Method and equipment for evaluating heat exchange efficiency of tail gas heat exchange structure and medium

Abstract

The invention discloses a heat exchange efficiency evaluation method and device of a tail gas heat exchange structure and a medium, and relates to the field of ammonia hydrogen engine design, and the method comprises the steps that a first-stage three-dimensional model of the designed tail gas heat exchange structure is established based on geometric parameters of the designed tail gas heat exchange structure; material attributes of the designed tail gas heat exchange structure and material attributes of fluid in the designed tail gas heat exchange structure are set in the first-stage three-dimensional model, and a second-stage three-dimensional model is obtained; setting and coupling boundary conditions of the second-stage three-dimensional model on the basis of the working environment parameters to obtain a third-stage three-dimensional model, performing grid division to obtain grid units, and performing finite element simulation analysis to obtain an operation result; and obtaining a heat exchange efficiency evaluation result of the designed tail gas heat exchange structure based on the operation result. According to the method, the heat exchange efficiency of the tail gas heat exchange structure can be accurately and rapidly evaluated, and then the performance of the designed tail gas heat exchange structure can be accurately and rapidly obtained.

Description

Technical Field

[0001] This application relates to the field of ammonia-hydrogen engine design, and particularly to a method, device, and medium for evaluating the heat transfer efficiency of an exhaust gas heat exchange structure. Background Art

[0002] Currently, the evaluation method of the heat transfer efficiency of the exhaust gas heat exchange structure is mainly realized through theoretical calculation based on structural parameters. However, it is difficult to accurately and quickly obtain the performance of the designed structure solely through theoretical calculation. And it is not realistic to obtain data through actual experiments for each design, which will not only increase the evaluation workload and design cost, but also reduce the evaluation efficiency. Summary of the Invention

[0003] The purpose of this application is to provide a method, device, and medium for evaluating the heat transfer efficiency of an exhaust gas heat exchange structure, which can accurately and quickly evaluate the heat transfer efficiency of the exhaust gas heat exchange structure, and then accurately and quickly obtain the performance of the designed exhaust gas heat exchange structure.

[0004] To achieve the above purpose, this application provides the following solutions:

[0005] In the first aspect, this application provides a method for evaluating the heat transfer efficiency of an exhaust gas heat exchange structure, including:

[0006] Obtain the geometric parameters of the designed exhaust gas heat exchange structure, and establish a three-dimensional model of the designed exhaust gas heat exchange structure based on the geometric parameters to obtain the three-dimensional model in the first stage;

[0007] Set the material properties of the designed exhaust gas heat exchange structure and the material properties of the fluid inside the designed exhaust gas heat exchange structure in the three-dimensional model in the first stage to obtain the three-dimensional model in the second stage;

[0008] Set and couple the boundary conditions of the three-dimensional model in the second stage based on the working environment parameters of the designed exhaust gas heat exchange structure to obtain the three-dimensional model in the third stage;

[0009] Perform mesh division on the three-dimensional model in the third stage to obtain mesh elements;

[0010] Perform finite element simulation analysis based on the mesh elements to obtain the operation results;

[0011] Obtain the evaluation result of the heat transfer efficiency of the designed exhaust gas heat exchange structure based on the operation results.

[0012] Optionally, the method for evaluating the heat transfer efficiency of the exhaust gas heat exchange structure is implemented using COMSOL multi-physics simulation software.

[0013] Optionally, the designed exhaust gas heat exchange structure includes an exhaust gas flow region, a heated gas flow region, and a heat transfer wall surface between the regions.

[0014] Optionally, the material properties include the thermal conductivity, constant pressure heat capacity, dynamic viscosity, and density of the fluids in the exhaust gas flow region and the heated gas flow region, as well as the material type, thermal conductivity, constant pressure heat capacity, and density of the heat transfer wall surface between the regions.

[0015] Optionally, the fluid type in the exhaust gas flow region is nitrogen; the fluid type in the heated gas flow region is ammonia.

