Pressure drop prediction method of layered porous structure along heat source direction

Abstract

The invention belongs to the technical field of porous structure heat exchangers, and provides a pressure drop prediction method for a layered porous structure along a heat source direction, which comprises the following steps: respectively establishing physical models of single-porosity porous structures of different specifications, respectively calculating the pressure drop of each single-porosity porous structure at different inlet fluid velocities, and calculating the pressure drop of each single-porosity porous structure at different inlet fluid velocities; establishing a model between the inlet fluid velocity and the pressure drop of the single-porosity porous structure; a layered porous structure model is constructed, the total flow of inlet fluid is confirmed, and the actual flow of each layer of single-porosity porous structure in the layered porous structure model is confirmed; the actual inlet fluid speed and the actual pressure drop of each layer of single-porosity porous structure are obtained; and averaging the actual pressure drop of each layer of single-porosity porous structure to obtain the pressure drop of the layered gradient porous structure along the heat source direction. According to the method, the actual flow and the actual speed of each single-porosity porous structure are comprehensively considered, the experiment and simulation cost is greatly reduced, and the prediction speed is increased.

Description

Technical Field

[0001] The invention belongs to the technical field of porous structure heat exchangers, and specifically discloses a method for predicting the pressure drop of a layered porous structure along a heat source direction. Background Art

[0002] As a new type of compact heat exchanger, porous structure heat exchanger has shown great application potential in thermal management systems of aircraft, high-speed ships and high-speed trains due to its unique structure and excellent heat transfer performance. However, porous structure heat exchangers face an urgent problem in practical applications, namely, large pressure drop, which seriously limits the widespread application of porous structure heat exchangers. In the design and optimization process of porous structure heat exchangers, pressure drop is one of the key factors affecting its performance. Excessive pressure drop will not only increase the energy consumption of the system, but also reduce the heat transfer efficiency, thereby weakening the advantages of heat exchangers in thermal management systems. In order to reduce the pressure drop while maintaining the efficient heat transfer performance of the heat exchanger, it has been proven to be an effective method to change the arrangement of the porous structure along the heat source direction while ensuring that the overall porosity remains unchanged. This arrangement can improve the fluid flow characteristics, thereby reducing the pressure drop and improving the overall heat transfer performance.

[0003] However, there are still obvious deficiencies in the prediction of pressure drop of layered gradient porous structures arranged along the direction of the heat source. The existing pressure drop prediction methods mainly rely on simulation or experimental means. Although the simulation method can simulate the fluid flow and pressure drop characteristics of the porous structure to a certain extent, its accuracy and reliability are limited by many factors such as model assumptions, calculation accuracy and boundary conditions; while the experimental method requires a lot of experimental equipment, time and manpower investment, and the universality of the experimental results is limited, and it is difficult to directly apply it to the design of heat exchangers with different working conditions and structures. Therefore, whether it is through simulation or experimental means to obtain the pressure drop data of non-uniform structures, it takes a lot of time and money, which undoubtedly increases the difficulty of research and development and optimization of porous structure heat exchangers, and limits its wide application in actual engineering.

[0004] In summary, the prior art lacks an effective and efficient method for predicting the pressure drop of a layered porous structure arranged along the direction of the heat source. The lack of such a prediction method makes it difficult to quickly and accurately evaluate the pressure drop performance of different structural arrangement schemes during the design and optimization of porous structure heat exchangers, which in turn affects the performance optimization and promotion of the heat exchanger. Therefore, the development of a method that can quickly and accurately predict the pressure drop of a layered porous structure arranged along the direction of the heat source is of great practical significance for promoting the widespread application of porous structure heat exchangers in thermal management systems of devices such as aircraft, high-speed ships and high-speed trains. Summary of the invention

[0005] In order to solve the problems in existing prediction of pressure drop of layered porous structures, such as complex prediction methods, high costs and inability to make rapid and accurate predictions, the present invention proposes a method for predicting the pressure drop of a layered porous structure along a heat source direction.

