Simulation method of separation efficiency of oil-gas separator

Abstract

The present invention discloses a method for simulating the separation efficiency of an oil-gas separator, and belongs to the technical field of oil-gas separators. The method for simulating the separation efficiency of an oil-gas separator comprises S1, constructing a three-dimensional fluid domain model of the oil-water separator according to the mechanism parameters of the oil-water separator; S2, performing finite element meshing on the three-dimensional fluid domain model, wherein no boundary layer mesh is set for the laminated wall surface of the three-dimensional fluid domain model; S3, setting boundary conditions, and performing simulation solution calculation. The method can improve the accuracy of the simulation calculation results of the separation efficiency of the oil-water separator, and is helpful to improve the structure and performance of the oil-gas separator.

Description

Technical Field

[0001] The invention relates to the technical field of oil-water separators, and in particular to a method for simulating separation efficiency of an oil-gas separator. Background Art

[0002] The automotive oil-gas separator is a key component in the crankcase emission system of the automotive engine. The automotive oil-gas separator needs to separate the oil mist from the gas mixed with oil mist. The separation principle is to perform physical separation through the structural characteristics of the product (such as laminations). The gas mixed with oil mist enters the special structure of the product and is in a high-speed motion process. The centrifugal force generated by the high speed will throw the oil mist out and stick to the inner wall of the product. As time accumulates, the oil mist on the inner wall turns into oil droplets, and the oil droplets turn into oil film. The oil film then forms a flowing stream and flows into the storage cavity, and finally discharges the excess useless oil.

[0003] At present, the oil-gas separator separation efficiency simulation experiment is generally carried out in the simulation laboratory to calculate the oil-gas separator separation efficiency, and the structure obtained by the experiment is used to improve the structure and performance of the oil-gas separator. However, the experimental results obtained by the existing fluid simulation modeling method are greatly different from the actual situation, which is not conducive to the improvement of the oil-gas separator structure and performance.

[0004] Therefore, it is urgent to provide a method for simulating the separation efficiency of an oil-gas separator to solve the above problems. Summary of the invention

[0005] The purpose of the present invention is to provide a method for simulating the separation efficiency of an oil-gas separator, which can improve the accuracy of simulation calculation results of the separation efficiency of the oil-water separator and contribute to the improvement of the structure and performance of the oil-gas separator.

[0006] In order to achieve the above objectives, the following technical solutions are provided:

[0007] The oil-gas separator separation efficiency simulation method includes:

[0008] S1. constructing a three-dimensional fluid domain model of the oil-water separator according to the mechanism parameters of the oil-water separator;

[0009] S2, performing finite element meshing on the three-dimensional fluid domain model, wherein no boundary layer mesh is set on the laminated wall surface of the three-dimensional fluid domain model;

[0010] S3. Set boundary conditions and perform simulation calculations.

[0011] As an optional solution of the oil-gas separator separation efficiency simulation method, the oil-water separator includes:

[0012] The shell has a separation cavity, and a plurality of the laminates are sequentially stacked and arranged in the separation cavity along a first direction;

[0013] An air inlet pipe, an air outlet of the air inlet pipe is connected to the shell and communicated with the separation chamber, and the air inlet of the air inlet pipe is used to introduce oil mist;

[0014] An air outlet pipe, an air inlet of which is connected to the shell and communicates with the separation chamber;

[0015] A base, arranged at the bottom of the shell, the base having an oil collecting cavity, the oil collecting cavity being communicated with the separation cavity;

[0016] An oil drain pipe, wherein an oil inlet of the oil drain pipe is connected to the base and communicated with the oil collecting cavity.

[0017] As an optional solution of the method for simulating the separation efficiency of an oil-gas separator, the air outlet of the air outlet pipe corresponding to the three-dimensional fluid domain model is used as a simulation solution calculation area.

[0018] As an optional solution of the oil-gas separator separation efficiency simulation method, in step S1, the inner diameter of the intake pipe is D1, and the intake pipe is stretched to a length of 6×D1.

[0019] As an optional solution of the oil-gas separator separation efficiency simulation method, in step S1, the inner diameter of the outlet pipe is D2, and the outlet pipe is stretched to a length of 4×D2.

[0020] As an optional solution of the oil-gas separator separation efficiency simulation method, in step S2, finite element meshing is performed on the shell of the oil-water separator in the three-dimensional fluid domain model.

[0021] As an optional solution to the oil-gas separator separation efficiency simulation method, the wall surface of the shell is divided into boundary layer grids.