[0016] Optionally, in the heated gas flow region, the density of ammonia under standard conditions is corrected according to the temperature at each position in the working environment.

[0017] Optionally, the corrected density of ammonia is expressed as:

[0018]

[0019] In the formula, is the corrected density of ammonia, and T is the temperature at each position in the working environment.

[0020] Optionally, a steady-state solver is used to perform finite element simulation analysis based on the grid cells to obtain the operation results.

[0021] In a second aspect, the present application provides a computer device, including: a memory, a processor, and a computer program stored on the memory and executable on the processor, where the processor executes the computer program to implement the steps of the heat transfer efficiency evaluation method of the exhaust gas heat exchange structure provided above.

[0022] In a third aspect, the present application provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the heat transfer efficiency evaluation method of the exhaust gas heat exchange structure provided above are implemented.

[0023] According to the specific embodiments provided by the present application, the present application has the following technical effects:

[0024] The present application provides a heat transfer efficiency evaluation method, device, and medium for an exhaust gas heat exchange structure. By constructing a three-dimensional model of the designed exhaust gas heat exchange structure and performing grid division, finite element simulation analysis is carried out based on the grid cells obtained from the grid division, avoiding the problems of calculation errors that may exist in pure theoretical calculations or the large time cost in actual experiments, and can relatively simply and quickly predict the heat transfer efficiency of the structure, providing a reference for the further optimization or practical application of the exhaust gas heat exchange structure. Moreover, by obtaining the heat transfer efficiency evaluation result of the designed exhaust gas heat exchange structure based on the operation results of the finite element analysis, the accurate and rapid evaluation of the heat transfer efficiency of the exhaust gas heat exchange structure can be realized, and thus the performance of the designed exhaust gas heat exchange structure can be accurately and quickly obtained. Brief Description of the Drawings

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0026] Figure 1 It is a schematic flowchart of a method for evaluating the heat transfer efficiency of an exhaust gas heat transfer structure provided in an embodiment of the present application;

[0027] Figure 2 It is a schematic three-dimensional model diagram of an ammonia-hydrogen engine exhaust gas heat transfer structure provided in an embodiment of the present application;

[0028] Figure 3 It is a schematic diagram of the exhaust gas flow region in the ammonia-hydrogen engine exhaust gas heat transfer structure provided in an embodiment of the present application;

[0029] Figure 4 It is a schematic diagram of the heated gas flow region in the ammonia-hydrogen engine exhaust gas heat transfer structure provided in an embodiment of the present application;

[0030] Figure 5 It is a schematic diagram of the central cylinder structure in the heated gas flow region of the ammonia-hydrogen engine exhaust gas heat transfer structure provided in an embodiment of the present application;

[0031] Figure 6 It is a mesh division diagram of the three-dimensional model of the ammonia-hydrogen engine exhaust gas heat transfer structure provided in an embodiment of the present application;

[0032] Figure 7 It is a temperature contour map in the heated gas flow region of the ammonia-hydrogen engine exhaust gas heat transfer structure under the simulated conditions provided in an embodiment of the present application;

[0033] Figure 8 It is a schematic structural diagram of a computer device provided in an embodiment of the present application.

[0034] Reference Numerals: 1 Exhaust Gas Inlet, 2 Exhaust Gas Outlet, 3 to 17 Correspond to Multiple Fluid Channels, 18 Line Channel, 19 Ammonia Inlet, 20 Ammonia Outlet, 21 Fluid Channel Outlet. Detailed Description of the Embodiments

[0035] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts shall fall within the protection scope of the present application.

[0036] To make the above objects, features, and advantages of the present application more obvious and understandable, the present application will be further described in detail below in conjunction with the drawings and specific embodiments.