[0006] The present invention provides a method for predicting the pressure drop of a layered porous structure along a heat source direction, comprising the following steps: S1. Establishing physical models of single porosity porous structures of different specifications, respectively, calculating the pressure drop of each single porosity porous structure at different inlet fluid velocities, and establishing a model between the inlet fluid velocity and the pressure drop of the single porosity porous structure; S2. constructing a hierarchical porous structure model, confirming the total flow rate of the inlet fluid flowing into the hierarchical porous structure model, and confirming the actual flow rate of each layer of the single porosity porous structure in the hierarchical porous structure model; S3. Obtaining the actual inlet fluid velocity of each layer of the single porosity porous structure according to the actual flow rate of each layer of the single porosity porous structure obtained in step S2, and obtaining the actual pressure drop of each layer of the single porosity porous structure in the layered porous structure model according to the model between the inlet fluid velocity and the pressure drop of the single porosity porous structure obtained in step S1; S4. Taking an average of the actual pressure drops of the single-porosity porous structures of each layer obtained in step S3, the pressure drop of the layered gradient porous structure along the heat source direction is obtained.

[0007] According to a method for predicting a pressure drop of a layered porous structure along a heat source direction in some embodiments of the present application, in step S1, the single porosity porous structure is selected from one of a Weaire-Phelan lattice structure, a Kelvin lattice structure and a BCC lattice structure.

[0008] According to a method for predicting a pressure drop of a layered porous structure along a heat source direction in some embodiments of the present application, in step S1, the porosity range of the single porosity porous structure is: 0.7~0.95.

[0009] According to a method for predicting the pressure drop of a layered porous structure along a heat source direction in some embodiments of the present application, in step S1, the model between the inlet fluid velocity and the pressure drop of the single porosity porous structure is as shown in formula (1): (1) in, is the pressure drop per unit length, is the inlet fluid velocity, represents a linear constant, Represents a quadratic constant.

[0010] According to a method for predicting the pressure drop of a layered porous structure along a heat source direction in some embodiments of the present application, in step S2, the layered porous structure model is formed by stacking single-porosity porous structures of different porosities along the heat source direction, and the connecting rods of two layers of single-porosity porous structures are stepped transitions or smooth transitions.

[0011] According to a method for predicting a pressure drop of a hierarchical porous structure along a heat source direction in some embodiments of the present application, in step S2, the total flow rate of the inlet fluid flowing into the hierarchical porous structure model is as shown in formula (2): (2) in, represents the total inlet fluid flow rate of the layered porous structure model, represents the fluid density, is the inlet fluid velocity, Indicates the fluid inlet cross-sectional area.

[0012] According to a method for predicting the pressure drop of a layered porous structure along a heat source direction in some embodiments of the present application, in step S2, the actual flow rate of each layer of a single porosity porous structure in the layered porous structure model is as shown in formula (3) and formula (4): (3) (4) in, represents the total inlet fluid flow rate of the layered porous structure model, represents the actual flow rate entering the first layer of the single porosity porous structure, represents the actual flow rate entering the second layer of the single porosity porous structure, represents the pressure drop of the first layer of a single porosity porous structure, Represents the pressure drop of the second layer of single porosity porous structure.

[0013] According to a method for predicting a pressure drop of a layered porous structure along a heat source direction in some embodiments of the present application, in step S3, the actual inlet fluid velocity of each layer of the single porosity porous structure obtained in step S2 is obtained as shown in formulas (5) and (6): (5) (6) in, represents the actual inlet fluid velocity of the first layer of a single porosity porous structure, represents the actual flow rate entering the first layer of the single porosity porous structure, represents the total inlet fluid flow rate of the layered porous structure model, is the inlet fluid velocity, represents the actual inlet fluid velocity of the second layer of the single porosity porous structure, Represents the actual flow rate entering the second layer of single porosity porous structure.

[0014] According to a method for predicting a pressure drop of a layered porous structure along a heat source direction in some embodiments of the present application, in step S3, the pressure drop of each layer of a single porosity porous structure in the layered porous structure model is obtained as shown in formula (7) and formula (8): (7) (8) in, represents the actual pressure drop of the first layer of a single porosity porous structure, The linear constant representing the first layer of the single porosity porous structure, represents the actual inlet fluid velocity of the first layer of a single porosity porous structure, The quadratic constant representing the first layer of single porosity porous structure, represents the actual pressure drop of the second layer of the single porosity porous structure, The linear constant representing the second layer single porosity porous structure, represents the actual inlet fluid velocity of the second layer of the single porosity porous structure, Represents the quadratic constant of the second layer single porosity porous structure.

[0015] According to a method for predicting a pressure drop of a layered porous structure along a heat source direction in some embodiments of the present application, in step S4, the pressure drop of the layered gradient porous structure along the heat source direction is as shown in formula (9): (9) in, represents the pressure drop of the layered gradient porous structure along the heat source direction, represents the actual pressure drop of the first layer of a single porosity porous structure, It represents the actual pressure drop of the second layer single porosity porous structure.

