Turbocharger sealing system optimization method and system based on CFD simulation

Abstract

The invention relates to a CFD (computational fluid dynamics) simulation-based turbocharger sealing system optimization method and a CFD simulation-based turbocharger sealing system optimization system. The method comprises the steps that a three-dimensional model of the turbocharger sealing system is provided; establishing a CFD simulation model based on the three-dimensional model; unsteady state analysis is conducted on the CFD simulation model, a simulation result is obtained, and the simulation result comprises a first characteristic parameter of the initial oil leakage section and a second characteristic parameter of the oil leakage surface; the initial oil leakage cross section is a middle position cross section of a sealing ring closest to an oil leakage outlet, the oil leakage surface is an air sealing plate end surface close to the back of the pressure impeller, the first characteristic parameter represents the time when the oil volume fraction of the initial oil leakage cross section reaches a preset value for the first time, and the second characteristic parameter represents the total oil leakage amount of the oil leakage surface in a calculation time domain; according to the first characteristic parameter and the second characteristic parameter, the reliability of the turbocharger sealing system is judged; and optimizing the CFD simulation model according to a simulation result. The optimization design of the sealing system can be effectively guided, and the product research and development cycle is greatly shortened.

Description

Technical Field

[0001] The present invention relates to the technical field of turbocharger simulation analysis, and in particular to a turbocharger sealing system optimization method and system based on CFD simulation. Background Art

[0002] The sealing system is used to isolate the center housing from the turbine and compressor, prevent lubricating oil from entering the compressor and turbine areas, and prevent gas and air from penetrating into the center housing from these areas. However, when the negative pressure in the intake system is too large, the pressure seal will fail, causing the lubricating oil to be sucked into the compressor and enter the cylinder with the pressurized air.

[0003] However, the current performance verification of sealing systems mainly relies on experimental methods, which involves adjusting the structure by changing different optimized designs and trying them one by one. This method consumes a lot of manpower, material resources and time costs.

[0004] In addition, the current experimental verification method is relatively subjective in evaluating the results. It can draw clear conclusions for schemes with significant differences, but it is difficult to make quantitative comparisons for schemes with smaller differences. In addition, the experimental method has limited ability to explain the internal details of the sealing system, and it is difficult to provide directions for further improvement. Summary of the invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the problems of high cost and low precision in the prior art performance verification method of the turbocharger sealing system.

[0006] In order to solve the above technical problems, the present invention provides a turbocharger sealing system optimization method based on CFD simulation, comprising:

[0007] A three-dimensional model of a turbocharger sealing system is provided; wherein the three-dimensional model comprises an intermediate housing, a compression housing, a volute housing, an oil chamber arranged in the intermediate housing, and a compression impeller located on one side of the oil chamber and arranged in the compression housing and the volute housing respectively, the compression impeller being connected to a rotating shaft arranged in the intermediate housing, the rotating shaft sleeve being provided with a shaft sleeve, and the shaft sleeve sleeve being provided with a sealing ring for isolating the compression end gas and the oil chamber;

[0008] Based on the three-dimensional model, a CFD simulation model is established;

[0009] Performing a non-steady-state analysis on the CFD simulation model to obtain simulation results, the simulation results including a first characteristic parameter of an initial oil leakage section and a second characteristic parameter of an oil leakage surface; wherein the initial oil leakage section is a section at a middle position of the sealing ring closest to the oil leakage outlet, the oil leakage surface is an end surface of the air seal plate close to the impeller wheel back, the first characteristic parameter characterizes the time taken for the oil volume fraction in the initial oil leakage section to reach a predetermined value for the first time, and the second characteristic parameter characterizes the total oil leakage of the oil leakage surface in a calculated time domain;

[0010] judging the reliability of a turbocharger sealing system according to the first characteristic parameter and the second characteristic parameter;

[0011] According to the simulation results, the CFD simulation model is optimized.

[0012] In one embodiment of the present invention, a CFD simulation model is established based on the three-dimensional model, including:

[0013] extracting a fluid domain of the three-dimensional model;

[0014] Meshing the fluid domain to obtain a fluid domain mesh model;

[0015] For the fluid domain grid model, CFD calculation boundary conditions are set.

[0016] In one embodiment of the present invention, the fluid domain is meshed to obtain a fluid domain mesh model, including:

[0017] Set the global size of the grid to 2-4mm;

[0018] The grid in the oil film region is set as a hexahedral structure grid, and the hexahedral structure grid is perpendicular to the flow direction of the liquid.

