Cooling fan performance calculation method based on multi-physics field coupling

Abstract

The invention provides a cooling fan performance calculation method based on multi-physics field coupling. The cooling fan performance calculation method comprises the following steps that a parameterized geometric model of a fluid domain is established according to the size and the relative position of an engine cooling fan and a wind chamber test bed; respectively inputting the two parameterized geometric models into pretreatment software, respectively carrying out grid division on the two parameterized geometric models by using a grid division tool, and outputting a grid file after geometric discretization of the two parameterized geometric models; the discrete grid file of the engine cooling fan is imported into finite element analysis software, a pretreatment tool is used for defining material parameters for the engine cooling fan, boundary conditions and load constraints are applied, the discrete grid file of a fluid domain is imported into fluid dynamics analysis software, and fluid dynamics analysis is carried out on the engine cooling fan; setting a turbulence model, region and boundary conditions, a solver and the like; establishing a multi-physical field coupling model to realize data exchange among a plurality of physical fields; and operation calculation is carried out, a calculation result is post-processed, and qualitative and quantitative analysis is carried out on the fan performance.

Description

Technical Field

[0001] The present invention relates to the field of heat dissipation of engine cooling systems, and particularly to a method for calculating the performance of a cooling fan based on multi-physics field coupling. Background Art

[0002] The cooling fan is a key component in the engine cooling system. It accelerates the air flow through the radiator, improves the heat dissipation efficiency of the radiator, enables the engine to operate at an appropriate ambient temperature, and thus ensures the efficient, stable and safe operation of the engine. With the continuous development of numerical analysis methods and numerical simulation software, CAE technology has been introduced into the performance development process of cooling fans, greatly reducing the R & D cost of cooling fans and improving the efficiency of their performance R & D at the same time.

[0003] However, the existing calculation methods for cooling fans are mainly based on a single physical field model, such as a fluid dynamics model or a structural finite element model. Due to the complex working environment of the engine cooling fan, which involves the interaction of multiple physical fields such as fluid, temperature and structure, a single physical field model is often difficult to accurately describe the working state of the cooling fan. Lin Huibin et al. in the method for calculating the strength of an engine cooling fan assembly based on unidirectional fluid-structure coupling (CN116257953A) considered the influence of the flow field pressure on the blade structural strength, but did not consider the influence of the fan blade deformation on the flow field, nor the influence of temperature on the fan performance. Therefore, a calculation method that can comprehensively consider the influence of multiple physical fields is needed to improve the accuracy of the performance calculation of engine cooling fans. Summary of the Invention

[0004] In order to improve the accuracy of the performance calculation of the engine cooling fan, provide reliable reference data for the structural development of the engine cooling fan, thereby improving the R & D efficiency of the engine cooling fan and reducing the R & D cost, the present invention discloses a method for calculating the performance of a cooling fan based on multi-physics field coupling.

[0005] The present invention is achieved at least by one of the following technical solutions.

[0006] A method for calculating the performance of a cooling fan based on multi-physics field coupling includes the following steps:

[0007] (1) Use 3D modeling software to establish a parametric geometric model of the engine cooling fan, and establish a parametric geometric model of the fluid domain according to the size and relative position of the engine cooling fan and the wind chamber test bench;

[0008] (2) Input the two parametric geometric models established in step (1) into the pre-processing software respectively, and use the mesh generation tool to discretize the parametric geometric model of the engine cooling fan and the parametric geometric model of the fluid domain used to simulate the wind chamber test respectively, and output the mesh file after geometric discretization;

[0009] (3) Import the meshed file of the engine cooling fan after discretization into the structural finite element analysis software. Use the preprocessing tool to define the material parameters for the engine cooling fan, and apply boundary conditions and load constraints. Import the meshed file of the fluid domain after discretization into the computational fluid dynamics analysis software, and set the turbulence model, regions, boundary conditions, and spatial discretization format.

[0010] (4) Establish a multi-physics coupling model with the fan blade surface as the coupling surface to enable data exchange between multiple physical fields. Determine the number of iteration steps and coupling steps to control the calculation and termination of the entire process. When the internal iteration converges or reaches the maximum number of iteration steps, the current coupling terminates and enters the next coupling step until the maximum number of coupling steps is reached, at which point the calculation terminates.

