heat recovery chamber 3122 is larger than the diameter of the expansion chamber 3121. The heat recovery chamber 3122 is used to fill the regenerator 12, and the expansion chamber 3121 is used for the ejector 11 to perform piston movement, that is, for the working gas to do work; the opening at one end of the tube bundle 33 is connected to the heat recovery chamber 3122, and the opening at the other end of the tube bundle 33 is connected to the expansion chamber 3121. The working gas can be transmitted in the heat recovery chamber 3122 and the expansion chamber 3121 through the tube bundle 33.

[0055] It can be understood that in the embodiment of the present invention, when the ejector 11 performs piston motion, due to the compression movement of the working gas, the cavity wall of the expansion chamber 3121 will be subjected to a large axial load. The support member 34 provided in this embodiment can play a supporting role and can effectively resist this axial load, thereby ensuring the stability of the expansion chamber 3121.

[0056] Continue reading Figure 1 In an optional embodiment of the present invention, the extension direction of the heating element 32 is perpendicular to the axis of the heat exchange chamber 311, and the plurality of heating elements 32 are evenly spaced along the axis of the heat exchange chamber 311. From another perspective, the plurality of heating elements 32 are inserted into the heat exchange chamber 311 along the side wall of the heat exchange chamber 311 and are extended along the radial direction of the heat exchange chamber 311, that is, the heating elements 32 are arranged transversely. It can be understood that the heating elements 32 arranged in this way can facilitate the disassembly and assembly of the heating elements 32 on the one hand, and can form a uniform temperature field in the heat exchange chamber 311 on the other hand, thereby ensuring uniform heating of the tube bundle 33.

[0057] Figure 3 It is a schematic diagram of the layout of another structure of the heating element provided in an embodiment of the present invention.

[0058] See also Figure 3In an optional embodiment of the present invention, different from the aforementioned embodiment, the extension direction of the heating element 32 is arranged parallel to the axial direction of the heat exchange chamber 311, and a plurality of heating elements 32 are arranged at intervals around the axis of the heat exchange chamber 311. From another perspective, a plurality of heating elements 32 are inserted into the heat exchange chamber 311 along the bottom wall of the heat exchange chamber 311 and extend in a direction parallel to the axis of the heat exchange chamber 311, that is, the heating elements 32 are arranged longitudinally.

[0059] It is understandable that, since the heat exchange chamber 311 is sleeved on the outside of the expansion chamber 3121, the two will restrict an annular chamber. When the liquid metal flows, the annular chamber will play a restrictive role, thereby causing the liquid metal to circulate in the annular chamber. In the embodiment of the present invention, the longitudinal arrangement of the heating elements 32, when the liquid metal flows through these 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, which will cause the liquid metal flow to change the flow direction near the heating element 32, and these turns will cause different parts of the liquid metal fluid to mix together, resulting in a mixing effect. In addition, each time a heating element 32 passes through a heating element 32, turbulence or eddy currents may occur. Such flow changes intensify the material exchange or heat distribution in different areas of the liquid metal, which can make the flow more uniform.

[0060] Figure 4 It is a schematic cross-sectional structure diagram of a thermoacoustic heat engine provided in an embodiment of the present invention.

[0061] See also Figure 4 The second aspect of the embodiment of the present invention provides a thermoacoustic heat engine, which includes a piston engine 10, a linear motor 20 and the tube bundle heat exchanger 30 described in any of the above embodiments; the piston engine 10 is a free piston Stirling engine, specifically, the piston engine 10 includes an ejector 11, a regenerator 12, a room temperature heat exchanger 13 and a compression chamber, the compression chamber is connected to the expansion chamber 3121 of the tube bundle heat exchanger 30, and the two limit the piston movement space of the ejector 11, the regenerator 12 is an annular structure, the regenerator 12 is filled in the regeneration chamber 3122 of the tube bundle heat exchanger 30, and the regenerator 12 is sleeved on the outside of the ejector 11, and the two are movably matched.

[0062] The room temperature heat exchanger 13 is arranged at one end of the regenerator 12 away from the tube bundle heat exchanger 30, and is filled in the compression chamber. At the same time, it is also sleeved on the outside of the ejector 11 and cooperates with the ejector 11; the end of the compression chamber away from the expansion chamber 3121 is connected to the inner cavity of the linear motor 20. The connecting rod of the ejector 11 starts from the compression chamber, passes through the inner cavity of the linear motor 20, and then abuts against the leaf spring at the bottom of the inner cavity of the linear motor 20. The outside of the ejector 11 is surrounded by components such as a power piston, a permanent magnet, a coil and a stator. For details, please refer to the prior art.