[0019] In one embodiment of the present invention, the CFD calculation boundary conditions include the initial steady-state state of the sealing system, the ratio of liquid and gas in the unsteady process, the liquid surface tension coefficient, the outlet pressure, the gravitational acceleration and the supercharger speed, and the reference pressure.

[0020] In one embodiment of the present invention, performing a non-steady-state analysis on the CFD simulation model includes:

[0021] Select the unsteady-state calculation model and VOF model;

[0022] Substitute the CFD calculation boundary conditions into the model equations, set the time step, output parameters of the calculation results and the convergence factor.

[0023] In one embodiment of the present invention, the method further comprises:

[0024] The output parameter is set to the outlet oil leakage;

[0025] Obtain the oil leakage amount of the outlet in each step of the time step, and in the oil leakage surface, obtain the total oil leakage amount of the oil leakage surface according to the sum of the total oil leakage amount of the outlet in the time step; the time step is set to 5000-8000 steps;

[0026] The time taken for the initial oil leakage section to have an oil volume fraction greater than 4-6% for the first time in the entire timing step is obtained.

[0027] In one embodiment of the present invention, judging the reliability of the turbocharger sealing system according to the first characteristic parameter and the second characteristic parameter includes:

[0028] An oil leakage parameter is obtained according to the difference between the values ​​of the second characteristic parameter and the first characteristic parameter. The smaller the oil leakage parameter is, the higher the reliability of the supercharger sealing system is.

[0029] In one embodiment of the present invention, the CFD simulation model is optimized according to the simulation results, including:

[0030] When the first characteristic parameter reaches a preset threshold, the structure of the oil cavity is modified according to the space utilization and oil drainage of the oil cavity, and the CFD simulation model is re-established to obtain an optimized CFD simulation model;

[0031] According to the optimized CFD simulation model, a non-steady-state analysis is performed in the same manner as the CFD simulation model to obtain an optimized simulation result.

[0032] In one embodiment of the present invention, the structure of the oil chamber is modified according to the utilization and oil discharge conditions of the oil chamber, including:

[0033] Modify the size of the oil chamber with relatively low utilization rate, modify the area in the oil chamber that fails to drain oil in time into a slope structure and / or add an additional oil retaining structure;

[0034] The present invention also provides an optimization system for a turbocharger sealing system based on CFD simulation, comprising:

[0035] A three-dimensional model providing module, for providing a three-dimensional model of a turbocharger sealing system; wherein the three-dimensional model includes an intermediate shell, a compression shell, a volute shell, an oil chamber arranged in the intermediate shell, and a compression impeller located on one side of the oil chamber and arranged in the compression shell and the volute shell respectively, the compression impeller is connected to a rotating shaft arranged in the intermediate shell, the rotating shaft sleeve is provided with a shaft sleeve, and the shaft sleeve sleeve is provided with a sealing ring for isolating the compression end gas and the oil chamber;

[0036] A CFD simulation model building module, used to build a CFD simulation model based on the three-dimensional model;

[0037] A simulation result acquisition module is used to perform a non-steady-state analysis on the CFD simulation model to obtain a simulation result, wherein the simulation result includes a first characteristic parameter of an initial oil leakage section and a second characteristic parameter of an oil leakage surface; wherein the initial oil leakage section is a section at a middle position of the sealing ring closest to the oil leakage outlet, and the oil leakage surface is an end face of the air seal plate close to the impeller wheel back, the first characteristic parameter represents the time taken for the oil volume fraction of the initial oil leakage section to reach a predetermined value for the first time, and the second characteristic parameter represents the total oil leakage of the oil leakage surface in the calculation time domain;

[0038] A reliability analysis module, used for determining the reliability of a turbocharger sealing system according to the first characteristic parameter and the second characteristic parameter;

[0039] The optimization module is used to optimize the CFD simulation model according to the simulation results.

[0040] The above technical solution of the present invention has the following advantages compared with the prior art:

[0041] The turbocharger sealing system optimization method and system based on CFD simulation described in the present invention can clearly compare the performance differences of various design schemes based on the results of CFD simulation analysis, the total amount of oil leakage from the oil leakage surface, the time when the oil volume fraction of the initial oil leakage section first reaches the threshold, and other quantitative indicators, and provide a basis for further optimization, which can effectively guide the optimization design of the sealing system and greatly shorten the product development cycle. It can also provide optimization direction for further improvement of the details inside the sealing system. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to make the contents of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments of the present invention in conjunction with the accompanying drawings.