[0011] (5) Run the calculation and post-process the calculation results. Plot the pressure contour map for qualitative analysis of the fan performance, and plot the characteristic curves of the fan performance parameters for quantitative analysis of the fan performance.

[0012] Furthermore, the engine cooling fan in step (1) is formed by injection molding of a support plate and fan blades. The support plate has bolt holes, and the support plate is fixedly connected to the clutch end cover by bolts.

[0013] Furthermore, in step (1), the wind chamber test bench is simplified using the parametric geometric model of the fluid domain. The auxiliary fan and the fan drive motor in the test bench are omitted, and the inlet flow rate and fan speed are set in the finite element software.

[0014] Furthermore, in step (2), the engine cooling fan is discretized using tetrahedral elements. Since the fan blades are periodically symmetrically distributed, only one fan blade needs to be intercepted for meshing, and then it is periodically rotated and replicated, and co-noded with the support plate to obtain a complete fan mesh model.

[0015] Furthermore, in step (2), the parametric geometric model of the fluid domain is discretized using a combination of tetrahedral and hexahedral elements. The rotating region around the fan is encrypted using tetrahedral elements, and the external fluid domain is discretized using larger-sized hexahedral elements to reduce the number of elements. Tetrahedral elements are used for transition between the fan rotating region and the external fluid domain, and different regions are connected through the interface. Data is transferred by interpolation during the calculation.

[0016] Further, in step (3), the material parameters of the engine cooling fan specifically include material density, elastic modulus, and Poisson's ratio. The boundary conditions refer to establishing reference points at the center positions of all bolt holes and the center position of the shaft hole, coupling the reference points of all bolt holes to the center of the shaft hole, and constraining the degrees of freedom displacement of the coupling points in the X, Y, and Z directions to 0. The load constraint refers to adding gravitational acceleration and rotational speed to consider gravity and rotational centrifugal force;

[0017] Further, in step (3), the fluid is regarded as an incompressible fluid, and the turbulence model adopts the SST k-ω model. The size of the rotating region around the fan is determined according to the size of the fan and the position of the air shroud. The distances from the front and rear end faces of the rotating region to the front and rear of the fan are respectively taken as 0.15 - 0.3 times the projected width of the fan. The cylindrical side surface is consistent with the inner cylindrical surface of the air shroud. The fluid domain solver adopts a pressure-based solver. The inlet is a mass flow inlet, and the outlet is a pressure outlet. The spatial discretization format adopts the second order.

[0018] Further, in step (4), the physical fields include the temperature field, the flow field, and the structural field. The flow field and the structural field are solved in a fluid dynamics solver and a structural mechanics solver respectively. At the beginning of each coupling step, the data of the blade surface pressure and the deformed node positions are transferred between the coupling surfaces by interpolation, and then iterative solutions are carried out in each solver respectively; regarding the temperature field, considering the working environment of the blade, the influence of temperature on the flow field is ignored, and it is assumed that the overall temperature of the blade is constant. The influence of temperature on the fan performance is calculated by giving the material parameters of the blade at different temperatures.

[0019] Further, the calculation results of step (5) include the structural performance parameters and the aerodynamic performance parameters of the fan. Among them, the structural performance parameters include the stress and deformation of the blade and the support plate, and the aerodynamic performance parameters include the air volume, static pressure, and static pressure efficiency generated by the fan under the working condition.

[0020] Further, the post-processing in step (5) specifically refers to drawing the blade surface pressure nephogram and the fan deformation nephogram, judging the position of the pressure center, drawing the fan static pressure - flow curve, efficiency - flow curve, and the curve of the maximum deformation of the blade varying with the flow rate. If it is a benchmark fan, the calculation results can be compared with the test results to determine the calculation error. If it is a modified fan, the calculation results can be corrected according to the benchmark error first, and then it can be judged whether the aerodynamic performance of this fan meets the design requirements.

[0021] Compared with the existing technology, the beneficial effects of the present invention are:

[0022] (1) The present invention simulates the scenario of the engine cooling fan under the combined action of multiple physical fields, which is more in line with the actual working environment. Compared with the situation of only considering a single physical field, the calculation accuracy is higher, and it has more reference value for the structural development of the engine cooling fan. In addition, the present invention considers the influence of the temperature field by specifying material parameters at different temperatures, avoiding the direct participation of the temperature field in the coupling and improving the calculation efficiency.

