A Visual Simulation Method for Evaluating the Consistency of Flow Distribution in Fuel Cell Stacks

Abstract

This invention relates to the field of fuel cells, specifically to a visual simulation method for evaluating the consistency of flow distribution in a fuel cell stack. It includes the following steps: S1, establishing a simplified geometric model of the stack flow channels; S2, generating interfaces between the inlet manifold, outlet manifold, and the stack core, and naming the boundary surfaces; S3, meshing the processed geometric model; S4, setting boundary conditions in the simulation software; S5, extracting the actual flow values ​​of each individual cell sub-channel; S6, calculating the deviation rate of each individual cell sub-channel using a uniformity formula; S7, presetting deviation rate parameter values, filtering out individual cell flow channel numbers exceeding the deviation rate parameter values, and controlling the deviation rate of all individual cell sub-channels to be within -P to +P. This invention can quickly obtain the flow distribution of individual cells at different locations during the stack flow channel structure design, providing accurate visual basis for stack structure design, with a short cycle time and low cost.

Description

Technical Field

[0001] This invention relates to the field of fuel cells, and in particular to a visual simulation method for evaluating the consistency of flow distribution in a fuel cell stack. Background Technology

[0002] The fuel cell stack is a crucial component of a fuel cell system, comprising multiple individual cells, end plates, insulating plates, electrode plates, disc springs, and bolts. It's an assembly that generates direct current through the electrochemical reaction of hydrogen and air, simultaneously producing heat, water, and other byproducts. The structural design of the stack's flow channels determines the uniformity of gas and coolant distribution, significantly impacting the stack's reaction efficiency and power density. Existing fuel cell stack structures generally consist of the stack core, inlet manifold, and outlet manifold. The core contains numerous individual cells with flow channels. Since the structural design cannot guarantee the uniformity of gas flow distribution across all individual cells, prototype fabrication and performance testing are necessary to analyze the distribution uniformity.

[0003] However, when designing a new fuel cell stack flow channel structure, it is not possible to quickly obtain the uniformity of flow distribution in a single cell. Performance tests can only be conducted after the design is completed and a prototype is made. The flow distribution is inferred by analyzing the voltage distribution, which has the disadvantages of long cycle, high cost and lack of intuitiveness. Summary of the Invention

[0004] The purpose of this invention is to address the problems existing in the background technology by proposing a visual simulation method for evaluating the consistency of flow distribution in fuel cell stacks. This method can quickly obtain the flow distribution of single cells at different locations during the design of the stack flow channel structure, providing accurate visual basis for stack structure design. It has a short cycle time and low cost.

[0005] The technical solution of this invention, a visual simulation method for evaluating the consistency of flow distribution in a fuel cell stack, includes the following steps:

[0006] S1. Establish a simplified geometric model of the fuel cell stack flow channel;

[0007] S2. Generate an interface surface between the inlet manifold, the outlet manifold, and the fuel cell core, and name the boundary surface.

[0008] S3. Mesh the processed geometric model;

[0009] S4. Set boundary conditions in the simulation software, including the selection of the physical model, the parameters of the flowing medium, and the flow rate, pressure, and temperature parameters at the inlet and outlet boundary surfaces;

[0010] S5. In the simulation software, the middle surface of the stack core is separated into the cross-section of each individual cell flow channel with the actual number of pieces. Each sub-flow channel is assigned a serial number, and the actual flow rate value Q' of each individual cell sub-flow channel is extracted.

[0011] S6. Calculate the deviation rate of each cell sub-channel using the uniformity formula:

[0012]

[0013] in, This is the theoretical design flow rate for a single-cell flow channel;

[0014] S7. Preset the deviation rate parameter value P, filter out the single-cell flow channel number that exceeds the deviation rate parameter value, find the corresponding flow channel in the simulation software and lock it, and make corresponding structural adjustments to the corresponding position of the main pipe to control the deviation rate of all single-cell sub-flow channels to be within -P to +P, so as to meet the set flow distribution consistency requirements.

[0015] Preferably, in S1, the 3D model of the fuel cell stack is imported into the preprocessing module of the simulation software, and then the flow channel extraction function is used to close the flow channels of the fuel cell stack inlet manifold and outlet manifold models respectively, extracting the complete flow channel models of the inlet manifold and outlet manifold, and establishing a simplified solid model of the fuel cell stack core between the inlet manifold and outlet manifold.