[0063] The working process of the thermoacoustic heat engine is described below.

[0064] From the perspective of the working gas: the working gas enters the regenerator 12 through the room temperature heat exchanger 13, and enters the tube bundle heat exchanger 30 (high temperature heat exchanger) through the regenerator 12 to absorb heat. The heat provided by the heating element 32 is transferred to the tube bundle 33 through liquid metal. The working gas in the tube bundle 33 absorbs heat, enters the expansion chamber 3121, expands in the expansion chamber 3121, and pushes the ejector 11 to move.

[0065] After the ejector 11 moves to the extreme position, under the action of the restoring force provided by the leaf spring, the ejector 11 moves in the opposite direction, and the working gas in the expansion chamber 3121 enters the regenerator 12 through the tube bundle heat exchanger 30 for reheating, and the room temperature heat exchanger 13 cools the unreheated working gas to room temperature, and the working gas enters the compression chamber to drive the ejector 11 to move. Under the action of the restoring force provided by the leaf spring, the ejector 11 moves in the opposite direction, and the working gas returns to the room temperature heat exchanger 13 to repeat the cycle.

[0066] From the perspective of acoustic work: in the regenerator 12, heat is partially converted into acoustic work through the thermoacoustic effect (acoustic work is 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 work is generated and amplified in the engine regenerator 12, and the acoustic work flows through the tube bundle heat exchanger 30 into the expansion chamber 3121. The ejector 11 feeds back the acoustic work of the expansion chamber 3121 to the compression chamber, and adjusts the phase of the acoustic work flow in the regenerator 12 to make it tend to the traveling wave phase.

[0067] Part of the acoustic power flow of the compression chamber flows back to the regenerator 12 through the room temperature heat exchanger 13 for further amplification, and the other part is converted into effective electrical power output through the power piston. In addition, the remaining acoustic power is transmitted to the back cavity via the power piston, wherein the connecting rod of the ejector 11 can recover part of the acoustic power from the back cavity. Therefore, the ejector 11 collects the acoustic power of the expansion chamber 3121 and the acoustic power of the motor back cavity, and transmits it to the compression chamber. During the transmission process, due to the mechanical damping of the ejector 11, it consumes a small part of the acoustic power itself. After the remaining part enters the room temperature heat exchanger 13, it is amplified again in the regenerator 12, and the above cycle is repeated, wherein the energy used to drive the thermoelectric conversion cycle comes from the heat of the tube bundle heat exchanger 30, and the waste heat generated is taken away by the room temperature heat exchanger 13.

[0068] It can be understood that the thermoacoustic heat engine of the embodiment of the present invention, because it includes the tube bundle heat exchanger 30 described in any of the aforementioned embodiments, also has the beneficial effects of the tube bundle heat exchanger 30 in any of the aforementioned embodiments. For details, please refer to the above description, which will not be repeated here.

[0069] Figure 5is a half-section schematic diagram of two tube bundle heat exchangers arranged opposite to each other provided by an embodiment of the present invention; Figure 6 It is a full cross-sectional schematic diagram of two tube bundle heat exchangers arranged opposite to each other according to an embodiment of the present invention.

[0070] See also Figure 5 and Figure 6 In an optional embodiment of the present invention, two tube bundle heat exchangers 30 are provided, and the two tube bundle heat exchangers 30 are arranged opposite to each other, wherein the heat exchange chambers 311 of the two tube bundle heat exchangers 30 are interconnected, and the working chambers 312 of the two tube bundle heat exchangers 30 are interconnected.

[0071] It is understandable that such a configuration helps to reduce the vibration and noise of the thermoacoustic heat engine during operation. Specifically, since the two tube bundle heat exchangers 30 are placed relative to each other and interact with each other, the liquid metal flow and heat transfer between them will form a certain equilibrium state, thereby reducing the system instability factors caused by vibration and noise, and at the same time helping to improve the overall reliability of the thermoacoustic heat engine. It should be noted that the opposed tube bundle heat exchangers 30 can be adjusted and optimized according to different working conditions to meet different thermoacoustic conversion efficiency and heat exchange performance requirements, which can effectively improve the adaptability and flexibility of the thermoacoustic heat engine.

[0072] In an optional embodiment of the present invention, the thermoacoustic heat engine further includes a heat pipe, one end of which is connected to a remote heat source, and the other end of which is connected to a heat exchange cavity 311 of a tube bundle heat exchanger 30, and the heat pipe is used to transfer heat; the heat pipe can transfer heat from a 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 a fluid, and specifically, the prior art adaptive design can be referred to.