[0016] The present invention proposes a method for predicting the pressure drop of a layered porous structure along the direction of a heat source. Based on the pressure drop of a porous structure with a uniform single porosity, the method can quickly and accurately predict the pressure drop of a layered porous structure arranged along the direction of a heat source in a variety of gradient ranges. The method does not require simulation means and experimental means, which greatly reduces the experimental and simulation costs. The method can also quickly and effectively determine the actual flow rate of each layer of the layered porous structure based on the pressure drop of the porous structure with a single porosity, and then determine the actual inlet fluid velocity of each layer of the layered porous structure, providing a basis for research that needs to be based on this parameter. The data obtained by the prediction method of the present invention is in good agreement with the simulation data, with a maximum error of less than 2.5%, and can be widely used in the design of engineering porous structure flow devices, such as the design of porous media heat exchangers and porous media purifiers. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic flow chart of a method for predicting pressure drop of a layered porous structure along a heat source direction according to the present invention; Figure 2 This is a schematic diagram of the structure of the layered porous structure model in Example 1 of the present invention; Figure 3 is the actual flow rate of each layer of the porous structure with a single porosity in Example 2 of the present invention; Figure 4 is the actual inlet fluid velocity of each layer of the single porosity porous structure in Example 2 of the present invention; Figure 5 This is a comparison diagram of the predicted pressure drop and the actual simulated pressure drop in Example 2 of the present invention; Figure 6 This is a comparison diagram of the predicted pressure drop and the actual simulated pressure drop in Example 3 of the present invention; Figure 7 This is a comparison diagram of the predicted pressure drop and the actual simulated pressure drop in Example 4 of the present invention; Figure 8 This is a comparison chart of the predicted pressure drop and the actual simulated pressure drop in Example 5 of the present invention. DETAILED DESCRIPTION

[0018] The following embodiments of the present invention are described in further detail in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0019] Example 1: This example provides a method for predicting the pressure drop of a layered porous structure along the direction of a heat source. Figure 1 As shown, the following steps are included: S1. Establishing physical models of single porosity porous structures of different specifications, respectively, calculating the pressure drop of each single porosity porous structure at different inlet fluid velocities, and establishing a model between the inlet fluid velocity and the pressure drop of the single porosity porous structure; As a preferred embodiment of the present invention, specifically, the pressure drop of each single porosity porous structure at different inlet fluid velocities can be obtained by experiments, simulations, literature data or theoretical formulas, and the single porosity porous structure is selected from one of a Weaire-Phelan lattice structure, a Kelvin lattice structure and a BCC lattice structure; the porosity range of the single porosity porous structure is: 0.7~0.95; the correlation between the inlet fluid velocity and the pressure drop of the single porosity porous structure can be fitted to a quadratic function curve with a constant term of 0, as shown in formula (1): (1) in, is the pressure drop per unit length, is the inlet fluid velocity, represents a linear constant, It represents the quadratic constant. Different single porosity porous structures correspond to different a and b, which can be obtained according to the actual fitting curve.

[0020] S2. constructing a hierarchical porous structure model, confirming the total flow rate of the inlet fluid flowing into the hierarchical porous structure model, and confirming the actual flow rate of each layer of the single porosity porous structure in the hierarchical porous structure model; As a preferred embodiment of this embodiment, specifically, Figure 2 As shown, the layered porous structure model is formed by stacking single-porosity porous structures with different porosities along the direction of the heat source, and the connecting rods of two layers of single-porosity porous structures are stepped transition or smooth transition; The total flow rate of the inlet fluid flowing into the hierarchical porous structure model is shown in formula (2): (2) in, represents the total inlet fluid flow rate of the layered porous structure model, represents the fluid density, is the inlet fluid velocity, Indicates the fluid inlet cross-sectional area; The actual flow rate of each layer of the single porosity porous structure in the hierarchical porous structure model is shown in formula (3) and formula (4): (3) (4) in, represents the total inlet fluid flow rate of the layered porous structure model, represents the actual flow rate entering the first layer of the single porosity porous structure, represents the actual flow rate entering the second layer of the single porosity porous structure, represents the pressure drop of the first layer of a single porosity porous structure, Represents the pressure drop of the second layer of single porosity porous structure.