[0016] Preferably, in S2, the pressure data of the inlet manifold, outlet manifold, and fuel cell core are extracted to obtain the flow resistance value.

[0017] Preferably, in S6, the actual flow rate values ​​Q' of all single cell sub-channel cross sections are stored in a record file and copied to an Excel spreadsheet, and then the deviation rate is calculated using the uniformity formula.

[0018] Preferably, the preset deviation rate parameter value P is 5%.

[0019] Preferably, the flow channel serial numbers of single cells exceeding 5% are found based on the statistical results in the Excel table.

[0020] Preferably, if the deviation rate is greater than 5%, it indicates that the flow rate of the channel is too high. In this case, the flow velocity at the corresponding position of the main pipe is increased to reduce the pressure at that position, thereby reducing the flow rate of the channel. If the deviation rate is less than -5%, it indicates that the flow rate of the channel is too low. In this case, the flow velocity at the corresponding position of the main pipe is decreased to increase the inlet pressure, thereby increasing the flow rate of the channel. After repeated structural adjustments and calculation iterations, the deviation rate of all single cell sub-channels is finally within -5% to +5%.

[0021] Compared with existing technologies, this invention has the following beneficial technical effects: This invention can quickly obtain the flow distribution of single cells at different locations during fuel cell stack flow channel structure design, and can screen out the optimal structural design without processing multiple fuel cell stack structures into prototypes, providing a precise visual basis for fuel cell stack structure design. It has a short cycle time and low cost. Without the need for prototype processing and testing, it can quickly identify single cells with lower flow distribution, providing a basis for specific design improvements. Through repeated adjustments, the flow distribution uniformity can be adjusted to the design target value. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the method flow of the present invention;

[0023] Figure 2 A 3D model diagram of the fuel cell stack structure;

[0024] Figure 3 A simplified geometric model of the fuel cell stack flow channel is shown. Detailed Implementation

[0025] like Figures 1-3 As shown in this embodiment, a visualization simulation method for evaluating the consistency of flow distribution in a fuel cell stack includes the following steps:

[0026] S1. Establish a simplified geometric model of the fuel cell stack flow channel: Import the 3D model of the fuel cell stack into the preprocessing module of the simulation software, and then use the flow channel extraction function to close the flow channels of the fuel cell stack inlet manifold and outlet manifold models respectively, extract the complete flow channel models of the inlet manifold and outlet manifold, and establish a simplified solid model of the fuel cell stack core between the inlet manifold and outlet manifold.

[0027] S2. Generate an interface surface between the inlet manifold, the outlet manifold, and the fuel cell core. Extract the pressure data of the inlet manifold, the outlet manifold, and the fuel cell core respectively to obtain the flow resistance value and name the boundary surface.

[0028] S3. Mesh the processed geometric model;

[0029] S4. Set boundary conditions in the simulation software, including the selection of the physical model, the parameters of the flowing medium, and the flow rate, pressure, and temperature parameters at the inlet and outlet boundary surfaces;

[0030] S5. In the simulation software, the middle surface of the fuel cell stack core is separated into the cross-section of each individual cell flow channel (1, 2, 3, ..., n) according to the actual number of slices. Each sub-flow channel is assigned a serial number, and the actual flow rate value Q' of each individual cell sub-flow channel is extracted for subsequent processing.

[0031] S6. Submit the calculation. When the residual value reaches the set value, the calculation is complete. Copy the flow rate values ​​Q' (Q' is the actual flow rate of a single cell sub-channel) of all sub-channel sections in the record file to an Excel spreadsheet. Calculate the deviation rate of each single cell sub-channel using the uniformity formula:

[0032]

[0033] in, This is the theoretical design flow rate for a single-cell flow channel;

[0034] At this point, the exact flow rate of each individual cell channel can be clearly seen, and it can be determined whether the flow rate of each individual cell channel is more or less than the average value (the design flow rate of the individual cell channel).

