A method for optimizing the air volume of CDQ circulation using COMSOL Multiphysics software

Abstract

The present invention discloses a method for optimizing the dry quenching coke circulation air volume using COMSOL Multiphysics software, which belongs to the technical field of optimizing the dry quenching coke circulation air volume, and comprises the following steps: first, obtaining data through actual production measurement of the dry quenching furnace in a coking plant; then establishing a target dry quenching furnace model and establishing a simulation working condition; analyzing the flow field, temperature field and reaction field in the dry quenching furnace through software, and studying the distribution of pressure, temperature and chemical reaction in the dry quenching furnace under normal production. The present invention proposes a method for optimizing the dry quenching coke circulation air volume using COMSOL Multiphysics software, which combines data collected on-site with COMSOL Multiphysics software simulation to simulate the material flow, gas-solid convection heat transfer and gas-solid reaction in the dry quenching furnace, and investigates the distribution of its internal pressure field, temperature field and reaction field, and simultaneously studies the influence of different circulation air volumes on heat transfer and coke burnout in the dry quenching furnace, and proposes a circulation air volume optimization working condition suitable for the target dry quenching furnace.

Description

Technical Field

[0001] The present invention relates to the technical field of optimizing the air volume of a dry coke quenching cycle, and in particular to a method for optimizing the air volume of a dry coke quenching cycle by utilizing COMSOL Multiphysics software. Background Art

[0002] Coke dry quenching (CDQ) technology involves exchanging heat between hot coke and a nitrogen-based circulating gas. During the quenching process, the hot coke slowly enters the CDQ furnace from a coke tank car. Low-temperature circulating gas enters from the bottom of the CDQ furnace to exchange heat with the hot coke. The low-temperature coke is then discharged from the CDQ furnace. From the CDQ furnace outlet, the hot circulating gas enters a primary dust collector and then a waste heat boiler, where it exchanges heat with water in the boiler to generate high-temperature steam. This steam is then transported to a steam turbine power station for power generation. The cooled circulating gas passes through a secondary dust collector, a circulating fan, and a heat exchanger, where its temperature drops to approximately 160°C. It then reenters the CDQ furnace to exchange heat with the coke. This cycle continues until the coke cools to below 200°C.

[0003] COMSOL Multiphysics, a large-scale, advanced numerical simulation software based on the finite element method, simulates physical phenomena by solving partial differential equations or systems of partial differential equations. With continuous updates and development, the software has been applied to scientific research and engineering calculations in various fields, and is hailed by today's scientists as "the most professional multi-physics simulation and analysis software." COMSOL offers multiple specialized modules that can be combined with any number of physical fields, simulating various physical processes in science and engineering. It is currently widely used in leading global numerical simulation fields.

[0004] The CDQ furnace is the main structure of the CDQ system. The material flow, gas-solid convection heat transfer, and gas-solid reaction within it are key to studying the overall CDQ heat transfer efficiency and coke burnout, and are also key to determining the operating efficiency and economic benefits of the entire CDQ system. The logistics within the CDQ furnace are mainly divided into two streams: gas and solid: one is the downward movement of the solid material red coke under the action of gravity; the other is the movement of circulating gas from bottom to top through the coke layer under fan pressure. The interaction and energy transfer between these two logistics are the core of the CDQ furnace problem. Through on-site testing, a large number of CDQ furnace production and operation parameters can be obtained. Analyzing and calculating this data plays a huge role in understanding CDQ furnace problems. Summary of the Invention

[0005] The object of the present invention is to provide a method for optimizing the CDQ circulating air volume using COMSOL Multiphysics software. The software is used to simulate material flow, gas-solid convection heat transfer, and gas-solid reaction in a CDQ furnace, thereby optimizing the CDQ circulating air volume. This technology can meet the CDQ furnace coke discharge temperature requirements, evenly distribute the cooling section temperature, optimize the CDQ furnace cooling chamber coke quenching effect, and fully utilize the CDQ furnace processing capacity to solve the problems raised in the above-mentioned background technology.