[0037] In an exemplary embodiment, the present application provides a method for evaluating the heat transfer efficiency of an exhaust gas heat exchange structure, which is implemented using COMSOL multi-physics simulation software. Among them, a zero-dimensional reaction engineering module is added based on the COMSOL multi-physics simulation software to determine the kinetic parameters of each elementary reaction during the ammonia decomposition reaction (corresponding to step 100 below); determine the material properties of the catalytic channel and the internal fluid (corresponding to step 101 below); establish a three-dimensional structural model of the catalytic channel and construct a physical field (corresponding to steps 100-step 102 below); determine the boundary conditions and construct a control equation (corresponding to step 102 below); perform mesh division on the three-dimensional structure of the catalytic channel (corresponding to step 103 below); calculate and solve the control equation to obtain the substance distribution in the catalytic channel at different reaction times (corresponding to steps 104 and 105 below). Based on this, as Figure 1 shown, the method for evaluating the heat transfer efficiency of the exhaust gas heat exchange structure provided by the present application includes:

[0038] Step 100: Obtain the geometric parameters of the designed exhaust gas heat exchange structure, and establish a three-dimensional model of the designed exhaust gas heat exchange structure based on the geometric parameters to obtain a three-dimensional model in the first stage. Among them, the designed exhaust gas heat exchange structure includes an exhaust gas flow region, a heated gas flow region, and a heat transfer wall surface between the regions.

[0039] Step 101: Set the material properties of the designed exhaust gas heat exchange structure and the material properties of the internal fluid of the designed exhaust gas heat exchange structure in the three-dimensional model in the first stage to obtain a three-dimensional model in the second stage. Among them, the material properties of the designed exhaust gas heat exchange structure and the material properties of the internal fluid of the designed exhaust gas heat exchange structure include the thermal conductivity, constant pressure heat capacity, dynamic viscosity, and density of the fluids in the exhaust gas flow region and the heated gas flow region, as well as the material type, thermal conductivity, constant pressure heat capacity, and density of the heat transfer wall surface between the regions. The fluid type in the exhaust gas flow region is nitrogen. The fluid type in the heated gas flow region is ammonia.

[0040] Among them, in the heated gas flow area, the density of ammonia under standard conditions can be corrected according to the temperature of each position in the working environment. The corrected density of ammonia is expressed as:

[0041]

[0042] In the formula, is the density of the corrected ammonia. T is the temperature of each location in the working environment, in K, which will be updated in real time during the simulation.

[0043] Step 102: Setting and coupling the boundary conditions of the second-stage three-dimensional model based on the working environment parameters of the designed exhaust gas heat exchange structure to obtain a third-stage three-dimensional model, wherein the working environment parameters include the exhaust gas inlet flow rate and inlet temperature, and the heated gas inlet flow rate and inlet temperature.

[0044] Step 103: mesh the third-stage three-dimensional model to obtain mesh units.

[0045] Step 104: Perform finite element simulation analysis based on the grid cells to obtain operation results. For example, perform finite element simulation analysis based on the grid cells using a steady-state solver to obtain operation results.

[0046] Step 105: Obtain a heat exchange efficiency evaluation result of the designed exhaust gas heat exchange structure based on the operation result.

[0047] As a hydrogen-rich, zero-carbon energy carrier, ammonia has a higher volume energy density than hydrogen. It also has the characteristics of low transportation and storage costs and good safety. Therefore, ammonia has great potential as a new engine fuel. However, compared with traditional fossil fuels, ammonia has poor thermodynamic properties and has combustion problems such as high autoignition temperature, low flame speed, and narrow flammable limit. Therefore, it is necessary to improve the combustion characteristics of ammonia through suitable combustion aids. Hydrogen happens to have a higher laminar flame speed and a wider flammable limit. It is also a zero-carbon fuel, which makes up for the shortcomings of pure ammonia fuel.