[0022] As an optional solution of the oil-gas separator separation efficiency simulation method, the number of layers of the boundary layer grid is 2-5, and the gradient rate of the boundary layer grid is 1.2-1.5.

[0023] As an optional solution of the oil-gas separator separation efficiency simulation method, in step S2 and step S3, a wall normal compensation coefficient and a wall tangential compensation coefficient are set for the shell.

[0024] As an optional solution of the separation efficiency simulation method of the oil-gas separator, the tangential compensation coefficient of the wall of the shell is 0.3-0.4, and the normal compensation coefficient of the wall of the shell is 0.6-0.7.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The method for simulating the separation efficiency of an oil-gas separator provided by the present invention constructs a three-dimensional fluid domain model of the oil-water separator according to the structural parameters of the oil-water separator, performs finite element meshing on the three-dimensional fluid domain model, wherein no boundary layer mesh is set for the laminated wall surface of the three-dimensional fluid domain model, boundary conditions are set, and simulation solution calculations are performed. This method cancels the setting of the internal laminated boundary layer of the three-dimensional fluid domain model of the oil-water separator. After the oil mist enters the oil-gas separator, because the mass of the oil mist itself is small enough, it will be driven by the laminated plate and the radial component force. Under the action of these two forces, the oil mist will spirally move along the inner wall of the oil-gas separator. The purpose of canceling the boundary layer is to eliminate the influence of the boundary layer on the micro-oil mist, so that the simulation is as close to the actual working condition as possible and the simulation accuracy is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the contents of the embodiments of the present invention and these drawings without paying any creative work.

[0028] Figure 1 Flow chart of a method for simulating separation efficiency of an oil-gas separator in an embodiment of the present invention;

[0029] Figure 2 It is a structural schematic diagram of an oil-gas separator in an embodiment of the present invention;

[0030] Figure 3 A top view of an oil-gas separator in an embodiment of the present invention;

[0031] Figure 4 for Figure 3 Sectional view along AA direction;

[0032] Figure 5 for Figure 3 Cross-sectional view along the BB axis.

[0033] Reference numerals:

[0034] 1. Shell; 2. Laminations; 3. Inlet pipe; 4. Outlet pipe; 5. Base; 6. Oil drain pipe. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0036] In the description of the present invention, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or are the positions or positional relationships in which the inventive product is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0037] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "disposed" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0039] In order to improve the accuracy of the simulation calculation results of the oil-water separator separation efficiency and help improve the structure and performance of the oil-gas separator, this embodiment provides a simulation method for the oil-gas separator separation efficiency. Figures 1 to 5 The specific contents of this embodiment are described in detail. It should be noted that the first direction mentioned in this embodiment is Figure 4 The Z direction in .

[0040] The oil-gas separator separation efficiency simulation method in this embodiment includes: S1, constructing a three-dimensional fluid domain model of the oil-water separator according to the structural parameters of the oil-water separator; S2, performing finite element meshing on the three-dimensional fluid domain model, wherein no boundary layer mesh is set on the wall surface of the stack 2 of the three-dimensional fluid domain model; S3, setting boundary conditions and performing simulation solution calculations.

[0041] In short, the oil-gas separator separation efficiency simulation method provided by the present invention constructs a three-dimensional fluid domain model of the oil-water separator according to the structural parameters of the oil-water separator, performs finite element meshing on the three-dimensional fluid domain model, wherein no boundary layer mesh is set on the wall surface of the laminate 2 of the three-dimensional fluid domain model, sets boundary conditions, and performs simulation solution calculations. This method cancels the setting of the boundary layer of the laminate 2 inside the three-dimensional fluid domain model of the oil-water separator. After the oil mist enters the oil-gas separator, because the mass of the oil mist itself is small enough, it will be driven by the laminate 2 and subjected to centrifugal force and radial force. Under the action of these two forces, the oil mist will spiral along the inner wall of the oil-gas separator. The purpose of canceling the boundary layer is to eliminate the influence of the boundary layer on the micro-oil mist, so that the simulation is as close to the actual working condition as possible and the simulation accuracy is improved.