[0023] (2) The method proposed by the present invention has higher calculation accuracy compared with the situation of only considering a single physical field, and has more reference value for the structural development of the engine cooling fan.

[0024] (3) The present invention considers the influence of the temperature field by specifying material parameters at different temperatures, avoiding the participation of the temperature field in the coupling and improving the calculation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a flowchart of a method for calculating the performance of a cooling fan based on multi-physical field coupling according to the present invention;

[0026] Figure 2 is a parametric geometric model diagram of the fan established in the embodiment of the present invention;

[0027] Figure 3 is a parametric geometric model diagram of the fluid domain established in the embodiment of the present invention;

[0028] Figure 4 is a fan mesh model diagram divided in the embodiment of the present invention;

[0029] Figure 5 is a fluid domain mesh model diagram established in the embodiment of the present invention;

[0030] Figure 6 is a schematic diagram of data transfer between coupling surfaces in the embodiment of the present invention;

[0031] Figure 7 is a fan static pressure-flow curve diagram calculated by using different calculation methods in the embodiment of the present invention;

[0032] Figure 8 is a fan static efficiency-flow curve diagram calculated by using different calculation methods in the embodiment of the present invention;

[0033] Figure 9 is a surface pressure contour map of the fan blade calculated by using different calculation methods in the embodiment of the present invention;

[0034] Figure 10 is a fan blade deformation diagram calculated by considering multi-physical fields and only considering a single physical field in the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the specification of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts are within the scope of protection of the present invention.

[0036] A method for calculating the performance of a cooling fan based on multi-physical field coupling in this embodiment is as Figure 1 shown, and mainly includes the following steps:

[0037] (1) Use the three-dimensional modeling software UG to establish a parametric geometric model of the engine cooling fan according to the actual working requirements. As Figure 2 shown, this geometric model is assembled by a support plate 1 and fan blades 2. Eleven blades are symmetrically distributed periodically, the support plate has bolt holes, and the support plate is fixedly connected to the clutch end cover by bolts. As an embodiment of the present invention, the fan has a total of 13 blades and is symmetrically distributed periodically. The maximum diameter of the fan blade is 780 mm, the maximum projection width is 128 mm, the maximum diameter of the support plate is 327 mm, the thickness is 5 mm, the diameter of the shaft hole of the support plate is 180 mm, the diameter of the bolt hole is 10 mm, and a gasket with a radial thickness of 2 mm is added to the bolt hole. According to the dimensions and relative positions of the engine cooling fan and the wind chamber test bench, use the three-dimensional modeling software to establish a parametric geometric model of the fluid domain. The parametric geometric model of the fluid domain is a virtual wind chamber established by simplifying on the basis of the wind chamber test bench, such as ignoring the fan drive motor and the auxiliary fan for controlling the air volume size, etc. As Figure 3 shown, the maximum length of the entire fluid domain is 7000 mm, the maximum diameter is 4000 mm, the length of the rotating area is 197 mm, the front end of the fan is 36 mm away from the front end face of the rotating area, the rear end of the fan is 33 mm away from the rear end face of the rotating area, the maximum diameter of the rotating area is 830 mm, and the transition area is used for the transition of the grid between the rotating area and the external fluid domain. The main purpose is to ensure uniform transition of the grid and avoid numerical dissipation caused by grid mutation;

[0038] (2) Input the parametric geometric models established in steps (1) and (2) into the mesh generation software HyperMesh respectively, and use the mesh generation tools to mesh the geometric model of the engine cooling fan and the fluid domain model for simulating the wind chamber test. The specific mesh generation is to discretize the engine cooling fan using tetrahedral elements. Since the fan blades are periodically symmetrically distributed, only one fan blade needs to be intercepted for meshing, and then it is periodically rotated and copied, and co-noded with the pallet to obtain the complete fan mesh model. The parametric geometric model of the fluid domain is meshed using a combination of tetrahedral and hexahedral elements. Among them, the rotating area around the fan is encrypted with tetrahedral elements, and the external fluid domain is meshed with hexahedral elements to reduce the number of elements. Tetrahedral elements are used for transition between the fan rotating area and the external fluid domain.