[0048] In order to avoid the storage and transportation problems of hydrogen, it is generally preferred to directly provide the hydrogen required for combustion through the partial decomposition of pure ammonia fuel. One way is to make full use of the heat of the engine exhaust gas, and preheat the ammonia fuel in the ammonia-hydrogen engine without adding an external heat source to increase the ammonia decomposition conversion rate and provide sufficient hydrogen to support combustion. Based on this, in another exemplary embodiment of the present application, taking the use of the evaluation method provided above in the present application to implement the heat exchange efficiency evaluation of the exhaust heat exchange structure of the ammonia-hydrogen engine as an example, the specific implementation process and the effect achieved by the evaluation method provided in the present application are explained, including:

[0049] Step S1: Design the exhaust gas heat exchange structure of the ammonia-hydrogen engine, determine the geometric parameters of the exhaust gas heat exchange structure of the ammonia-hydrogen engine, and establish a three-dimensional model of the first stage of this exhaust gas heat exchange structure based on the COMSOL multi-physics simulation software.

[0050] For example, the exhaust gas heat exchange structure is as Figure 2 shown, consisting of an exhaust gas flow region ( Figure 3 ), a heated gas flow region ( Figure 4 ) and the heat transfer wall surface between the regions. As Figure 3 shown, the exhaust gas flow region is composed of two coaxial cylinders spliced together. Among them, the exhaust gas inlet section is a cylinder with a height of 0.22 m and a cross-sectional radius of 0.073 m. The main exhaust gas flow section is a cylinder with a height of 0.86 m and a cross-sectional radius of 0.2 m. The exhaust gas enters from one end of the cylinder with a smaller cross-section ( Figure 3 exhaust gas inlet 1) and flows out from one end of the cylinder with a larger cross-section ( Figure 3 exhaust gas outlet 2).

[0051] As Figure 4 shown, the heated gas flow region is relatively complex. The overall shape is a fin-like structure connected along the axis at eight angles on the wall surface of the central cylinder. This is because there is no fluid flow region inside the ordinary fin, while there is fluid flow inside this fin-like structure (corresponding to fluid channels 3 to 17), and it is the main heat exchange region.

[0052] As Figure 4 and Figure 5 shown, for the central cylinder, its cross-sectional radius can be set to 0.05 m and its height can be set to 0.78 m. The radius of ammonia inlet 19 can be set to 0.02 m, and the radius of ammonia outlet 20 can be set to 0.025 m. Figure 4 These fin-like structures in

[0053] Inside each fin-like structure, it is symmetrically separated by a partition to form two channels. The partition is not connected to one end, allowing the fluid to flow into the next channel. In this way, each fin-like structure is a structure that enables the heated fluid to flow back and forth along the axis for heat exchange. After the heated fluid flows back and forth once inside one fin-like structure, it enters the next fin-like structure through a small connecting channel between adjacent fin-like structures. Eight fin-like structures are evenly distributed in all directions around the circumference of the cylinder, forming 16 channels along the axis direction (i.e., fluid channels 3 to 17 and line channel 18). However, only the first 15 channels (fluid channels 3 to 17) in the order of the gas flow direction are available for fluid circulation. The last channel (line channel 18) is sealed around and does not allow fluid to flow. Its design concept itself is considered for use as an intermediate area for other equipment lines such as wires to connect into the central cylinder, reducing the contact between the lines and the gas and protecting the lines. For the purpose of simplifying the structure, the lines are not shown in the provided 3D model, and only the significance of the absence of fluid flow channels is explained.

[0054] In this embodiment, ammonia enters the fluid channel 3 from the ammonia inlet 19. There is an outlet (i.e., fluid channel outlet 21) at the end of the fluid channel 17 where it connects to the cylinder surface, allowing the almost heated ammonia to enter the central cylinder area and extend partially at the other end of the central cylinder, and then flow out of the entire tail gas heat exchange structure through the ammonia outlet 20. The central cylinder is designed for the heated fluid, which is the decomposition of ammonia here. In actual application, a catalytic bed will be filled in it for ammonia catalytic decomposition. Whether the catalytic bed exists has little effect on the heat exchange effect. Therefore, in order to simplify the model, the catalytic bed is not modeled. The above only explains the role of the central cylinder channel in actual application.