[0042] Furthermore, a three-dimensional fluid domain model of the oil-water separator is constructed according to the structural parameters of the oil-water separator as follows: the oil-water separator includes a shell 1, an air inlet pipe 3, an air outlet pipe 4, a base 5 and an oil drain pipe 6. The shell 1 has a separation cavity, and a plurality of laminations 2 are stacked in sequence along a first direction in the separation cavity. The air outlet of the air inlet pipe 3 is connected to the shell 1 and communicated with the separation cavity, and the air inlet of the air inlet pipe 3 is used to introduce oil mist. The air inlet of the air outlet pipe 4 is connected to the shell 1 and communicated with the separation cavity. The base 5 is arranged at the bottom of the shell 1, and the base 5 has an oil collecting cavity, which is communicated with the separation cavity, and the oil collecting cavity is used to collect separated oil. The oil inlet of the oil drain pipe 6 is connected to the base 5 and communicated with the oil collecting cavity.

[0043] When in use, the oil mist enters the housing 1 from the air inlet pipe 3 and rotates under the guidance and stirring of the rotating stack 2, so that the oil in the oil mist is thrown toward the inner wall of the housing 1 under the action of centrifugal force, and then flows to the collection chamber of the base 5 and is discharged from the oil drain pipe 6, and the clean air is discharged outward through the outlet of the air outlet pipe 4.

[0044] Furthermore, the outlet of the outlet pipe 4 corresponding to the three-dimensional fluid domain model is used as the simulation solution calculation area. The oil mist enters the oil-gas separator with the air, and most of the oil will be absorbed by the storage structure (oil collecting cavity). The statistical method of oil-gas separation efficiency in the industry is: Oil-gas separation efficiency = (mass flow rate of oil captured by the wall of the oil collecting cavity ÷ mass flow rate of oil mist at the inlet of the intake pipe) × 100%. Because a part of the oil mist will remain on the inner wall of the product and the wall of the laminate 2, this method will cause a large deviation between the simulation results and the actual results. In order to eliminate this deviation, the statistical surface of the oil mass flow rate is adjusted, and the specific surface of the outlet of the outlet pipe 4 is selected as the capture surface of the oil mist for the oil-gas separation efficiency calculation method: Oil-gas separation efficiency = 1-(mass flow rate of oil mist captured at the outlet of the outlet pipe ÷ mass flow rate of oil mist at the inlet of the intake pipe) × 100%.

[0045] Furthermore, in step S1, the inner diameter of the air inlet pipe 3 is D1, and the air inlet pipe 3 is stretched to a length of 6×D1. Furthermore, the inner diameter of the air outlet pipe 4 is D2, and the air outlet pipe 4 is stretched to a length of 4×D2. That is, the stretched length of the air inlet pipe 3 is 6 times its inner diameter, and the stretched length of the air outlet pipe 4 is 4 times its inner diameter, so that the simulation effect is closer to the actual use (such as the actual external connection air pipe). The stretching type selects the gradient mesh type in order to improve the calculation stability, save calculation time and improve the calculation efficiency.

[0046] For example, the value of the inner diameter D1 of the air inlet pipe 3 and the value of the inner diameter D2 of the air outlet pipe 4 may be the same or different, and no further limitation is made here.

[0047] Further, in step S2, the shell 1 of the oil-water separator in the three-dimensional fluid domain model is divided into finite element meshes. The finite element meshes are divided into zones according to the characteristics of the fluid domain of the oil-water separator, and different mesh types and mesh parameters can be used in different areas to make the simulation solution more accurate.

[0048] Specifically, the shell 1 of the oil-water separator is divided in sequence from the air inlet pipe 3 to the air outlet pipe 4. In this embodiment, since the fluid domain movement law of the shell 1 is complex, the grid of the shell 1 can be encrypted.

[0049] Furthermore, the wall of the shell 1 is divided into boundary layer grids. In this embodiment, since the main collision area of ​​the oil mist is the wall of the laminate 2, the method of not setting the boundary layer grid on the wall of the laminate 2 is to eliminate the error caused by the oil mist particles hitting the wall of the laminate 2 driven by the flow field, thereby ensuring the flow resistance accuracy and improving the accuracy of the simulation calculation results of the separation efficiency. In addition, the boundary layer is a thin flow layer in the high Reynolds number flow close to the surface of the object, and the viscosity force cannot be ignored. It is also called the flow boundary layer or the boundary layer. The flow medium close to the boundary layer has a velocity close to zero, and the flow medium outside the boundary layer can basically be regarded as inviscid, which is the mainstream area. In this way, there must be a normal velocity gradient in the fluid domain at the boundary layer. Due to the existence of this gradient, the presence or absence of a boundary layer will have a relatively large impact on the flow resistance of the calculated flow field. The setting of the boundary layer grid on the wall of the shell 1 can further improve the accuracy of the simulation calculation results of the separation efficiency.