[0021] S3. Obtaining the actual inlet fluid velocity of each layer of the single porosity porous structure according to the actual flow rate of each layer of the single porosity porous structure obtained in step S2, and obtaining the actual pressure drop of each layer of the single porosity porous structure in the layered porous structure model according to the model between the inlet fluid velocity and the pressure drop of the single porosity porous structure obtained in step S1; As a preferred embodiment of this invention, specifically, the actual inlet fluid velocity of each layer of the single porosity porous structure obtained according to the actual flow rate of each layer of the single porosity porous structure obtained in step S2 is as shown in formulas (5) and (6): (5) (6) in, represents the actual inlet fluid velocity of the first layer of a single porosity porous structure, represents the actual flow rate entering the first layer of the single porosity porous structure, represents the total inlet fluid flow rate of the layered porous structure model, is the inlet fluid velocity, represents the actual inlet fluid velocity of the second layer of the single porosity porous structure, represents the actual flow rate entering the second layer of the single porosity porous structure; The pressure drop of each layer of the single porosity porous structure in the layered porous structure model is shown in formula (7) and formula (8): (7) (8) in, represents the actual pressure drop of the first layer of a single porosity porous structure, The linear constant representing the first layer of the single porosity porous structure, represents the actual inlet fluid velocity of the first layer of a single porosity porous structure, The quadratic constant representing the first layer of single porosity porous structure, represents the actual pressure drop of the second layer of the single porosity porous structure, The linear constant representing the second layer single porosity porous structure, represents the actual inlet fluid velocity of the second layer of the single porosity porous structure, Represents the quadratic constant of the second layer single porosity porous structure.

[0022] S4. taking the average of the actual pressure drops of the single porosity porous structures of each layer obtained in step S3 to obtain the pressure drop of the layered gradient porous structure along the heat source direction; As a preferred embodiment of this embodiment, specifically, the pressure drop of the layered gradient porous structure along the heat source direction is shown in formula (9): (9) in, represents the pressure drop of the layered gradient porous structure along the heat source direction, represents the actual pressure drop of the first layer of a single porosity porous structure, It represents the actual pressure drop of the second layer single porosity porous structure.

[0023] Example 2. This example provides a method for predicting the pressure drop of a layered porous structure along the direction of a heat source. The method in Example 1 is used. The difference from the method mentioned in Example 1 is that the physical models of single porosity porous structures of different specifications established in this example are: Weaire-Phelan lattice structure single porosity porous structures with porosities of 0.75 and 0.95, respectively, and the cell size is 5 mm. The pressure drop of each single porosity porous structure in the inlet fluid velocity range of 10-25 m / s is calculated by simulation. The layered porous structure model includes a stacked single porosity porous structure with a Weaire-Phelan lattice structure of 0.75 and a single porosity porous structure with a Weaire-Phelan lattice structure of 0.95. The length of the layered porous structure model along the direction of the heat source is 10 mm, and the two layers each account for 50%. The actual flow rate of each layer of the single porosity porous structure in this example is as follows: Figure 3 In this embodiment, the relationship between the actual inlet fluid velocity and the theoretical inlet fluid velocity of each layer of the single porosity porous structure is as follows: Figure 4 shown.

[0024] This embodiment also establishes a real layered model, including a Weaire-Phelan lattice structure single porosity porous structure with a porosity of 0.75 and a Weaire-Phelan lattice structure single porosity porous structure with a porosity of 0.95. The layered porous structure model is 10 mm long along the heat source direction, and the two layers each account for 50%. Fluent software is used to simulate and obtain the pressure drop. In this embodiment, the maximum error between the predicted pressure drop and the actual simulated pressure drop is 1.1%. Figure 5 shown.

[0025] Example 3, this example provides a method for predicting the pressure drop of a layered porous structure along the direction of a heat source, using the method in Example 1, which is different from the method mentioned in Example 1: the physical models of single porosity porous structures of different specifications established in this example are: Weaire-Phelan lattice structure single porosity porous structures with porosities of 0.8 and 0.9, respectively, and the cell size is 5 mm. The pressure drop of each single porosity porous structure in the range of inlet fluid velocity of 10-25 m / s is calculated by simulation. The layered porous structure model includes a stacked Weaire-Phelan lattice structure single porosity porous structure with a porosity of 0.8 and a Weaire-Phelan lattice structure single porosity porous structure with a porosity of 0.9. The length of the layered porous structure model along the direction of the heat source is 10 mm, and the two layers each account for 50%.