[0043] Figure 1 It is a flow chart of a turbocharger sealing system optimization method based on CFD simulation of the present invention.

[0044] Figure 2 Schematic diagram of a cross section of a turbocharger in an embodiment of the present invention.

[0045] Figure 3 Schematic diagram of the cross section of the three-dimensional model in the embodiment of the present invention.

[0046] Figure 4 Schematic diagram of the oil domain cavity and the selected computational fluid domain of the sealing system in an embodiment of the present invention.

[0047] Figure 5 It is a schematic diagram of the sealing system of Scheme 1 and Scheme 2 in the embodiments of the present invention.

[0048] Figure 6 It is a schematic diagram of the distribution of oil volume fraction at 10s in Scheme 1 and Scheme 2 in the embodiments of the present invention.

[0049] Figure 7 Schematic diagram of the oil circuit structure in an embodiment of the present invention.

[0050] Figure 8 It is a schematic diagram comparing the oil leakage variation curves over time of Scheme 1 and Scheme 2 in the embodiments of the present invention.

[0051] Fig. 9 It is a comparative diagram of 5% initial oil leakage between Scheme 1 and Scheme 2 in the embodiments of the present invention. DETAILED DESCRIPTION

[0052] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0053] In the present invention, if directions (up, down, left, right, front and back) are described, it is only for the convenience of describing the technical solution of the present invention, and does not indicate or imply that the technical features referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, it cannot be understood as a limitation of the present invention.

[0054] In the present invention, "several" means one or more, "multiple" means more than two, "greater than", "less than", "exceed" and the like are understood to exclude the number itself; "above", "below", "within" and the like are understood to include the number itself. In the description of the present invention, if there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0055] In the present invention, unless otherwise clearly defined, the words "set", "install", "connect" and the like should be understood in a broad sense, for example, they can be directly connected or indirectly connected through an intermediate medium; they can be fixedly connected or detachably connected or integrally formed; they can be mechanically connected or electrically connected or able to communicate with each other; they can be the internal connection of two elements or the interaction relationship between two elements. Those skilled in the art can reasonably determine the specific meanings of the above words in the present invention in combination with the specific content of the technical solution.

[0056] Example 1

[0057] Reference Figure 1 As shown, the present invention is a turbocharger sealing system optimization method based on CFD simulation, the structure of the turbocharger is referenced Figure 2 As shown; the method comprises:

[0058] S1. Provide a 3D model of the turbocharger sealing system, refer to Figure 3 As shown; a three-dimensional geometric model of the sealing system can be established using a three-dimensional modeling tool (such as CATIA, SolidWorks, etc.). The three-dimensional model includes an intermediate housing 100, a compression housing 200, a volute housing 300, an oil chamber 400 disposed in the intermediate housing 100, and a pressure impeller 500 located on one side of the oil chamber 400 and disposed in the compression housing 200 and the volute housing 300, respectively. The pressure impeller 500 is connected to a rotating shaft 600 disposed in the intermediate housing 100, and the rotating shaft 600 is sleeved with a shaft sleeve 700, and the shaft sleeve 700 is sleeved with a sealing ring 800 that separates the pressure end gas and the oil chamber 400.

[0059] It should be noted that the intermediate housing 100, the compression housing 200, and the volute housing 300 are connected in sequence, and an oil circuit is provided on the intermediate housing 100 to lubricate the bearings and other structures installed on the rotating shaft 600, and a plurality of sealing rings 800 are provided on the sleeve 700. In addition, an oil baffle 900 is provided between the oil chamber 400 and the intermediate housing 100. Therefore, referring to Figure 4 As shown, the turbocharger sealing system mainly includes the oil chamber 400, the oil baffle plate 900, the shaft sleeve 700, the sealing ring 800, and the area on the back side (gas seal plate) of the impeller 500. The designs of these components are closely related and directly affect the oil circuit control and sealing performance of the turbocharger sealing system.

[0060] S2. Establish a CFD simulation model based on the three-dimensional model.

[0061] The CFD analysis steps mainly include CFD steady-state initial field calculation based on the sealing system, CFD non-steady-state pre-processing, CFD solver setting, CFD simulation operation, and analysis of CFD simulation results.