[0039] As an embodiment of the present invention, the fan is meshed using tetrahedral elements. The minimum element size of the mesh at the fillet of the fan blade is 2 mm, and the maximum element size at other positions is 8 mm. The pallet is meshed with a 3 mm element size. The part connecting the pallet and the fan blade is co-noded to obtain the fan mesh model as Figure 4 shown. The fluid domain is meshed with tetrahedral and hexahedral meshes. Among them, the rotating area around the fan is meshed with tetrahedral meshes. The minimum face element size is determined by the minimum element size of the fan, and the maximum face mesh size is 25 mm. The volume mesh is generated by interpolating the face mesh. The external fluid domain is meshed with hexahedral meshes, and the maximum face mesh size is 120 mm. The size of the transition mesh area gradually increases from the position of the rotating area to the external fluid domain. The fluid domain mesh is as Figure 5 shown (only the face mesh is shown in the figure). To ensure the calculation accuracy, ensure that the distortion of all tetrahedral elements is not greater than 0.85 and the collapse rate is not less than 0.2. Finally, output the mesh files after geometric discretization of the two respectively;

[0040] (3) Import the mesh file of the discretized engine cooling fan into the structural finite element analysis software, and use the preprocessing tool to define the material parameters for the engine cooling fan. In this embodiment, it is assumed that the working environment of the engine cooling fan is 60 °C, the material of the fan blade is PA6+GF30, the material density is 1360 kg / m3, the elastic modulus is 5 GPa, and the Poisson's ratio is 0.41. Reference points are established at the center positions of all bolt holes and the center position of the shaft hole. The reference points of all bolt holes are coupled to the center of the shaft hole, and the degrees of freedom displacements of the coupled points along the X, Y, and Z directions are constrained to be 0. Add a gravitational acceleration g of 9.8 m / s 2And the rotational speed is 1500 rpm to calculate the gravity and rotational centrifugal force. Import the mesh file of the discretized fluid domain into the fluid dynamics analysis software. Set the turbulence model to the SST k-ω model, and describe the motion of the rotating region using the multiple reference frame method. The rotational speed is 1500 rpm, rotating around the Z-axis. Set the air chamber inlet as the mass flow inlet and the outlet as the pressure outlet. Use the pressure-based solver, and all discretization formats use the second-order upwind difference format. In the structural finite element software and the fluid mechanics software, take the fan blade surface as the coupling surface, that is, the pressure from the flow field and the nodal displacement from the structural field are only interpolated and transferred in the coupling region. To ensure the effective interpolation of the field variables, it is necessary to ensure the consistent position of the coupling surface;

[0041] (4) Use workbench software to establish a multi-physics coupling model. The physical fields include the temperature field, the flow field, and the structural field. The flow field and the structural field are solved in the fluid dynamics software solver and the structural mechanics solver respectively. At the beginning of each coupling step, the fan blade surface pressure and the deformed nodal position data are transferred between the coupling surfaces, and then iterative solutions are carried out in each solver respectively. Regarding the temperature field, considering the working environment of the fan blade, ignoring the influence of temperature on the flow field, assuming that the overall temperature of the fan blade is constant, so calculate the influence of temperature on the fan performance by giving the material parameters of the fan blade at different temperatures.

[0042] The specific solution process is as Figure 1 shown. At the beginning of each coupling step, a complete data exchange of the nodal displacement and the fan blade surface pressure is carried out on the coupling surface (as Figure 6 shown), and then calculations are carried out in an iterative manner to ensure the convergence of the iterative process. In this embodiment, the number of sub-steps of the flow field iteration is 300 steps, the time increment of the structural strength calculation is 0.1, the maximum number of iterations in each coupling step is 10, and the number of coupling steps is set to 5. Setting multiple coupling steps ensures the convergence of the calculation results;

[0043] (5) Run the calculation in workbench. The calculation results include the structural performance and aerodynamic performance parameters of the fan. The structural performance parameters include the stress and deformation of the fan blade and the support plate, and the aerodynamic performance parameters include the static pressure and torque of the fan at different flow rate points. Output the corresponding data to the Excel table to calculate the shaft power and static pressure efficiency of the fan:

[0044]

[0045]

[0046] Among them, n is the fan rotational speed, with the unit of rpm, Q is the air chamber inlet flow rate, with the unit of kg / s, T is the calculated fan torque, with the unit of N·m, P stTo calculate the static pressure of the fan in Pa, where P is the shaft power of the fan in kw and η is the static pressure efficiency of the fan. Based on the calculated data, the static pressure - flow rate curve of the cooling fan can be plotted as shown in Figure 7 and the static pressure efficiency - flow rate curve as shown in Figure 8 To demonstrate the advantages of the multi - physical - field coupling method proposed in the present invention over the single - physical - field solution, Figure 7 and Figure 8 the calculation results of the multi - physical - field calculation method proposed in the present invention and the multiple reference frame method (MRF) and sliding mesh method (SMM) in the single - physical - field calculation method are compared. It can be seen that the transient - based sliding mesh method has the highest accuracy, but this method has a high calculation cost. In terms of the steady - state calculation method, the multi - physical - field coupling calculation method used in the present invention has higher accuracy than the commonly used multiple reference frame method. Figure 9 shows the pressure contour maps on the fan blade surface calculated by the three methods. It can be seen that, as shown in (c) of Figure 9 and (b), (a) of Figure 9 , the contour maps of the calculation results of the multi - physical - field coupling method (FSI) adopted in the present invention are closer to those of the transient sliding mesh method (SMM). Figure 10 shows the deformation of the engine cooling fan when operating at a speed of 1500 rpm under a constant temperature field of 60 °C, considering the flow - field pressure and not considering the flow - field pressure. It can be seen that when considering the influence of the flow - field pressure on the fan blade, the maximum deformation amount (t - fsi) and the maximum axial deformation amount (z - fsi) of the fan blade are both reduced compared with the maximum deformation amount (t - unfsi) and the maximum axial deformation amount (z - unfsi) of the fan blade calculated without considering the flow - field pressure, and are approximately half of the original. This shows that the influence of aerodynamic force on the deformation of the fan blade is opposite to the combined influence of gravity and centrifugal force, that is, the aerodynamic force helps to reduce the deformation of the fan blade caused by the combined force of gravity and centrifugal force. It can also be seen from Figure 10 that the influence of the flow rate on the total deformation of the fan blade is small, but has a greater influence on the axial deformation of the fan blade.

[0047] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific embodiments described. Obviously, many modifications and variations can be made according to the content of this specification. These embodiments are selected and specifically described in this specification to better explain the principle and practical application of the present invention, so that those skilled in the relevant technical field can well understand and utilize the present invention.

Claims

1. A cooling fan performance calculation method based on multi-physics field coupling, characterized in that: The following steps are involved: (1) Use 3D modeling software to establish a parametric geometric model of the engine cooling fan, and establish a parametric geometric model of the fluid domain based on the size and relative position of the engine cooling fan and the air chamber test bench; (2) inputting the two parameterized geometric models established in step (1) into the pre-processing software respectively, using a meshing tool to discretize the parameterized geometric model of the engine cooling fan and the parameterized geometric model of the fluid domain used to simulate the wind chamber test respectively, and outputting the mesh files after geometric discretization; (3) Import the discretized mesh file of the engine cooling fan into the structural finite element analysis software, use the pre-processing tool to define the material parameters for the engine cooling fan, and apply boundary conditions and load constraints; import the discretized mesh file of the fluid domain into the fluid dynamics analysis software, set the turbulence model, region and boundary conditions, and spatial discretization format; (4) Establish a multi-physics field coupling model and use the fan blade surface as the coupling surface to realize data exchange between multiple physical fields. Determine the number of iteration steps and coupling steps to control the calculation and termination of the entire process. When the internal iteration converges or reaches the maximum number of iteration steps, the current coupling is terminated and enters the next coupling step until the maximum number of coupling steps is reached and the calculation is terminated. (5) Run the calculation and post-process the calculation results, draw a pressure cloud map to make a qualitative analysis of the fan performance, draw the fan performance parameter characteristic curve, and make a quantitative analysis of the fan performance.

2. The cooling fan performance calculation method based on multi-physical field coupling according to claim 1 is characterized in that: The engine cooling fan in step (1) is formed by a support plate and fan blades by injection molding, wherein the support plate has bolt holes, and the support plate is fixedly connected to the clutch end cover by bolts.