[0026] In this embodiment, a real layered model is also established, including a Weaire-Phelan lattice structure single porosity porous structure with a porosity of 0.8 and a Weaire-Phelan lattice structure single porosity porous structure with a porosity of 0.9. The layered porous structure model is 10 mm long along the heat source direction, and the two layers each account for 50%. Fluent software is used to simulate and obtain the pressure drop. In this embodiment, the maximum error between the predicted pressure drop and the actual simulated pressure drop is 0.9%, as shown in FIG. Figure 6 shown.

[0027] Example 4. This example provides a method for predicting the pressure drop of a layered porous structure along the direction of a heat source. The method in Example 1 is used. The difference from the method mentioned in Example 1 is that the physical models of single porosity porous structures of different specifications established in this example are: Weaire-Phelan lattice structure single porosity porous structures with porosities of 0.75 and 0.95, respectively, and the cell size is 5 mm. The pressure drop of each single porosity porous structure in the range of inlet fluid velocity of 10-25 m / s is calculated by simulation. The layered porous structure model includes a stacked Weaire-Phelan lattice structure single porosity porous structure with a porosity of 0.75 and a Weaire-Phelan lattice structure single porosity porous structure with a porosity of 0.95. The length of the layered porous structure model along the direction of the heat source is 20 mm, and the two layers each account for 50%.

[0028] This embodiment also establishes a real layered model, including a Weaire-Phelan lattice structure single porosity porous structure with a porosity of 0.75 and a Weaire-Phelan lattice structure single porosity porous structure with a porosity of 0.95. The layered porous structure model is 20 mm long along the heat source direction, and the two layers each account for 50%. Fluent software is used to simulate and obtain the pressure drop. In this embodiment, the maximum error between the predicted pressure drop and the actual simulated pressure drop is 1.45%. Figure 7 shown.

[0029] Example 5, this example provides a method for predicting the pressure drop of a layered porous structure along the heat source direction, using the method in Example 1, which is different from the method mentioned in Example 1: the physical models of single porosity porous structures of different specifications established in this example are: Weaire-Phelan lattice structure single porosity porous structures with porosities of 0.75 and 0.95, respectively, and the cell size is 5mm. The pressure drop of each single porosity porous structure in the inlet fluid velocity range of 10-25m / s is calculated by simulation. The layered porous structure model includes stacked Weaire-Phelan lattice structure single porosity porous structures with a porosity of 0.75 and Weaire-Phelan lattice structure single porosity porous structures with a porosity of 0.95. The length of the layered porous structure model along the heat source direction is 20 mm. The single porosity porous structures with a porosity of 0.75 and the single porosity porous structures with a porosity of 0.95 and the single porosity porous structures with a porosity of 0.95 account for 75%.

[0030] This embodiment also establishes a real layered model, including a Weaire-Phelan lattice structure single porosity porous structure with a porosity of 0.75 and a Weaire-Phelan lattice structure single porosity porous structure with a porosity of 0.95. The length of the layered porous structure model along the heat source direction is 20 mm, the Weaire-Phelan lattice structure single porosity porous structure with a porosity of 0.75 accounts for 75%, and the Weaire-Phelan lattice structure single porosity porous structure with a porosity of 0.95 accounts for 25%, and the Fluent software is used to simulate and obtain the pressure drop. In this embodiment, the maximum error between the predicted pressure drop and the actual simulated pressure drop is 1.45%, as shown in FIG. Figure 8 shown.

[0031] The embodiments of the present invention are given for the purpose of illustration and description, and are not intended to be exhaustive or to limit the invention to the disclosed forms. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments are selected and described in order to better illustrate the principles and practical applications of the present invention and to enable those of ordinary skill in the art to understand the present invention and thereby design various embodiments with various modifications suitable for specific uses.

Claims

1. A method for predicting the pressure drop of a layered porous structure along the direction of a heat source, characterized in that: The steps include: S1. Establishing physical models of single porosity porous structures of different specifications, respectively, calculating the pressure drop of each single porosity porous structure at different inlet fluid velocities, and establishing a model between the inlet fluid velocity and the pressure drop of the single porosity porous structure; S2. constructing a hierarchical porous structure model, confirming the total flow rate of the inlet fluid flowing into the hierarchical porous structure model, and confirming the actual flow rate of each layer of the single porosity porous structure in the hierarchical porous structure model; S3. Obtaining the actual inlet fluid velocity of each layer of the single porosity porous structure according to the actual flow rate of each layer of the single porosity porous structure obtained in step S2, and obtaining the actual pressure drop of each layer of the single porosity porous structure in the layered porous structure model according to the model between the inlet fluid velocity and the pressure drop of the single porosity porous structure obtained in step S1; S4. Taking an average of the actual pressure drops of the single-porosity porous structures of each layer obtained in step S3, the pressure drop of the layered gradient porous structure along the heat source direction is obtained.