[0073] It should be noted that after the calibration process is completed, the heating element 32 in the aforementioned embodiment can be removed and replaced by a heat pipe; it can be understood that in the prior art, the remote heat source is generally carried by a thermal fluid, however, the circulation of the thermal fluid requires a pump to provide kinetic energy, general pumps cannot adapt to high temperature environments, and the cost of high temperature resistant pumps is too high. In this embodiment, a heat pipe is used to transfer the heat of the remote heat source to the liquid metal in a non-active manner. This method can efficiently transfer the heat of the remote heat source and is not limited by the pump.

[0074] Figure 7 It is a flow chart of a method for calibrating the heat exchange performance of a tube bundle heat exchanger provided in an embodiment of the present invention.

[0075] See also Figure 7A third aspect of an embodiment of the present invention provides a method for calibrating the heat exchange performance of a tube bundle heat exchanger 30, which is referred to as the calibration method in the following text; the calibration method specifically includes the following steps.

[0076] S100: setting the initial power of the heating element 32 and the flow rate of the working gas.

[0077] Specifically, before starting the calibration, it is necessary to first set the flow rate of the working gas and the initial power output of the multiple heating elements 32. It should be noted that different heating elements 32 are distributed at different locations. The heating element 32 near the entrance of the working body may have a stronger heat exchange performance due to a large temperature difference. Therefore, different heating powers can be provided to the heating element 32 according to its distribution location.

[0078] Secondly, in this step, it is also necessary to install temperature sensors, flow sensors and pressure sensors. 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 status of the working gas and the heat exchange surface in real time.

[0079] S200: According to a preset target, select a single or multiple heating elements 32, adjust the power of each heating element 32 one by one, and collect heat exchange data of the working gas.

[0080] Specifically, the actual power of different heating elements 32 can be adjusted according to the working conditions to be simulated, that is, the preset target, so that the heat distribution in the heat exchange chamber 311 fits the working conditions to be simulated; in this process, it is also necessary to collect the heat exchange data such as the temperature, pressure and flow rate of the working gas at various positions in real time through the aforementioned temperature sensors, flow sensors and pressure sensors.

[0081] S300: Calculating the heat exchange efficiency of the tube bundle heat exchanger 30 according to the heat exchange data.

[0082] In this step, the heat exchange efficiency of the tube bundle heat exchanger 30 can be calculated based on the heat exchange data such as temperature, pressure and flow rate obtained in the previous step and in combination with the calculation formula in the prior art. For the specific calculation method, please refer to the prior art.

[0083] It is understandable that in actual applications, the heat output of the combustion heat source is complex, and its heat flow rate, temperature distribution, and heat transfer method will change with the combustion process. For example, factors such as fuel type, combustion intensity, and burner structure will affect the combustion heat exchange rate. Traditional calibration methods usually calibrate by pre-setting fixed temperature differences, flow rates, and other conditions to obtain a set of data. This method is difficult to accurately replicate this complex heat input situation, resulting in a large deviation between the calibration results and the actual operating performance.

[0084] In the heat exchange performance calibration method of the tube bundle heat exchanger 30 provided in the embodiment of the present invention, a single or multiple heating elements 32 can be selected according to the preset target, and the actual power of each heating element 32 can be adjusted. This can simulate the dynamic heat load changes caused by actual combustion phenomena such as the intensity changes of the combustion flame and the movement of the combustion area, and then accurately simulate the heat input changes at different times and in different areas during the combustion process. This flexible adjustment method enables the tube bundle heat exchanger 30 to experience a heat load change process similar to the actual combustion heat exchange during the calibration process, providing a basis for accurately measuring the heat exchange performance.

[0085] Secondly, during the combustion process, the distribution of heat around the burner is uneven. 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. This enables the liquid metal and tube bundle 33 in the heat exchanger to operate in a temperature field similar to the actual combustion heat exchange, thereby more accurately reflecting its heat exchange performance under the actual combustion heat source.

[0086] In addition, by controlling the power of a single or multiple heating elements 32, various operating conditions that the heat exchanger may encounter in actual operation can be covered. Whether it is startup, stable operation or load change, the corresponding heat input change can be simulated by adjusting the power of the heating element 32. This wide range of operating condition simulation capabilities enables the heat transfer performance of the tube bundle heat exchanger 30 to be accurately measured under a variety of actual working conditions, thereby improving the practicality and representativeness of the heat transfer performance calibration measurement results.

[0087] At the same time, this method is not only suitable for simulating combustion heat sources, but can also adapt to other types of heat sources by adjusting the power of the heating element 32. For example, for long-distance heat sources such as nuclear thermal devices, although their heat output characteristics are different from those of combustion heat sources, by reasonably setting the power and working mode of the heating element 32, its heat input to the tube bundle heat exchanger 30 can still be simulated. This adaptability to multiple heat sources enables the heat transfer performance of the tube bundle heat exchanger 30 in different energy application scenarios to be accurately evaluated, thereby broadening the application scope of the tube bundle heat exchanger 30 and the comprehensiveness of performance evaluation.