[0006] To achieve the above object, the present invention provides the following technical solution: a method for optimizing the air volume of a CDQ cycle using COMSOL Multiphysics software, comprising the following steps:

[0007] S1: Taking the CDQ system in stable operation as the research object, the operating parameters of the CDQ system and the CDQ burnout rate were measured and analyzed, and the actual production data and CDQ furnace structure were obtained;

[0008] S2: Model assumptions;

[0009] S3: COMSOL Multiphysics was used to establish a geometric model for the computational domain of a 2D CDQ furnace model. The specific structures of the ramp and annular duct were ignored, and the pre-storage section and cooling section were primarily used. Nitrogen was used as the filling material. The cooling section and pre-storage section were classified as porous media domains, and coke was used as the filling material.

[0010] S4: Model meshing;

[0011] S5: Model verification: The accuracy of the CDQ furnace model is verified by comparing the field measured data with the CDQ furnace simulation results;

[0012] S6: Analyze the material flow, gas-solid convection heat transfer and gas-solid reaction in the CDQ furnace under different circulating air volumes.

[0013] Furthermore, for step S4, the computational domain is meshed using Meshing in COMSOL Multiphysics software;

[0014] The 2D CDQ furnace model is mainly divided into two parts: the cooling section and the pre-storage section. Both are porous media domains. Although the pre-storage section is a porous media domain, its structure is simple and it is not the main area for gas flow, heat exchange, and coke reaction. Therefore, its meshing can be appropriately coarsened.

[0015] The cooling section, which is also a porous media domain, is quite different. As the main area of gas flow and heat exchange in the CDQ furnace, chemical reactions also mainly occur there. Therefore, the mesh on it naturally needs to be refined. The number of meshes in the pre-existing porous media domain is appropriately reduced, the cooling section is refined, and the fluid inlet and outlet boundaries are reasonably refined.

[0016] Furthermore, for step S2, the CDQ furnace can be regarded as a packed bed reactor formed by the accumulation of coke blocks. The complex and chaotic micropores of the coke itself are ignored. The accumulated pores are used as the porosity of the porous medium, and the coke layer is regarded as a uniform porous medium. Its heat transfer and reaction problems are studied from a macroscopic perspective.

[0017] Therefore, the following assumptions are made:

[0018] The coke in the CDQ furnace is a uniform porous medium with isotropy;

[0019] Ignore the pores of the coke itself, focus on the accumulated pores of the coke, and regard it as a whole;

[0020] The temperature of the coke itself is uniform, and its high-temperature deformation can be ignored;

[0021] Heat transfer is mainly gas-solid convection heat transfer, including chemical reaction heat, ignoring radiation heat transfer, and all external walls are treated as thermal insulation walls;

[0022] Ignore the periodic charging of the CDQ furnace and only calculate the heat transfer and coke burning reaction within one cycle;

[0023] The operating parameters of the CDQ furnace are constant and without fluctuation.

[0024] Furthermore, for step S5, the accuracy of the CDQ furnace model is verified by comparing the field measured data with the CDQ furnace simulation results. The comparison data include the coke discharge temperature, outlet gas temperature, pre-chamber lower section pressure, and outlet CO and CO2 concentrations.

[0025] Furthermore, for step S6, the flow field, temperature field, and reaction field of the CDQ furnace of the calculation results are analyzed to study the distribution of pressure, temperature, and chemical reaction in the CDQ furnace under normal production. The pressure distribution in the CDQ furnace is high in the middle and low on both sides, and the upper part of the cooling chamber and the pre-storage chamber are in a slightly negative pressure state.

[0026] The airflow velocity in the CDQ furnace is higher at the CDQ furnace entrance and the chute entrance, and is more uniform in the cooling chamber. The airflow velocity in the middle of the cooling chamber is slightly lower than that in the periphery, and more airflow diffuses upward from the periphery of the CDQ furnace into the chute;

[0027] The temperature inside the CDQ furnace is high in the middle and low around the edges. The lower section of the cooling chamber is close to the inlet air temperature, while the upper section is very high with a clear temperature boundary.