[0062] Specifically include:

[0063] extracting a fluid domain of the three-dimensional model;

[0064] Use ICEM CFD in CFX to mesh the fluid domain to obtain a fluid domain mesh model; set the global size of the mesh to 2-4 mm, and 3 mm is used in this embodiment;

[0065] The grid in the oil film area is set as a hexahedral structure grid, and the hexahedral structure grid is perpendicular to the flow direction of the liquid to improve the simulation accuracy;

[0066] For the fluid domain grid model, CFD calculation boundary conditions are set, including the initial steady-state state of the sealing system, the ratio of liquid (oil) and gas (air) in the unsteady process, the liquid surface tension coefficient, the outlet pressure, the gravitational acceleration and the supercharger speed, and the reference pressure.

[0067] S3. Perform a non-steady-state analysis on the CFD simulation model to obtain simulation results, which include a first characteristic parameter of an initial oil leakage section and a second characteristic parameter of an oil leakage surface; wherein the initial oil leakage section is a section at the middle position of the sealing ring 800 closest to the oil leakage outlet, and the oil leakage surface is an end face of the air sealing plate close to the back of the impeller. The first characteristic parameter represents the time taken for the oil volume fraction in the initial oil leakage section to reach a predetermined value for the first time, and the second characteristic parameter represents the total oil leakage of the oil leakage surface in the calculation time domain (simulation time).

[0068] When conducting non-steady-state analysis, it specifically includes:

[0069] Select the unsteady-state calculation model and VOF (Volume of Fluid) model. Unsteady-state CFD simulation can capture the oil leakage behavior of the sealing system under transient conditions, which is particularly important for the dynamic analysis of the sealing system. By calculating the characteristic parameters of the oil leakage section and the oil leakage surface, the oil leakage characteristics of the system can be accurately characterized. The VOF model is used to simulate the behavior of the oil-gas mixture, so that the simulation can handle complex multiphase flow problems and provide more accurate oil leakage assessment results.

[0070] Substitute the CFD calculation boundary conditions into the model equations, set the time step, output parameters of the calculation results and the convergence factor.

[0071] In this embodiment, the output parameter is set to the outlet oil leakage;

[0072] The outlet oil leakage of each step in the time step is obtained, and in the oil leakage surface, the total oil leakage of the oil leakage surface is obtained according to the sum of the total outlet oil leakage in the time step; the time step is set to 5000-8000 steps to ensure that the flow characteristics of the entire sealing system and the occurrence of oil leakage can be captured.

[0073] The time taken for the initial oil leakage section to have an oil volume fraction greater than 4-6% for the first time in the entire time step is obtained.

[0074] For example, the output parameter of the calculation result is the outlet oil leakage m i , (i=1,2,3…s), s is the time selected for the entire calculation, s=8000; then the total oil leakage is

[0075] The unsteady CFD simulation is run through the solver to record the time evolution of the system's initial oil leakage, oil-gas volume ratio, and oil volume accumulation. This simulation result will serve as a comparison benchmark for subsequent optimization solutions.

[0076] S4. Determine the reliability of the turbocharger sealing system according to the first characteristic parameter and the second characteristic parameter. Obtain an oil leakage parameter according to the difference between the second characteristic parameter and the first characteristic parameter. The smaller the oil leakage parameter, the higher the reliability of the turbocharger sealing system.

[0077] The reliability of the turbocharger sealing system is evaluated by the first characteristic parameter (the time when the oil volume fraction in the oil leakage section reaches a predetermined value) and the second characteristic parameter (total oil leakage). The oil leakage risk of the system can be quantitatively evaluated through the values ​​of these two parameters, thereby drawing conclusions about the reliability of the sealing system. The simple parameter (total oil leakage - oil leakage time) provides a reliable basis for subsequent optimization, overcoming the subjectivity and ambiguity of traditional experimental verification.

[0078] S5. Optimizing the CFD simulation model according to the simulation results.

[0079] When the time (first characteristic parameter) taken for the oil volume fraction in the initial oil leakage section to reach a predetermined value for the first time reaches a preset threshold value (e.g., 10s), the structure of the oil cavity 400 is modified according to the utilization and oil discharge conditions of the oil cavity 400, and the CFD simulation model is re-established to obtain an optimized CFD simulation model;

[0080] According to the optimized CFD simulation model, a non-steady-state analysis is performed in the same manner as the CFD simulation model to obtain an optimized simulation result.