[0088] In an optional embodiment of the present invention, the step of calculating the heat exchange efficiency of the tube bundle heat exchanger 30 according to the heat exchange data further includes: 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.

[0089] It is understandable that after calculating the heat exchange efficiency, if it is found that the current heat exchange efficiency does not reach the expected target or there are problems such as uneven heat exchange in certain areas, the power output of the corresponding heating element 32 can be adjusted. Through continuous feedback adjustment, the optimal heat exchange performance of the heat exchanger under different working conditions can be determined, thereby improving the overall performance and adaptability of the tube bundle heat exchanger 30.

[0090] It should be noted that the technical solutions in various embodiments of the present invention can be combined with each other, but the basis for the mutual combination is that it can be implemented by ordinary technicians in the field; when the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist, that is, it does not belong to the protection scope of the present invention.

[0091] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A tube bundle heat exchanger, characterized in that: include: The shell (31) comprises a heat exchange chamber (311) and a working chamber (312), wherein the heat exchange chamber (311) and the working chamber (312) are arranged at a distance from each other, and liquid metal is arranged in the heat exchange chamber (311); A heating element (32) is disposed in the heat exchange cavity (311) and is used to heat the liquid metal; A tube bundle (33) is arranged through the heat exchange cavity (311) and is spaced apart from the heating element (32); openings at both ends of the tube bundle (33) are in communication with the working cavity (312); and the tube bundle (33) is used to transmit working gas.

2. The tube bundle heat exchanger according to claim 1, characterized in that: A plurality of the heating elements (32) are provided, and the plurality of the heating elements (32) are arranged at intervals in the heat exchange cavity (311), and each of the heating elements (32) can be independently controlled.

3. The tube bundle heat exchanger according to claim 2, characterized in that: The extending direction of the heating element (32) is perpendicular to the axis of the heat exchange cavity (311), and a plurality of the heating elements (32) are evenly spaced along the axis of the heat exchange cavity (311).

4. The tube bundle heat exchanger according to claim 2, characterized in that: The working chamber (312) comprises an expansion chamber (3121) and a heat recovery chamber (3122); the heat exchange chamber (311) is arranged around the expansion chamber (3121); and a support member (34) is arranged between a chamber wall of the expansion chamber (3121) and a chamber wall of the heat exchange chamber (311); The heat recovery chamber (3122) is arranged on a side of the expansion chamber (3121) away from the support member (34); an opening at one end of the tube bundle (33) is in communication with the heat recovery chamber (3122); and an opening at the other end of the tube bundle (33) is in communication with the expansion chamber (3121).

5. The tube bundle heat exchanger according to claim 4, characterized in that: The extension direction of the heating element (32) is parallel to the axis of the heat exchange cavity (311), and a plurality of the heating elements (32) are arranged at intervals around the axis of the heat exchange cavity (311).

6. A thermoacoustic heat engine, characterized in that: The invention comprises the tube bundle heat exchanger (30) as claimed in any one of claims 1 to 5.

7. The thermoacoustic heat engine according to claim 6, characterized in that Two of the tube bundle heat exchangers (30) are provided, and the two tube bundle heat exchangers (30) are arranged opposite to each other; The two heat exchange chambers (311) are connected to each other, and the two working chambers (312) are connected to each other.

8. The thermoacoustic heat engine according to claim 6, characterized in that: It also includes a heat pipe, one end of which is used to be connected to a remote heat source, and the other end of which is connected to the heat exchange cavity (311) of the tube bundle heat exchanger (30), and the heat pipe is used to transfer heat.

9. A method for calibrating the heat exchange performance of a tube bundle heat exchanger, characterized in that: include Setting the initial power of the heating element (32) and the flow rate of the working gas; According to a preset target, selecting a single or multiple heating elements (32), adjusting the power of each heating element (32) one by one, and collecting heat exchange data of the working gas; The heat exchange efficiency of the tube bundle heat exchanger (30) is calculated based on the heat exchange data.

10. The heat exchange performance calibration method of a tube bundle heat exchanger according to claim 9, characterized in that: After the step of calculating the heat exchange efficiency of the tube bundle heat exchanger (30) according to the heat exchange data, the method further comprises: The power distribution of each heating element (32) is adjusted through a feedback mechanism to determine the optimal heat exchange performance of the tube bundle heat exchanger (30) under different working conditions.

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