[0028] The combustion reaction of coke occurs in the lower section of the cooling chamber where the temperature is lower, while the water-gas reaction and dissolution reaction of coke occur in the upper section of the cooling chamber where the temperature is higher. The coke reaction in the cooling chamber continuously produces CO, and the change in its concentration can reflect the coke burning loss in the cooling chamber.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The present invention proposes a method for optimizing the CDQ circulating air volume using COMSOL Multiphysics software. By combining field-collected data with COMSOL Multiphysics simulations, the method simulates material flow, gas-solid convection heat transfer, and gas-solid reaction within the CDQ furnace, investigates the distribution of the internal pressure field, temperature field, and reaction field, and simultaneously studies the effects of different circulating air volumes on heat transfer and coke burnout within the CDQ furnace. This method thus proposes an operating range for the optimized circulating air volume, which meets the coke discharge temperature requirements and ensures uniform temperature distribution in the cooling section, fully utilizing the CDQ furnace's processing capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The CDQ furnace mesh model is obtained by meshing the computational domain using the COMSOL Multiphysics software of the present invention;

[0032] Figure 2 A temperature and height relationship diagram of the central axis position of the CDQ furnace of the present invention;

[0033] Figure 3 This is a graph showing the relationship between CO concentration and height at the central axis of the CDQ furnace of the present invention. DETAILED DESCRIPTION

[0034] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only 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 making creative efforts are within the scope of protection of the present invention.

[0035] A method for optimizing CDQ cycle air volume using COMSOL Multiphysics software to record nitrogen material and coke material properties;

[0036] See the table below for nitrogen material properties:

[0037]

[0038] The coke material properties are shown in the table below:

[0039]

[0040] The coke material properties are shown in the table below:

[0041]

[0042] The computational domain was meshed using the Meshing function in COMSOL Multiphysics. The 2D CDQ furnace model is mainly divided into a cooling section and a pre-storage section. Both are porous media domains. Although the pre-storage section is large, its structure is simple and it is not the main area for gas flow, heat exchange, and coke reaction. Therefore, its meshing can be appropriately coarsened.

[0043] The cooling section, which is also a porous media domain, is quite different. As the main area of gas flow and heat exchange in the CDQ furnace, chemical reactions also mainly occur there. Therefore, the mesh on it naturally needs to be refined. The number of meshes in the pre-existing porous media domain is appropriately reduced, the cooling section is refined, and the fluid inlet and outlet boundaries are reasonably refined.

[0044] Figure 1 The complete mesh includes 5296 domain elements and 316 boundary elements.

[0045] Example 1:

[0046] COMSOL Multiphysics software simulates material flow, gas-solid convective heat transfer, and gas-solid reaction in the CDQ furnace to optimize the CDQ circulating air volume. The specific implementation method is as follows:

[0047] Step 1: Collection of target CDQ furnace data

[0048] On-site data testing and collection were conducted on a CDQ furnace undergoing stable operation. The tests included surface temperature, internal temperature and pressure at various points, gas composition at different depths and locations, and changes in gas composition at the CDQ furnace inlet and outlet under different operating conditions. The company also collected data on various operating parameters of the CDQ furnace and various coke properties.

[0049] Step 2: Selection of process parameters

[0050] Operating parameters of a 140t / h CDQ furnace in a coking plant

[0051]

[0052] 140t / h CDQ furnace inlet gas composition

[0053]

[0054] The control equation is established:

[0055] The mathematical model of the CDQ furnace includes gas flow, convective heat transfer, and coke reaction. The mathematical model of the CDQ furnace uses COMSOL Multiphysics to implement free and porous media flow, local non-thermal equilibrium heat transfer in porous media, and porous media reaction flow coupled by the Brinkman equation and concentrated species transport.

[0056] (1) Fluid motion equation:

[0057] In the free and porous media flow fields, the fluid flow in the CDQ furnace is divided into two domains: one domain is the slow motion of the fluid in the porous media domain controlled by the Brinkman equation;

[0058] The other domain is the fast free flow in the fluid domain described by the Navier-Stokes equations;

[0059] Brinkman equation:

[0060] The dependent variables in the Brinkman equation are the Darcy velocity and pressure. Flow in porous media is governed by a combination of the continuity equation and the momentum equation, which together form the Brinkman equation:

[0061] (a) Continuity equation

[0062] (b) Momentum equation

[0063] μ is the dynamic viscosity of the fluid (kg / (m·s)), u is the velocity vector (m / s), ρ is the density of the fluid (kg / m3), P is the pressure (Pa), ε p is the porosity, κ is the permeability tensor of the porous medium (m 2 ), Q br is the mass source (kg / (m 3 ·s)), F is gravity or other body force (kg / (m 2 ·s 2 )), It is disabled when the Ignore inertial terms (Stokes-Brinkman) check box is selected. For flows with variable density, the above two formulas are solved together with the equation of state relating density to temperature and pressure. For incompressible flows, the density remains constant within any fluid particle. The equations apply to incompressible as well as compressible flows with varying density and viscosity.