3. The cooling fan performance calculation method based on multi-physical field coupling according to claim 1 is characterized in that: In step (1), the air chamber test bench is simplified using a parametric geometric model of the fluid domain, the auxiliary fan and fan drive motor in the test bench are omitted, and the inlet flow rate and fan speed are set in the finite element software.

4. The cooling fan performance calculation method based on multi-physical field coupling according to claim 1 is characterized in that: In step (2), the engine cooling fan is discretized using tetrahedral units. Since the fan blades are periodically symmetrically distributed, only one of the fan blades needs to be cut to divide the mesh, and then it is periodically rotated and replicated, and the nodes are shared with the support plate to obtain a complete fan mesh model.

5. The cooling fan performance calculation method based on multi-physical field coupling according to claim 1 is characterized in that: In step (2), the parameterized geometric model of the fluid domain is discretized using a mixture of tetrahedrons and hexahedrons, wherein the rotating area around the fan is encrypted using tetrahedron units, and the external fluid domain is discretized using larger hexahedron units to reduce the number of units. Tetrahedron units are used to transition between the fan rotating area and the external fluid domain, and different areas are connected through interfaces. Data is transferred by interpolation during calculation.

6. The cooling fan performance calculation method based on multi-physical field coupling according to claim 1 is characterized in that: In step (3), the material parameters of the engine cooling fan specifically include material density, elastic modulus, and Poisson's ratio. The boundary conditions refer to establishing reference points at the center positions of all bolt holes and the center positions of the shaft holes, coupling the reference points of all bolt holes to the center of the shaft holes, and constraining the degree of freedom displacement of the coupling points along the X, Y, and Z directions to be 0. The load constraint refers to adding gravitational acceleration and rotational speed to take into account gravity and rotational centrifugal force.

7. The cooling fan performance calculation method based on multi-physical field coupling according to claim 1 is characterized in that: In step (3), the fluid is regarded as an incompressible fluid, and the turbulence model adopts the SST k-ω model. The size of the rotating area around the fan is determined according to the size of the fan and the position of the wind shield. The distances from the front and rear end surfaces of the rotating area to the front and rear of the fan are respectively 0.15-0.3 times the projection width of the fan. The side surface of the cylinder is consistent with the cylindrical surface inside the wind shield. The fluid domain solver adopts a pressure-based solver, the inlet is a mass flow inlet, the outlet is a pressure outlet, and the spatial discretization format adopts a second order.

8. The cooling fan performance calculation method based on multi-physical field coupling according to claim 1 is characterized in that: In step (4), the physical fields include temperature field, flow field and structural field. The flow field and structural field are solved in the fluid dynamics solver and the structural mechanics solver respectively. At the beginning of each coupling step, the surface pressure of the fan blade and the deformed node position data are transferred between the coupling surfaces by interpolation, and then iteratively solved in each solver respectively. Regarding the temperature field, the working environment of the fan blade is considered, the influence of temperature on the flow field is ignored, and it is assumed that the overall temperature of the fan blade is constant. The influence of temperature on the fan performance is calculated by giving the material parameters of the fan blade at different temperatures.

9. The cooling fan performance calculation method based on multi-physics field coupling according to claim 1 is characterized in that The calculation results of step (5) include the structural performance parameters and aerodynamic performance parameters of the fan, wherein the structural performance parameters include the stress and deformation of the fan blades and the support plate, and the aerodynamic performance parameters include the air volume, static pressure, and static pressure efficiency generated by the fan in the working state.

10. The cooling fan performance analysis method based on multi-physics field coupling according to claim 1, characterized in that ,The post-processing in step (5) specifically refers to drawing the fan blade surface pressure cloud map and the fan deformation cloud map, determining the ,position of the pressure center, drawing the fan static pressure-flow curve, the efficiency-flow curve and the curve of the maximum deformation of the fan blade varying with the ,flow rate. If it is a benchmark fan, the calculation results can be compared with the test results to ,determine the calculation error. If it is a modified fan, the calculation results can ,be corrected first based on the benchmark error, and then ,determining whether the aerodynamic performance of the fan meets the design requirements.

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