[0081] Specifically, according to the utilization and oil discharge conditions of the oil chamber 400, the structure of the oil chamber 400 is modified, including:

[0082] Modify the size of the relatively low utilization area of ​​the oil chamber 400, modify the area in the oil chamber 400 that fails to drain oil in time (from a horizontal plane) to a slope structure and / or add an additional oil retaining structure, refer to Figure 5 shown.

[0083] It should be noted that modifying the size refers to changing the size of some areas inside the oil chamber 400 where the utilization rate is low or there is oil retention. These areas are usually places that are difficult for the oil to reach during the oil throwing process. The oil circuit system is compact in space, and the low-utilization space often occupies the layout of other structures, resulting in low flow efficiency of the lubricating oil in the system and even the risk of oil leakage. By adjusting the size of these areas, the space utilization of the entire oil circuit system can be improved, thereby reducing the risk of oil leakage, and making the flow field in the entire sealing system more uniform, avoiding uneven pressure of local oil, thereby reducing the possibility of oil leakage. For example, inside the oil chamber 400, certain corners or dead corners may cause oil to accumulate and cannot be discharged in time. Modifying the size of these areas can avoid excessive retention of lubricating oil and improve the overall oil drainage capacity of the system.

[0084] The ramp structure refers to an inclined surface designed inside the oil chamber 400, so that the oil can flow more easily along a predetermined path under the guidance of these ramps and finally discharge from the oil chamber 400. The inclination angle of the ramp structure design is usually optimized according to the flow characteristics of the oil to ensure that the oil can flow smoothly under the action of gravity or pressure. By adding a ramp to the oil chamber 400, the oil can be naturally guided to the oil drain port or low-pressure area to avoid the oil from being retained in the oil chamber 400 and reduce the risk of oil leakage. The oil discharge efficiency of the oil chamber 400 is improved, so that the oil in the system can be discharged faster, especially under high-speed conditions of the turbocharger, which can effectively prevent the lubricating oil from being excessively sucked into other areas.

[0085] Adding an oil baffle 900 means adding an additional structure at a key position of the sealing system to prevent the lubricating oil from flowing into the compressor or turbine area by physical blocking. These oil baffles 900 are usually arranged at the transition part of the oil chamber 400 to separate the oil and gas and guide the oil to the correct outlet.

[0086] For example, refer to Figure 5 As shown, the initial CFD simulation model is recorded as Scheme 1. In the steady-state calculation, the model is initialized. Air flows in from the inlet and flows out from the oil outlet and the oil leakage outlet. At this time, the entire calculation domain is filled with air. The boundary conditions are as follows:

[0087] Working medium: air;

[0088] Inlet: flow rate 0.5m / s;

[0089] Oil outlet and oil leakage outlet: atmospheric pressure 1 bar;

[0090] Speed: 1000rad / min;

[0091] In transient calculation, oil flows in from the inlet and flows out from the oil outlet and oil leakage outlet. Since it is filled with air in advance, the entire calculation domain is in an oil-gas mixture state. The boundary conditions are as follows:

[0092] Working fluid: oil;

[0093] Inlet: flow rate 0.1m / s;

[0094] Oil outlet and oil leakage outlet: atmospheric pressure 1 bar;

[0095] Rotation speed: 1000rad / min.

[0096] At the beginning of transient calculation, the inlet boundary is the oil flow rate. If the oil volume fraction detected at the outlet of the oil leakage surface is greater than 5%, it is confirmed to be an oil leakage state, and the oil leakage volume within 8000s is counted.

[0097] Reference Figures 6 to 9 As shown, it can be seen that the initial oil leakage of the oil leakage outlet surface of Scheme 1 reaches more than 5% at 10s. According to the distribution of the oil volume fraction of Scheme 1 at 10s, it is found that the utilization rate of the oil chamber 400 is not high and there are areas where the oil cannot be discharged in time. The structure of the oil chamber 400 here is modified (the utilization rate of the oil chamber 400 is not high, and the area where the oil cannot be discharged in time is modified to a slope structure), and an additional oil blocking structure is added. Scheme 2 is formed.

[0098] Let the value of the first characteristic parameter be T, and the value of the second characteristic parameter be M, and the oil leakage parameter P=MT is calculated. The smaller the P value is, the lower the risk of oil leakage is, and the higher the corresponding reliability of the supercharger is.

[0099] By performing transient calculation on Scheme 2, refer to Figure 8 , Fig. 9 As shown in the figure, no leakage volume fraction greater than 5% was detected at the oil leakage outlet surface at 10s. The comparison table is shown below.

