Simulation statistical method for filtering efficiency of prefilter

Abstract

The invention discloses a simulation statistical method for filtering efficiency of a prefilter, and belongs to the technical field of filters. The pre-filter filtration efficiency simulation statistical method comprises the following steps: S1, constructing a three-dimensional fluid domain model of a rotational flow filtration component according to mechanism parameters of the rotational flow filtration component of a pre-filter; s2, performing finite element grid division on the rotational flow filtering component, wherein boundary layer grids are not set on the wall surfaces of rotational flow blades in the rotational flow filtering component; and S3, taking the full wall surface of the dust existence area in the cyclone filtering part as a simulation solution calculation area. According to the method, errors generated by space and calculation iteration can be directly eliminated, and the statistical accuracy of the rough filtration efficiency of the prefilter is improved.

Description

Technical Field

[0001] The invention relates to the technical field of filters, and in particular to a simulation statistical method for filtering efficiency of a pre-filter. Background Art

[0002] A pre-filter is a preliminary filter in a filtration system that is used to remove large particles or contaminants from a fluid before formal filtration. The pre-filter is designed to remove most of the large particles before subsequent fine filtration, thereby reducing the burden on the fine filter and extending its service life.

[0003] Among them, the air pre-filter is used to filter out dust particles in the air and has a large dust holding capacity. It is usually installed on the air inlet pipe and used in conjunction with the fine filter and gas filter.

[0004] At present, the cyclone type pre-filter uses the ash discharge port as the statistical basis, and the coarse filtration efficiency of the pre-filter = (ash discharge port dust mass flow rate ÷ inlet dust mass flow rate) × 100%. On the one hand, some dust particles will flow in the annular surface where the ash discharge port is located and cannot enter the ash discharge port, which will cause a large calculation error; on the other hand, since there are dozens of cyclone tubes in the fluid domain where the cyclone tube is located, when dust enters this complex internal flow field, some particles will be unable to enter the dust discharge port through iterative calculation, which will further amplify the calculation error.

[0005] Therefore, it is urgent to provide a pre-filter filtration efficiency simulation statistical method to solve the above problems. Summary of the invention

[0006] The object of the present invention is to provide a pre-filter filtration efficiency simulation statistical method, which can directly eliminate the errors caused by space and calculation iterations and improve the statistical accuracy of the coarse filtration efficiency of the pre-filter.

[0007] In order to achieve the above objectives, the following technical solutions are provided:

[0008] The pre-filter filtration efficiency simulation statistical method comprises the following steps:

[0009] S1. constructing a three-dimensional fluid domain model of the cyclone filter component according to the mechanism parameters of the cyclone filter component of the pre-filter;

[0010] S2, performing finite element mesh division on the cyclone filter component, wherein the wall surface of the cyclone blades in the cyclone filter component is not set with a boundary layer mesh;

[0011] S3, taking the entire wall surface of the dust existing area in the cyclone filter component as the simulation solution calculation area.

[0012] As an optional solution for the statistical method of pre-filter filtration efficiency simulation, the cyclone filter component includes:

[0013] A housing having an installation chamber and a dust collecting chamber which are interconnected, wherein the dust collecting chamber has a dust exhaust port;

[0014] A plurality of swirl tubes are arranged in the installation chamber, swirl blades are arranged in the swirl tubes, and a dust discharge port is arranged on one side of the swirl tubes close to the dust collecting chamber.

[0015] As an optional solution of the pre-filter filtration efficiency simulation statistical method, the pre-filter further includes:

[0016] An air inlet component, which is arranged on the air inlet side of the shell and is sealed and connected to the shell;

[0017] An air outlet component is arranged on the air outlet side of the shell and is sealed and connected to the shell.

[0018] As an optional scheme for the statistical method of simulating the filtration efficiency of the pre-filter, in step S2, the three-dimensional fluid domain model of the vortex tube is divided into a first non-impeller tube segment, an impeller tube segment and a second non-impeller tube segment according to the structure of the vortex tube, and finite element mesh division is performed on the first non-impeller tube segment, the impeller tube segment and the second non-impeller tube segment, respectively, wherein the vortex blade is located in the impeller tube segment.

[0019] As an optional scheme of the statistical method for simulating the filtration efficiency of the pre-filter, in step S2, the non-swirl blade wall of the impeller pipe segment, the first non-impeller pipe segment wall and the second non-impeller pipe segment wall are divided into boundary layer grids.

[0020] As an optional solution of the statistical method for simulating the filtration efficiency of the pre-filter, in step S2, the number of layers of the boundary layer grid is 2-5.

[0021] As an optional solution of the statistical method for simulating the filtration efficiency of the pre-filter, in step S2, the gradient rate of the boundary layer grid is 1.2-1.5.