[0064] Navier-Stokes equations:

[0065] (a) Continuity equation

[0066] (b) Momentum equation

[0067] (2) Energy transfer equation

[0068] Local thermal nonequilibrium heat transfer is used when the porous matrix and the fluid are not in temperature equilibrium and is governed by a set of two equations;

[0069]

[0070]

[0071]

[0072] θ p is the solid volume fraction, ρ s , ρ f is the density of solids and fluids (kg / m 3 ), C p,s 、C p,f is the heat capacity of the solid and fluid at constant pressure (J / (kg·K)), q s ,q f is the conductive heat flux of solid and fluid (W / m 2 ), k s 、k f is the thermal conductivity of the solid and fluid (W / (m·K)), q sf is the gap convection coefficient (W / (m 3 ·K)), Q s , Q f It is a solid and fluid heat source.

[0073] (3) Chemical and mass transfer equations:

[0074] ①Chemical reaction rate, enthalpy and entropy equations

[0075] The coke burning reaction in the CDQ furnace, namely C+CO2=2CO and C+H2O=H2+CO, is an irreversible reaction, and its reaction rate equation is:

[0076] Enthalpy equation: H j =∑ i∈prod v ij h i -∑ i∈react (-v ij )h i

[0077] Entropy equation: S j =∑ i∈prod v ij s i -∑ i∈react (-v ij )s i

[0078] ②Material transfer equation

[0079]

[0080]

[0081]

[0082] In the equation: ρ is the density of the mixture (kg / m 3 ), u is the mass average velocity of the mixture (m / s), is the average diffusion coefficient of the mixture (m 2 ·s),ω i is the mass fraction, j i is the mass flux relative to the mass average velocity (kg / (m 2 ·s)), R i is an expression describing the rate of production or consumption (kg / (m 3 ·s)), is the thermal diffusivity (kg / (m·s)), D ik is the Maxwell diffusion coefficient (m 2 ·s).

[0083] Parameters and boundary conditions:

[0084] During a CDQ cycle, the coke can be considered relatively stationary. The circulating gas passes through the coke pores from bottom to top, exchanging heat with the coke and causing a burn reaction. The correct boundary conditions are crucial for obtaining accurate results using numerical simulations of CDQ furnaces.

[0085] The CDQ system's operating conditions often fluctuate due to the influence of the coke oven, power generation, and its own factors. The test content included changes in surface temperature, internal temperature, internal pressure, gas composition at different depths and locations, and gas composition at the CDQ inlet and outlet under different operating conditions. At the same time, various operating parameters of the plant's CDQ furnace and various properties of the coke were collected. A model was developed based on the actual size of the CDQ furnace. The required boundary conditions included inlet gas flow rate, inlet gas composition, inlet gas velocity, inlet gas temperature, initial temperature, coke carbon content, and outlet pressure.

[0086] a. Set the initial temperature of the porous medium domain to 1400K and the inlet temperature to 430K;

[0087] b. Set the initial speed in the furnace to 2.2m / s;

[0088] c. Set the CDQ furnace inlet to mass flow;

[0089] d. Set the initial carbon concentration to 59000 mol / m 3 , gas composition is molar concentration;

[0090] e. Set the porosity of the coke layer to 0.56

[0091] Step 3: Model Verification

[0092] The simulation results were compared with actual test results. The comparison data included coke discharge temperature, outlet gas temperature, lower pre-chamber pressure, and outlet CO and CO2 concentrations. The coke discharge temperature and outlet gas temperature effectively verified the accuracy of the heat transfer results, while the lower pre-chamber pressure verified the accuracy of the flow field results. The coke reactivity within the CDQ furnace was determined by the outlet CO and CO2 concentrations.