[0035] S7. Set the preset deviation rate parameter value to 5%. Based on the statistical results in the Excel spreadsheet, find the single-cell flow channel number with a deviation rate exceeding 5%. Locate the corresponding flow channel in the simulation software, lock the flow channel, and make corresponding structural adjustments to the corresponding position of the main pipe. Specifically, if the deviation rate is greater than 5%, it indicates that the flow rate of the flow channel is too high. Increase the flow velocity at the corresponding position of the main pipe to reduce the pressure at that point, thereby reducing the flow rate of the flow channel. If the deviation rate is less than -5%, it indicates that the flow rate of the flow channel is too low. Decrease the flow velocity at the corresponding position of the main pipe to increase the inlet pressure by 0-5%, thereby increasing the flow rate of the flow channel. After repeated structural adjustments and calculation iterations, the deviation rate of all single-cell sub-flow channels is finally within -5% to +5%, meeting the set flow distribution consistency requirements. Only then can the stack structure that finally meets the consistency requirements be processed.

[0036] This embodiment enables rapid acquisition of single-cell flow distribution at different locations during fuel cell stack flow channel structure design. It allows for the selection of the optimal structural design without the need for prototyping multiple fuel cell stack structures, providing a precise visual basis for stack structure design. This approach is time-efficient and cost-effective. This embodiment offers specific quantitative and visual methods for consistent fuel cell stack flow distribution design, allowing for intuitive viewing in simulation software. Without the need for prototyping and testing, it can quickly identify single cells with lower flow distribution, providing a basis for specific design improvements. Through repeated adjustments, the flow distribution uniformity can be adjusted to the design target value.

[0037] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited thereto. Various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention.

Claims

1. A visual simulation method for evaluating the consistency of flow distribution in a fuel cell stack, characterized in that, Includes the following steps: S1. Establish a simplified geometric model of the fuel cell stack flow channel; S2. Generate an interface surface between the inlet manifold, the outlet manifold, and the fuel cell core, and name the boundary surface. S3. Mesh the processed geometric model; S4. Set boundary conditions in the simulation software, including the selection of the physical model, the parameters of the flowing medium, and the flow rate, pressure, and temperature parameters at the inlet and outlet boundary surfaces; S5. In the simulation software, the middle surface of the stack core is separated into the cross-section of each individual cell flow channel with the actual number of pieces. Each sub-flow channel is assigned a serial number, and the actual flow rate value Q' of each individual cell sub-flow channel is extracted. S6. Calculate the deviation rate of each cell sub-channel using the uniformity formula: Deviation rate = ; in, This is the theoretical design flow rate for a single-cell flow channel; S7. A preset deviation rate parameter value P is used to filter out single-cell flow channel numbers exceeding this value. The corresponding flow channels are located and locked in the simulation software. Structural adjustments are made to the corresponding positions in the main pipe to control the deviation rate of all single-cell sub-flow channels to be within -P to +P, meeting the set flow distribution consistency requirements. The preset deviation rate parameter value P is 5%. Based on the statistical results in the Excel sheet, single-cell flow channel numbers exceeding 5% are found. If the deviation rate is greater than 5%, it indicates that the flow rate of that channel is too high. The flow velocity at the corresponding position in the main pipe is increased to reduce the pressure at that point, thereby reducing the flow rate of that channel. If the deviation rate is less than -5%, it indicates that the flow rate of that channel is too low. The flow velocity at the corresponding position in the main pipe is decreased to increase the inlet pressure, thereby increasing the flow rate of that channel. After repeated structural adjustments and iterative calculations, the deviation rate of all single-cell sub-flow channels is finally achieved to be within -5% to +5%.

2. The visualization simulation method for evaluating the consistency of flow distribution in a fuel cell stack according to claim 1, characterized in that, In S1, the 3D model of the fuel cell stack is imported into the preprocessing module of the simulation software. Then, the flow channel extraction function is used to close the flow channels of the fuel cell stack inlet manifold and outlet manifold models respectively, extract the complete flow channel models of the inlet manifold and outlet manifold, and establish a simplified solid model of the fuel cell stack core between the inlet manifold and outlet manifold.

3. The visualization simulation method for evaluating the consistency of flow distribution in a fuel cell stack according to claim 2, characterized in that, In S2, the pressure data of the inlet manifold, outlet manifold, and fuel cell core are extracted to obtain the flow resistance value.

4. The visualization simulation method for evaluating the consistency of flow distribution in a fuel cell stack according to claim 3, characterized in that, In S6, the actual flow rate values ​​Q' of all single cell sub-channel cross sections are stored in a record file and copied to an Excel spreadsheet. Then, the deviation rate is calculated using the uniformity formula.

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