[0055] Step S2: Determine the material properties of the tail gas heat exchange structure and the internal fluid, and set the three-dimensional model in the first stage established in step S1 to obtain the three-dimensional model in the second stage. Among them, the provided material properties include the thermal conductivity, constant pressure heat capacity, dynamic viscosity, and density of the fluid in the tail gas flow area and the heated gas flow area, the material type of the heat transfer wall surface, thermal conductivity, constant pressure heat capacity, and density.

[0056] In this embodiment, the thermal conductivity, constant pressure heat capacity, dynamic viscosity, and density of nitrogen are greatly affected by temperature. Therefore, in the material library of the COMSOL multi-physics simulation software, these parameters will be calculated and adjusted in real time internally, without fixed specific values, and are all functions related to temperature and are invisible. The thermal conductivity, constant pressure heat capacity, and dynamic viscosity of ammonia are also functions related to temperature in the material library, but the function of ammonia density is not given. Therefore, the density of ammonia under standard conditions is selected and corrected according to temperature.

[0057] Further, in the actual application process, select SteelAISI4340 from the material library for the material type of the heat transfer wall surface. Its thermal conductivity, constant pressure heat capacity, and density are shown in Table 1.

[0058] Table 1 Material Properties of the Heat Transfer Wall Surface

[0059] Name Property Material Type Steel AISI 4340 Thermal Conductivity (W / (m·K)) 44.5 Specific Heat at Constant Pressure (J / (kg·K)) 475 <![CDATA[Density (kg / m 3 )]]> 7850

[0060] Step S3: Add the fluid heat transfer (ht) module and the turbulent k-ε (spf) module in the COMSOL multiphysics simulation software, and set the boundary conditions according to the actual working environment parameters of the tail gas heat exchange structure. In this embodiment, some parameters of the actual working environment are shown in Table 2.

[0061] Table 2 Partial Parameter Table of the Actual Working Environment

[0062] Name Property Nitrogen Inlet Flow Rate (kg / h) 1000 Nitrogen Inlet Temperature (K) 673.15 Ammonia Inlet Flow Rate (kg / h) 14 Ammonia Inlet Temperature (K) 293.15

[0063] At the same time, set the heat transfer wall surface in the fluid heat transfer (ht) module, add a thin layer boundary, set the shell type as non-multilayer shell, the thickness as 3 mm, the layer type as thermal thin approximation, and the remaining parameters as the material properties of the heat transfer wall surface in Table 1.

[0064] Step S4: Add the non-isothermal flow multiphysics module in the COMSOL multiphysics simulation software to couple the boundary conditions set in Step S3 to obtain the three-dimensional model of the third stage. Alternatively, the non-isothermal flow multiphysics module couples the fluid heat transfer (ht) module and the turbulent k-ε (spf) module in Step S3.

[0065] In this step, in the non-isothermal flow multiphysics settings, select the turbulent k-ε (spf) module for fluid flow, the fluid heat transfer (ht) module for heat transfer, select the Kays-Crawford for the heat transfer turbulence model, select "standard" for the thermal wall function, and include viscous dissipation during calculation.

[0066] Step S5: Perform reasonable mesh division on the three-dimensional structure model of the third stage established in Step S4 to obtain the finite element model. Among them, the mesh division result is as Figure 6 shown.

[0067] Step S6: Based on the finite element model, perform research settings. After the settings are completed, perform calculation and solution to obtain the operation results. Among them, use the steady-state solver for research settings, and finally solve and calculate to obtain the fluid temperature distribution in the structure at steady state. The operation results include: the outlet temperature of the heated gas, the constant pressure heat capacities of the heated gas and the tail gas at the inlet and outlet.