[0022] As an optional scheme for the statistical method of simulating the filtration efficiency of the pre-filter, the following steps are also included between step S2 and step S3: setting the wall normal compensation coefficient and the wall tangential compensation coefficient for the first non-impeller pipe section, the impeller pipe section and the second non-impeller pipe section.

[0023] As an optional scheme for the statistical method of simulating the filtration efficiency of the pre-filter, the tangential compensation coefficients of the wall of the first non-impeller pipe section and the second non-impeller pipe section are both 0.8-0.89, and the normal compensation coefficients of the wall of the first non-impeller pipe section and the second non-impeller pipe section are both 0.6-0.69.

[0024] As an optional scheme for the statistical method of simulating the filtration efficiency of the pre-filter, the tangential compensation coefficient of the wall surface of the impeller pipe section is 0.3-0.4; the normal compensation coefficient of the wall surface of the impeller pipe section is 0.4-0.5.

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

[0026] The simulation statistical method for the filtration efficiency of the pre-filter provided by the present invention, in the process of simulating and solving the coarse filtration efficiency, the collision of solid particles with the boundary layer will be distorted, because the main collision area of ​​solid particles is the wall of the swirl blade. In the process of finite element meshing of the three-dimensional fluid domain model, the method of not setting the boundary layer mesh on the wall of the swirl blade is used to eliminate the error caused by the distortion of solid particles hitting the wall of the swirl blade driven by the flow field, thereby ensuring the flow resistance accuracy and improving the accuracy of the simulation calculation results of the coarse filtration efficiency. The statistical method for the dust filtration efficiency of the pre-filter is the full wall statistical method of the dust existing area in the swirl filter component. The full wall dust capture statistical method is used to replace the original method of using the dust discharge port as the statistical basis. The method for calculating the coarse filtration efficiency after optimization is coarse filtration efficiency = (mass flow rate of dust captured by the full wall of the swirl filter component ÷ mass flow rate of dust at the inlet of the air inlet component) × 100%. The simulation statistical method for the filtration efficiency of the pre-filter eliminates the error generated by using the dust discharge port as the statistical basis for the coarse filtration efficiency statistics, which can directly eliminate the errors generated by space and calculation iterations, and improve the statistical accuracy of the coarse filtration efficiency of the pre-filter. 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 It is a flow chart of the simulation statistical method of the filtration efficiency of the pre-filter in the embodiment of the present invention;

[0029] Figure 2 This is a schematic diagram of the assembly of a pre-filter in an embodiment of the present invention;

[0030] Figure 3 An explosion schematic diagram of a pre-filter in an embodiment of the present invention;

[0031] Figure 4 is a cross-sectional view of a pre-filter in an embodiment of the present invention;

[0032] Figure 5 This is a schematic diagram of the structure of a cyclone tube in an embodiment of the present invention;

[0033] Figure 6 4 is a cross-sectional view of a cyclone tube in an embodiment of the present invention.

[0034] Reference numerals:

[0035] 1. Cyclone filter component; 2. Air inlet component; 3. Air outlet component; 31. Air outlet pipe;

[0036] 11. Shell; 111. Installation chamber; 112. Dust collecting chamber; 1121. Dust discharge port; 12. Swirl pipe; 121. Swirl blades; 122. Dust discharge port; 123. First non-impeller pipe section; 124. Impeller pipe section; 125. Second non-impeller pipe section. DETAILED DESCRIPTION

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] In order to directly eliminate the errors caused by space and calculation iteration, this embodiment provides a pre-filter filtration efficiency simulation statistical method. Figures 1 to 6 The specific contents of this embodiment are described in detail.

[0042] The statistical method for simulating the filtration efficiency of the pre-filter in this embodiment includes the following steps: S1. Constructing a three-dimensional fluid domain model of the cyclone filter component 1 according to the structural parameters of the cyclone filter component 1 of the pre-filter; S2. Performing finite element meshing on the cyclone filter component 1, wherein the wall surface of the cyclone blades 121 in the cyclone filter component 1 does not set a boundary layer mesh; S3. Using the entire wall surface of the dust existence area in the cyclone filter component 1 as the simulation solution calculation area.