[0050] Further, the number of layers of the boundary layer grid is 2-5, and the gradient rate of the boundary layer grid is 1.2-1.5. Optionally, the number of layers of the boundary layer grid can be but not limited to 2, 3, 4 or 5, and the gradient rate of the boundary layer grid can be but not limited to 1.2, 1.3, 1.4 or 1.5.

[0051] Furthermore, in step S2 and step S3, a wall normal compensation coefficient and a wall tangent compensation coefficient are set for the shell 1. In the process of finite element meshing of the three-dimensional fluid domain model, when the particles pass through a position with a large structural difference in the three-dimensional fluid domain model, the particles and the wall of the three-dimensional fluid domain model have different collision angles, which will produce energy loss errors. By setting the wall normal compensation coefficient and the wall tangent compensation coefficient for the shell 1 as compensation, the accuracy of the simulation calculation results of the separation efficiency can be improved.

[0052] For example, the tangential compensation coefficient of the wall of the shell 1 is 0.3-0.4, and the normal compensation coefficient of the wall of the shell 1 is 0.6-0.7, so as to further improve the accuracy of the simulation calculation results of the separation efficiency.

[0053] Specifically, the separation efficiency simulation method of the oil-gas separator can be completed by CAE simulation software or other simulation software, which will not be described in detail here. This simulation technology (optimization modeling) greatly improves the simulation accuracy.

[0054] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A method for simulating separation efficiency of an oil-gas separator, characterized in that: include: S1. constructing a three-dimensional fluid domain model of the oil-water separator according to the mechanism parameters of the oil-water separator; S2, performing finite element meshing on the three-dimensional fluid domain model, wherein no boundary layer mesh is provided on the wall surface of the laminate (2) of the three-dimensional fluid domain model; S3. Set boundary conditions and perform simulation calculations.

2. The oil-gas separator separation efficiency simulation method according to claim 1, characterized in that: The oil-water separator comprises: The housing (1) has a separation cavity, and a plurality of the laminated sheets (2) are stacked in sequence along a first direction and arranged in the separation cavity; An air inlet pipe (3), an air outlet of the air inlet pipe (3) being connected to the housing (1) and communicating with the separation chamber, and the air inlet of the air inlet pipe (3) being used for introducing oil mist; An air outlet pipe (4), an air inlet of the air outlet pipe (4) being connected to the shell (1) and communicating with the separation chamber; A base (5) is arranged at the bottom of the housing (1), the base (5) having an oil collecting cavity, the oil collecting cavity being in communication with the separation cavity; An oil drain pipe (6), wherein an oil inlet of the oil drain pipe (6) is connected to the base (5) and communicates with the oil collecting cavity.

3. The oil-gas separator separation efficiency simulation method according to claim 2, characterized in that: The air outlet of the air outlet pipe (4) corresponding to the three-dimensional fluid domain model is used as a simulation solution calculation area.

4. The oil-gas separator separation efficiency simulation method according to claim 3, characterized in that: In step S1, the inner diameter of the air intake pipe (3) is D1, and the air intake pipe (3) is stretched to a length of 6×D1.

5. The oil-gas separator separation efficiency simulation method according to claim 4, characterized in that: In step S1, the inner diameter of the air outlet pipe (4) is D2, and the air outlet pipe (4) is stretched to a length of 4×D2.

6. The oil-gas separator separation efficiency simulation method according to claim 3, characterized in that: In step S2, finite element meshing is performed on the shell (1) of the oil-water separator in the three-dimensional fluid domain model.

7. The oil-gas separator separation efficiency simulation method according to claim 6, characterized in that: The wall surface of the shell (1) is divided into boundary layer grids.

8. The oil-gas separator separation efficiency simulation method according to claim 7, characterized in that: The number of layers of the boundary layer grid is 2-5, and the gradient rate of the boundary layer grid is 1.2-1.

5.

9. The method for simulating separation efficiency of an oil-gas separator according to claim 6, characterized in that: In step S2 and step S3, a wall normal compensation coefficient and a wall tangential compensation coefficient are set for the shell (1).

10. The oil-gas separator separation efficiency simulation method according to claim 9, characterized in that: The tangential compensation coefficient of the wall surface of the shell (1) is 0.3-0.4, and the normal compensation coefficient of the wall surface of the shell (1) is 0.6-0.7.

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