[0068] For example, after solving with a steady-state solver, the heat absorption situation of ammonia at steady state is obtained. The isothermal surface of the ammonia flow temperature in the heated gas flow domain is as Figure 7 shown. It can be clearly seen from Figure 7 that ammonia starts to absorb heat from the inlet, and the heat absorption process is relatively uniform. At the same time, the baffle plate greatly increases the gas flow travel and the heat transfer area, resulting in a better heating effect.

[0069] Step S7: Perform data processing and calculation on the operation result obtained through Step S6 to obtain the heat transfer efficiency of the tail gas heat exchange structure.

[0070] In this step, according to the operation result obtained in Step S6, the required parameters are derived, as shown in Table 3. To calculate the theoretical heat transfer amount, the theoretical outlet temperature T i1,NH3 of the heated fluid (ammonia) needs to be obtained. At this time, it satisfies that the theoretical outlet temperature T i1,NH3 of ammonia is equal to the theoretical outlet temperature T i1,N2 of nitrogen, that is, T i1,NH3 = T i1,N2 . Therefore, the theoretical outlet temperature T i1,NH3 of the heated fluid (ammonia) can be approximately obtained from the following equation:

[0071]

[0072] The left side of this equation for obtaining the theoretical outlet temperature of the heated fluid (ammonia) represents the theoretical heat absorption of ammonia, and the right side represents the theoretical heat absorption of nitrogen. Among them, M NH3 represents the mass flow rate of ammonia, M N2 represents the mass flow rate of nitrogen, T 0,NH3 represents the inlet temperature of ammonia, and T 0,N2 represents the inlet temperature of nitrogen. According to the data in Table 2 and Table 3, the theoretical outlet temperature T i1,NH3 of ammonia can be solved to be 662.52K.

[0073] Table 3 Parameter Table for Derivation Required for Heat Transfer Efficiency Calculation

[0074]

[0075] Then, according to the heat transfer efficiency calculation formula, the following derivation formula can be listed:

[0076]

[0077] In the formula, Q a represents the actual heat transfer amount, and Q t represents the theoretical maximum heat transfer amount.

[0078] In this embodiment, the heat transfer efficiency η of the tail gas heat exchange structure can be calculated through the above formula to be 86.71%, indicating that the heat transfer effect of this structure is good and it can make full use of the tail gas heat to preheat ammonia. Analyzing its structure, because the fin-like structure provides a large heat transfer area, and at the same time, the partition in the fin-like structure greatly increases the heat transfer travel of ammonia, which makes the heat transfer in the whole process more sufficient.

[0079] In summary, this application uses the COMSOL multi-physics simulation software to simulate and evaluate the heat transfer efficiency of the tail gas heat exchange structure of the ammonia-hydrogen engine. Without actual experiments, the approximate heat transfer efficiency of this structure is obtained simply and quickly, which proves the excellent heat transfer performance of this structure in the embodiment and provides a reference for the next structure optimization or application. It can be seen that this application can effectively reduce the R & D cost and improve the design reliability of the tail gas heat exchange structure through simulation evaluation, and can meet the actual application requirements through fewer engineering experiments.

[0080] In an exemplary embodiment, a computer device is provided. This computer device can be a server or a terminal, and its internal structure diagram can be as Figure 8 shown. This computer device includes a processor, a memory, an input / output interface (Input / Output, abbreviated as I / O), and a communication interface. Among them, the processor, the memory, and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. Among them, the processor of this computer device is used to provide computing and control capabilities. The memory of this computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of this computer device is used to store the heat transfer efficiency evaluation data of the tail gas heat exchange structure. The input / output interface of this computer device is used to exchange information between the processor and external devices. The communication interface of this computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, it implements a method for evaluating the heat transfer efficiency of a tail gas heat exchange structure.

[0081] Those skilled in the art can understand that Figure 8 the structure shown in

[0082] In an exemplary embodiment, a computer-readable storage medium is provided, storing a computer program, which, when executed by a processor, implements the steps in the above method embodiments.

[0083] In an exemplary embodiment, a computer program product is provided, including a computer program, which, when executed by a processor, implements the steps in the above method embodiments.