[0100] Table 1: Comparison between Scheme 1 and Scheme 2

[0101]

[0102] It can be seen that the optimized system significantly reduces the probability of oil leakage and ensures the long-term stable operation of the turbocharger. Through CFD simulation analysis, the oil leakage of the sealing system can be accurately predicted. The use of non-steady-state analysis models (such as VOF models) can better simulate the behavior of the oil-gas mixture, thereby more accurately judging the reliability of the sealing system. The oil leakage risk of the sealing system can be quantified by analyzing the oil volume fraction of the initial oil leakage section and the total oil leakage on the oil leakage surface.

[0103] Example 2

[0104] Based on the same inventive concept, this embodiment provides an optimization system for a turbocharger sealing system based on CFD simulation. The principle of solving the problem is similar to the turbocharger sealing system optimization method based on CFD simulation, and the repeated parts are not repeated here.

[0105] This embodiment provides an optimization system for a turbocharger sealing system based on CFD simulation, comprising:

[0106] A three-dimensional model providing module, for providing a three-dimensional model of a turbocharger sealing system; wherein the three-dimensional model includes an intermediate housing 100, a compression housing 200, a volute housing 300, an oil chamber 400 disposed in the intermediate housing 100, and a compression impeller 500 located on one side of the oil chamber 400 and disposed in the compression housing 200 and the volute housing 300, respectively, the compression impeller 500 is connected to a rotating shaft 600 disposed in the intermediate housing 100, the rotating shaft 600 is sleeved with a shaft sleeve 700, and the shaft sleeve 700 is sleeved with a sealing ring 800 for isolating the compression end gas and the oil chamber 400;

[0107] A CFD simulation model building module, used to build a CFD simulation model based on the three-dimensional model;

[0108] A simulation result acquisition module, used for performing a non-steady-state analysis on the CFD simulation model to obtain a simulation result, wherein the simulation result includes a first characteristic parameter of an initial oil leakage section and a second characteristic parameter of an oil leakage surface; wherein the initial oil leakage section is a section at a middle position of the sealing ring 800 closest to the oil leakage outlet, and the oil leakage surface is an end face of the air seal plate close to the impeller wheel back, the first characteristic parameter represents the time taken for the oil volume fraction of the initial oil leakage section to reach a predetermined value for the first time, and the second characteristic parameter represents the total oil leakage of the oil leakage surface in the calculation time domain;

[0109] A reliability analysis module, used for determining the reliability of a turbocharger sealing system according to the first characteristic parameter and the second characteristic parameter;

[0110] The optimization module is used to optimize the CFD simulation model according to the simulation results.

[0111] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0112] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0113] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0114] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0115] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A turbocharger sealing system optimization method based on CFD simulation, characterized in that: include: A three-dimensional model of a turbocharger sealing system is provided; wherein the three-dimensional model comprises an intermediate housing, a compression housing, a volute housing, an oil chamber arranged in the intermediate housing, and a compression impeller located on one side of the oil chamber and arranged in the compression housing and the volute housing respectively, the compression impeller being connected to a rotating shaft arranged in the intermediate housing, the rotating shaft sleeve being provided with a shaft sleeve, and the shaft sleeve sleeve being provided with a sealing ring for isolating the compression end gas and the oil chamber; Based on the three-dimensional model, a CFD simulation model is established; Performing a non-steady-state analysis on the CFD simulation model to obtain simulation results, the simulation results including a first characteristic parameter of an initial oil leakage section and a second characteristic parameter of an oil leakage surface; wherein the initial oil leakage section is a section at a middle position of the sealing ring closest to the oil leakage outlet, the oil leakage surface is an end surface of the air seal plate close to the impeller wheel back, the first characteristic parameter characterizes the time taken for the oil volume fraction in the initial oil leakage section to reach a predetermined value for the first time, and the second characteristic parameter characterizes the total oil leakage of the oil leakage surface in a calculated time domain; judging the reliability of a turbocharger sealing system according to the first characteristic parameter and the second characteristic parameter; According to the simulation results, the CFD simulation model is optimized.

2. The turbocharger sealing system optimization method based on CFD simulation according to claim 1, characterized in that: Based on the three-dimensional model, a CFD simulation model is established, including: extracting a fluid domain of the three-dimensional model; Meshing the fluid domain to obtain a fluid domain mesh model; For the fluid domain grid model, CFD calculation boundary conditions are set.