[0093]

[0094] The error between the model's simulated data and measured data is less than 10%, which shows good reliability and accuracy;

[0095] Step 4: Influence of circulating air volume on the temperature field in the CDQ furnace

[0096] Select different circulation air volume conditions

[0097]

[0098] In order to compare the temperature variation with the CDQ furnace height under different circulating air volumes, the temperature and height relationship diagram was drawn at the center axis position of the CDQ furnace.

[0099] See also Figure 2 At the same height, as the circulating air volume increases, the temperature inside the CDQ furnace decreases, and the temperature at the CDQ furnace entrance also increases due to the decrease in circulating air volume. 3 / h, the temperature at the CDQ furnace entrance has reached 546K, and its coke discharge temperature is much higher than the design value. The heat exchange effect of the CDQ furnace cooling chamber can no longer meet the coke quenching requirements; when the circulating air volume reaches 170000m 3 / h, although the coke discharge temperature meets the design requirements, the temperature in the lower and middle sections of the CDQ furnace cooling chamber is very low, which indicates that the heat exchange capacity of the CDQ furnace cooling chamber is excessive. Although the excessive circulating air volume has a very good quenching effect, it has a great impact on the inclined channel and the annular air duct, affecting their service life. In addition, it also increases the burden on the subsequent sections of the CDQ furnace, and the operating pressure of the entire CDQ system increases. When the circulating air volume is 150000m 3 / h and 160000m 3 / h, the coke discharge temperature of the CDQ furnace meets the requirements and the temperature distribution in the cooling section is relatively uniform, which indicates that the coke quenching effect of the CDQ furnace cooling chamber is good and its processing capacity is fully utilized. 3 / h, the CDQ furnace has a better coke quenching effect.

[0100] See also Figure 3 As the circulating air volume increases, the CO concentration continues to rise, that is, the coke loss in the CDQ furnace increases with the increase in circulating air volume, which is consistent with the actual test calculation results. From the figure, we can see that as the circulating air volume increases, the corresponding CO concentration line rises significantly overall, indicating that the increase in circulating air volume causes the increase in coke loss, and the increase in circulating air volume brings in more O2, CO2, and H2O to participate in the reaction.

[0101] Effect of circulating air volume on temperature field in CDQ furnace

[0102] The temperature in the CDQ furnace gradually rises from bottom to top, and the temperature in the furnace still shows a concave boundary in the upper part of the cooling section, but the temperature value in the furnace is different. As the circulating air volume increases, the temperature in the cooling section gradually decreases, and the coke cooling effect becomes better and better. For low circulating air volume, although the decrease in the velocity of the gas entering the furnace is conducive to the contact and sufficient heat exchange between the circulating gas and the coke, the insufficient air volume cannot take away enough heat, so the overall temperature of the cooling section in the furnace is relatively high; for high circulating air volume, sufficient circulating gas takes away a lot of heat, and the overall temperature of the cooling section in the CDQ furnace is very low, and the coke removal effect is also very good, but due to the high gas velocity, the heat exchange efficiency of the circulating gas is relatively low, and the overall outlet temperature of the circulating gas is lower than the outlet temperature of the low circulating air volume, which increases the working pressure of the boiler, dust removal and fan in the subsequent process.

[0103] Effect of Circulating Air Volume on Coke Reaction Field in CDQ Furnace

[0104] Circulating air volume, one of the most critical operating conditions of a CDQ system, plays a crucial role in ensuring the stable operation of the entire system. Similarly, it inevitably has a significant impact on coke loss within the CDQ furnace. As the circulating air volume increases, CO concentration rises, meaning that coke loss within the CDQ furnace increases with increasing circulating air volume. To minimize coke loss, the circulating air volume should be appropriately reduced. At the same time, considering the requirements for quenching, the circulating air volume should be kept at a moderate level.

[0105] In summary, the method of optimizing the CDQ circulating air volume using COMSOL Multiphysics software of the present invention combines data collected on-site with COMSOL Multiphysics software simulation to simulate the material flow, gas-solid convection heat transfer, and gas-solid reaction in the CDQ furnace, and investigates the distribution of the internal pressure field, temperature field, and reaction field. At the same time, the effects of different circulating air volumes on heat transfer and coke burnout in the CDQ furnace are studied, and a circulating air volume optimization operating condition suitable for the target CDQ furnace is proposed.