[0084] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use, and processing of relevant data need to comply with relevant regulations.

[0085] Those of ordinary skill in the art can understand that all or part of the processes in the above method embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the above method embodiments. Among them, any reference to a memory, database, or other medium used in the embodiments provided in this application can include at least one of non-volatile and volatile memories. Non-volatile memories can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memories can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0086] In each of the embodiments provided in the present application, the database involved may include at least one of a relational database and a non-relational database. The non-relational database may include a distributed database based on a blockchain, etc., without limitation. In each of the embodiments provided in the present application, the processor involved may be a general-purpose processor, a central processing unit, a graphics processing unit, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., without limitation.

[0087] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0088] Specific examples are used in this article to elaborate on the principle and implementation manner of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application; at the same time, for those of ordinary skill in the art, according to the idea of the present application, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present application.

Claims

1. A method for evaluating the heat exchange efficiency of an exhaust gas heat exchange structure, characterized in that, Including: Obtain the geometric parameters of the designed exhaust gas heat exchange structure, and establish a three-dimensional model of the designed exhaust gas heat exchange structure based on the geometric parameters to obtain the three-dimensional model in the first stage; Set the material properties of the designed exhaust gas heat exchange structure and the material properties of the fluid inside the designed exhaust gas heat exchange structure in the three-dimensional model in the first stage to obtain the three-dimensional model in the second stage; Set and couple the boundary conditions of the three-dimensional model in the second stage based on the working environment parameters of the designed exhaust gas heat exchange structure to obtain the three-dimensional model in the third stage; Perform mesh division on the three-dimensional model in the third stage to obtain mesh elements; Perform finite element simulation analysis based on the mesh elements to obtain the operation results; Obtain the heat transfer efficiency evaluation result of the designed exhaust gas heat exchange structure based on the operation results.

2. The heat transfer efficiency evaluation method of the exhaust gas heat exchange structure according to claim 1, characterized in that The heat transfer efficiency evaluation method of the exhaust gas heat exchange structure is implemented by using COMSOL multi-physics simulation software.

3. The heat exchange efficiency evaluation method of the tail gas heat exchange structure according to claim 1, characterized in that The designed exhaust gas heat exchange structure includes an exhaust gas flow region, a heated gas flow region, and a heat transfer wall surface between the regions.

4. The heat transfer efficiency evaluation method of the tail gas heat exchange structure according to claim 3, characterized in that The material properties include the thermal conductivity, constant pressure heat capacity, dynamic viscosity, and density of the fluids in the exhaust gas flow region and the heated gas flow region, as well as the material type, thermal conductivity, constant pressure heat capacity, and density of the heat transfer wall surface between the regions.

5. The heat transfer efficiency evaluation method of the exhaust gas heat exchange structure according to claim 3, characterized in that, The fluid type in the exhaust gas flow region is nitrogen; the fluid type in the heated gas flow region is ammonia.

6. The heat transfer efficiency evaluation method of the tail gas heat exchange structure according to claim 5, characterized in that, In the heated gas flow region, the density of ammonia under standard conditions is corrected according to the temperature at each position in the working environment.

7. The heat transfer efficiency evaluation method of the tail gas heat exchange structure according to claim 6, characterized in that The corrected density of ammonia is expressed as: In the formula, is the density of the corrected ammonia gas, and T is the temperature at each position in the working environment.

8. The heat exchange efficiency evaluation method of the exhaust gas heat exchange structure according to claim 1, characterized in that, Use a steady-state solver to perform finite element simulation analysis based on the mesh elements to obtain the operation results.

9. A computer device, comprising: A memory, a processor, and a computer program stored on the memory and executable on the processor, wherein the processor executes the computer program to implement the heat transfer efficiency evaluation method of the exhaust gas heat exchange structure according to any one of claims 1-7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the heat transfer efficiency evaluation method of the exhaust gas heat exchange structure according to any one of claims 1-7.

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