[0043] In short, the simulation statistical method of the filtration efficiency of the pre-filter provided by the present invention is distorted when solid particles collide with the boundary layer during the simulation solution of the coarse filtration efficiency. Since the main collision area of ​​the solid particles is the wall of the swirl blade 121, in the process of finite element meshing of the three-dimensional fluid domain model, the error caused by the distortion of the solid particles hitting the wall of the swirl blade 121 driven by the flow field is eliminated by not setting the boundary layer mesh on the wall of the swirl blade 121, thereby ensuring the flow resistance accuracy and improving the accuracy of the simulation calculation results of the coarse filtration efficiency. The statistical method of dust filtration efficiency of the pre-filter is the full wall statistical method of the dust existing area in the swirl filter component 1. The full wall dust capture statistical method is used to replace the original method of using the dust outlet 122 as the statistical basis. The method of calculating the coarse filtration efficiency after optimization is coarse filtration efficiency = (mass flow rate of dust captured by the full wall of the swirl filter component 1 ÷ mass flow rate of dust at the inlet of the air inlet component 2) × 100%. The pre-filter filtration efficiency simulation statistical method eliminates the error generated by taking the ash discharge port 122 as the statistical basis for the coarse filtration efficiency statistics, can directly eliminate the error generated by space and calculation iteration, and improve the statistical accuracy of the coarse filtration efficiency of the pre-filter.

[0044] like Figures 3 to 5 As shown, further, the three-dimensional fluid domain model of the cyclone filter component 1 is constructed according to the mechanism parameters of the cyclone filter component 1 of the pre-filter as follows: the cyclone filter component 1 includes a shell 11 and a plurality of cyclone tubes 12, wherein the shell 11 has an installation chamber 111 and a dust collecting chamber 112 which are interconnected, and the dust collecting chamber 112 has a dust discharge port 1121. A plurality of cyclone tubes 12 are arranged in the installation chamber 111, and a cyclone blade 121 is arranged in the cyclone tube 12, and a dust discharge port 122 is arranged on one side of the cyclone tube 12 close to the dust collecting chamber 112. The pre-filter also includes an air inlet component 2 and an air outlet component 3, the air inlet component 2 is arranged on the air inlet side of the shell 11 and is sealed to the shell 11, and the air outlet component 3 is arranged on the air outlet side of the shell 11 and is sealed to the shell 11.

[0045] When in use, air enters the cyclone tube 12 of the cyclone filter component 1 from the air inlet component 2, and rotates under the guidance of the cyclone blades 121, so that the solid particles contained in the air flow are thrown off the tube wall of the cyclone tube 12 under the action of centrifugal force, and then fly out from the ash discharge port 122 and fall into the dust collecting chamber 112. The dust is discharged to the outside through the ash discharge port 122 at the bottom of the dust collecting chamber 112, and the clean air is discharged to the outside through the air outlet pipe 31 of the air outlet component 3.

[0046] Further, refer to Figure 6 As shown, in step S2, the three-dimensional fluid domain model of the swirl tube 12 is divided into a first non-impeller tube segment 123, an impeller tube segment 124 and a second non-impeller tube segment 125 according to the structure of the swirl tube 12, and the first non-impeller tube segment 123, the impeller tube segment 124 and the second non-impeller tube segment 125 are respectively divided into finite element meshes, wherein the swirl blade 121 is located in the impeller tube segment 124. The finite element mesh is divided according to the characteristics of the fluid domain of the swirl tube 12, and different mesh types and mesh parameters can be used in different areas to make the simulation solution more accurate. Specifically, the first non-impeller tube segment 123, the impeller tube segment 124 and the second non-impeller tube segment 125 are divided in sequence from the direction of the air inlet component 2 to the air outlet component 3. In this embodiment, because the fluid domain motion law of the impeller tube segment 124 is complex, the mesh of the impeller tube segment 124 can be encrypted.

[0047] Further, in step S2, the non-swirl blade wall of the impeller pipe section 124, the wall of the first non-impeller pipe section 123 and the wall of the second non-impeller pipe section 125 are divided into boundary layer grids. In this embodiment, since the main collision area of ​​the particles is the wall of the swirl blade 121, the method of not setting the boundary layer grid on the wall of the swirl blade 121 is used to eliminate the error caused by the distortion of the solid particles hitting the wall of the swirl blade 121 driven by the flow field, thereby ensuring the flow resistance accuracy and improving the accuracy of the simulation calculation results of the coarse filtration efficiency. In addition, the boundary layer is a thin flow layer in which the viscous force close to the surface of the object in the high Reynolds number flow cannot be ignored, also known as the flow boundary layer, the boundary layer, the flow medium close to the boundary layer has a flow velocity close to zero, and the flow medium outside the boundary layer can basically be regarded as non-viscous, which is the mainstream area. In this way, there is bound to 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 boundary layer grids on the non-swirling blade wall of the impeller segment 124, the wall of the first non-impeller segment 123, and the wall of the second non-impeller segment 125 can further improve the accuracy of the simulation calculation results of the coarse filtration efficiency.

[0048] Further, in step S2, the number of layers of the boundary layer grid is 2 to 5. Optionally, the number of layers of the boundary layer grid can be, but is not limited to, 2, 3, 4 or 5.