[0106] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A method for optimizing the air volume of a CDQ cycle using COMSOL Multiphysics software, characterized in that: The following steps are involved: S1: Taking the CDQ system in stable operation as the research object, the operating parameters of the CDQ system and the CDQ burnout rate were measured and analyzed, and the actual production data and CDQ furnace structure were obtained; S2: Model assumption: The CDQ furnace can be regarded as a packed bed reactor formed by the accumulation of coke blocks. The complex and chaotic micropores of the coke itself are ignored. The accumulated pores are used as the porosity of the porous medium. The coke layer is regarded as a uniform porous medium. Its heat transfer and reaction problems are studied from a macroscopic perspective. Therefore, the following assumptions are made: (1) The coke in the CDQ furnace is a uniform porous medium with isotropy; (2) Ignore the pores of the coke itself and focus on the accumulated pores of the coke, treating it as a whole; (3) The temperature of the coke itself is uniform, and its high-temperature deformation is ignored; (4) Heat transfer is mainly gas-solid convection heat transfer, including chemical reaction heat, ignoring radiation heat transfer, and the external wall surface is treated as an adiabatic wall surface; (5) Ignore the periodic charging of the CDQ furnace and only calculate the heat transfer and coke burning reaction within one cycle; (6) All operating parameters of the CDQ furnace are constant and without fluctuation; S3: COMSOL Multiphysics was used to establish a geometric model for the computational domain of a 2D CDQ furnace model. The specific structures of the ramp and annular duct were ignored, and the pre-storage section and cooling section were primarily used. Nitrogen was used as the filling material. The cooling section and pre-storage section were classified as porous media domains, and coke was used as the filling material. S4: Model meshing; S5: Model Verification: The accuracy of the CDQ furnace model is verified by comparing the field measured data with the CDQ furnace simulation results. The comparison data includes the coke discharge temperature, outlet gas temperature, the lower section pressure of the pre-storage chamber, and the outlet CO and CO2 concentrations. S6: Analyze the material flow, gas-solid convection heat transfer, and gas-solid reaction in the CDQ furnace under different circulating air volumes. Analyze the calculated flow, temperature, and reaction fields in the CDQ furnace. Study the distribution of pressure, temperature, and chemical reactions in the CDQ furnace under normal production. The pressure distribution in the CDQ furnace is high in the middle and low on both sides. The upper part of the cooling chamber and the pre-storage chamber are in a slightly negative pressure state. The airflow velocity in the CDQ furnace is higher at the CDQ furnace entrance and the chute entrance, and is more uniform in the cooling chamber. The airflow velocity in the middle of the cooling chamber is slightly lower than that in the periphery, and more airflow diffuses upward from the periphery of the CDQ furnace into the chute; The temperature inside the CDQ furnace is high in the middle and low around the edges. The lower section of the cooling chamber is close to the inlet air temperature, while the upper section is very high with a clear temperature boundary. The combustion reaction of coke occurs in the lower section of the cooling chamber where the temperature is lower, while the water-gas reaction and dissolution reaction of coke occur in the upper section of the cooling chamber where the temperature is higher. The coke reaction in the cooling chamber continuously produces CO, and the change in its concentration can reflect the coke burning loss in the cooling chamber.

2. The method for optimizing the CDQ cycle air volume using COMSOL Multiphysics software according to claim 1, wherein: For step S4, mesh the computational domain using Meshing in COMSOL Multiphysics software; The 2D CDQ furnace model is mainly divided into two parts: the cooling section and the pre-storage section. Both are porous media domains. Although the pre-storage section is a porous media domain, its structure is simple and it is not the main area for gas flow, heat exchange, and coke reaction. Therefore, its meshing can be appropriately coarsened. The cooling section, which is also a porous media domain, is quite different. As the main area of gas flow and heat exchange in the CDQ furnace, chemical reactions also mainly occur there. Therefore, the mesh on it naturally needs to be refined. The number of meshes in the pre-existing porous media domain is appropriately reduced, the cooling section is refined, and the fluid inlet and outlet boundaries are reasonably refined.

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