3. The turbocharger sealing system optimization method based on CFD simulation according to claim 2 is characterized in that: The fluid domain is meshed to obtain a fluid domain mesh model, including: Set the global size of the grid to 2-4mm; The grid in the oil film region is set as a hexahedral structure grid, and the hexahedral structure grid is perpendicular to the flow direction of the liquid.

4. The turbocharger sealing system optimization method based on CFD simulation according to claim 2, characterized in that: The CFD calculation boundary conditions include the initial steady-state state of the sealing system, the ratio of liquid to gas in the unsteady-state process, the liquid surface tension coefficient, the outlet pressure, the gravity acceleration and the supercharger speed, and the reference pressure.

5. The turbocharger sealing system optimization method based on CFD simulation according to claim 2, characterized in that: Performing a non-steady-state analysis on the CFD simulation model includes: Select the unsteady-state calculation model and VOF model; Substitute the CFD calculation boundary conditions into the model equations, set the time step, output parameters of the calculation results and the convergence factor.

6. The turbocharger sealing system optimization method based on CFD simulation according to claim 5, characterized in that: The method further comprises: The output parameter is set to the outlet oil leakage; Obtain the oil leakage amount of the outlet in each step of the time step, and in the oil leakage surface, obtain the total oil leakage amount of the oil leakage surface according to the sum of the total oil leakage amount of the outlet in the time step; the time step is set to 5000-8000 steps; The time taken for the initial oil leakage section to have an oil volume fraction greater than 4-6% for the first time in the entire timing step is obtained.

7. The turbocharger sealing system optimization method based on CFD simulation according to claim 1, characterized in that: Judging the reliability of the turbocharger sealing system according to the first characteristic parameter and the second characteristic parameter includes: An oil leakage parameter is obtained according to the difference between the values ​​of the second characteristic parameter and the first characteristic parameter. The smaller the oil leakage parameter is, the higher the reliability of the supercharger sealing system is.

8. The turbocharger sealing system optimization method based on CFD simulation according to claim 1, characterized in that: According to the simulation results, the CFD simulation model is optimized, including: When the first characteristic parameter reaches a preset threshold, the structure of the oil cavity is modified according to the space utilization and oil drainage of the oil cavity, and the CFD simulation model is re-established to obtain an optimized CFD simulation model; According to the optimized CFD simulation model, a non-steady-state analysis is performed in the same manner as the CFD simulation model to obtain an optimized simulation result.

9. The turbocharger sealing system optimization method based on CFD simulation according to claim 1, characterized in that: According to the utilization and oil discharge conditions of the oil chamber, the structure of the oil chamber is modified, including: Modify the size of the oil chamber with relatively low utilization rate, modify the area in the oil chamber that fails to drain oil in time into a slope structure and / or add an additional oil retaining structure.

10. An optimization system for a turbocharger sealing system based on CFD simulation, characterized in that: include: A three-dimensional model providing module, for providing a three-dimensional model of a turbocharger sealing system; wherein the three-dimensional model includes an intermediate shell, a compression shell, a volute shell, an oil chamber arranged in the intermediate shell, and a compression impeller located on one side of the oil chamber and arranged in the compression shell and the volute shell respectively, the compression impeller is connected to a rotating shaft arranged in the intermediate shell, the rotating shaft sleeve is provided with a shaft sleeve, and the shaft sleeve sleeve is provided with a sealing ring for isolating the compression end gas and the oil chamber; A CFD simulation model building module, used to build a CFD simulation model based on the three-dimensional model; A simulation result acquisition module is used to perform a non-steady-state analysis on the CFD simulation model to obtain a simulation result, wherein the simulation result includes a first characteristic parameter of an initial oil leakage section and a second characteristic parameter of an oil leakage surface; wherein the initial oil leakage section is a section at a middle position of the sealing ring closest to the oil leakage outlet, and the oil leakage surface is an end face of the air seal plate close to the impeller wheel back, the first characteristic parameter represents the time taken for the oil volume fraction of the initial oil leakage section to reach a predetermined value for the first time, and the second characteristic parameter represents the total oil leakage of the oil leakage surface in the calculation time domain; A reliability analysis module, used for determining the reliability of a turbocharger sealing system according to the first characteristic parameter and the second characteristic parameter; The optimization module is used to optimize the CFD simulation model according to the simulation results.

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