2. The method for predicting the pressure drop of a layered porous structure along the heat source direction according to claim 1, characterized in that: In the step S1, the single porosity porous structure is selected from one of a Weaire-Phelan lattice structure, a Kelvin lattice structure and a BCC lattice structure.

3. The method for predicting the pressure drop of a layered porous structure along the heat source direction according to claim 1, characterized in that: In the step S1, the porosity range of the single porosity porous structure is: 0.7~0.

95.

4. The method for predicting the pressure drop of a layered porous structure along the heat source direction according to claim 1, characterized in that: In step S1, the model between the inlet fluid velocity and the pressure drop of the single porosity porous structure is shown in formula (1): （1） in, is the pressure drop per unit length, is the inlet fluid velocity, represents a linear constant, Represents a quadratic constant.

5. The method for predicting the pressure drop of a layered porous structure along the heat source direction according to claim 1, characterized in that: In step S2, the layered porous structure model is formed by stacking single-porosity porous structures with different porosities along the direction of the heat source, and the connecting rods of two layers of single-porosity porous structures are stepped transition or smooth transition.

6. The method for predicting the pressure drop of a layered porous structure along the heat source direction according to claim 1, characterized in that: In step S2, the total flow rate of the inlet fluid flowing into the hierarchical porous structure model is as shown in formula (2): （2） in, represents the total inlet fluid flow rate of the layered porous structure model, represents the fluid density, is the inlet fluid velocity, Indicates the fluid inlet cross-sectional area.

7. The method for predicting the pressure drop of a layered porous structure along the heat source direction according to claim 1, characterized in that: In step S2, the actual flow rate of each layer of the single porosity porous structure in the layered porous structure model is shown in formula (3) and formula (4): （3） （4） in, represents the total inlet fluid flow rate of the layered porous structure model, represents the actual flow rate entering the first layer of the single porosity porous structure, represents the actual flow rate entering the second layer of the single porosity porous structure, represents the pressure drop of the first layer of a single porosity porous structure, Represents the pressure drop of the second layer of single porosity porous structure.

8. The method for predicting the pressure drop of a layered porous structure along the heat source direction according to claim 1, characterized in that: In step S3, the actual inlet fluid velocity of each layer of the single porosity porous structure obtained in step S2 is obtained according to the actual flow rate of each layer of the single porosity porous structure as shown in formulas (5) and (6): （5） （6） in, represents the actual inlet fluid velocity of the first layer of a single porosity porous structure, represents the actual flow rate entering the first layer of the single porosity porous structure, represents the total inlet fluid flow rate of the layered porous structure model, is the inlet fluid velocity, represents the actual inlet fluid velocity of the second layer of the single porosity porous structure, Represents the actual flow rate entering the second layer of single porosity porous structure.

9. The method for predicting the pressure drop of a layered porous structure along the heat source direction according to claim 1, characterized in that: In step S3, the pressure drop of each layer of the single porosity porous structure in the layered porous structure model is shown in formula (7) and formula (8): （7） （8） in, represents the actual pressure drop of the first layer of a single porosity porous structure, The linear constant representing the first layer of the single porosity porous structure, represents the actual inlet fluid velocity of the first layer of a single porosity porous structure, The quadratic constant representing the first layer of single porosity porous structure, represents the actual pressure drop of the second layer of single porosity porous structure, The linear constant representing the second layer single porosity porous structure, represents the actual inlet fluid velocity of the second layer of the single porosity porous structure, Represents the quadratic constant of the second layer single porosity porous structure.

10. The method for predicting the pressure drop of a layered porous structure along the heat source direction according to claim 1, characterized in that: In step S4, the pressure drop of the layered gradient porous structure along the heat source direction is as shown in formula (9): （9） in, represents the pressure drop of the layered gradient porous structure along the heat source direction, represents the actual pressure drop of the first layer of a single porosity porous structure, It represents the actual pressure drop of the second layer single porosity porous structure.

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