[0049] Furthermore, in step S2, the gradient of the boundary layer grid is 1.2-1.5, which can make the simulation calculation result of the coarse filtration efficiency more accurate. Optionally, the gradient of the boundary layer grid can be but not limited to 1.2, 1.3, 1.4 or 1.5.

[0050] Furthermore, between step S2 and step S3, the following steps are also included: setting the wall normal compensation coefficient and the wall tangent compensation coefficient for the first non-impeller pipe segment 123, the impeller pipe segment 124, and the second non-impeller pipe segment 125. In the process of finite element meshing of the three-dimensional fluid domain model, when the particles pass through the position where the structure of the three-dimensional fluid domain model is greatly different, 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 first non-impeller pipe segment 123, the impeller pipe segment 124, and the second non-impeller pipe segment 125 as compensation, the accuracy of the simulation calculation results of the coarse filtration efficiency can be improved.

[0051] Exemplarily, the wall tangential compensation coefficients of the first non-impeller pipe section 123 and the second non-impeller pipe section 125 are both 0.8-0.89, and the wall normal compensation coefficients of the first non-impeller pipe section 123 and the second non-impeller pipe section 125 are both 0.6-0.69. Furthermore, the wall tangential compensation coefficient of the impeller pipe section 124 is 0.3-0.4; the wall normal compensation coefficient of the impeller pipe section 124 is 0.4-0.5, which further improves the accuracy of the simulation calculation results of the coarse filtration efficiency.

[0052] Specifically, the simulation method of the coarse filtration efficiency of the coarse filter cyclone tube 12 can be completed by STAR CCM+ simulation software, or by other simulation software, which will not be described in detail here. This simulation technology (optimization modeling) greatly improves the simulation accuracy. After a large number of simulation experiments, the error is within ±5% based on the experimental data.

[0053] 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 statistical method for simulating the filtration efficiency of a pre-filter, characterized in that: The steps include: S1. constructing a three-dimensional fluid domain model of the cyclone filter component (1) according to the mechanism parameters of the cyclone filter component (1) of the pre-filter; S2, performing finite element mesh division on the cyclone filter component (1), wherein the wall surface of the cyclone blade (121) in the cyclone filter component (1) is not set with a boundary layer mesh; S3, taking the entire wall surface of the dust-existing area in the cyclone filter component (1) as a simulation solution calculation area.

2. The pre-filter filtration efficiency simulation statistical method according to claim 1, characterized in that: The cyclone filter component (1) comprises: A housing (11) having an installation chamber (111) and a dust collecting chamber (112) which are communicated with each other, wherein the dust collecting chamber (112) has a dust exhaust port (1121); A plurality of swirl tubes (12) are arranged in the installation chamber (111), the swirl blades (121) are arranged in the swirl tubes (12), and a dust discharge port (122) is arranged on one side of the swirl tubes (12) close to the dust collecting chamber (112).

3. The pre-filter filtration efficiency simulation statistical method according to claim 2, characterized in that: The prefilter also includes: An air inlet component (2), the air inlet component (2) being arranged on the air inlet side of the housing (11) and being sealedly connected to the housing (11); An air outlet component (3), wherein the air outlet component (3) is arranged on the air outlet side of the shell (11) and is sealedly connected to the shell (11).

4. The pre-filter filtration efficiency simulation statistical method according to claim 2, characterized in that: In step S2, the three-dimensional fluid domain model of the swirl tube (12) is divided into a first non-impeller tube segment (123), an impeller tube segment (124) and a second non-impeller tube segment (125) according to the structure of the swirl tube (12), and finite element mesh division is performed on the first non-impeller tube segment (123), the impeller tube segment (124) and the second non-impeller tube segment (125), respectively, wherein the swirl blade (121) is located in the impeller tube segment (124).

5. The pre-filter filtration efficiency simulation statistical method according to claim 4, characterized in that: In step S2, boundary layer grids are divided for the non-swirl blade wall surface of the impeller pipe segment (124), the wall surface of the first non-impeller pipe segment (123), and the wall surface of the second non-impeller pipe segment (125).

6. The pre-filter filtration efficiency simulation statistical method according to claim 5, characterized in that: In step S2, the number of layers of the boundary layer grid is 2-5.

7. The pre-filter filtration efficiency simulation statistical method according to claim 4, characterized in that: In step S2, the gradient rate of the boundary layer grid is 1.2-1.

5.

8. The pre-filter filtration efficiency simulation statistical method according to claim 4, characterized in that: The method further includes the following steps between step S2 and step S3: setting a wall normal compensation coefficient and a wall tangential compensation coefficient for the first non-impeller pipe section (123), the impeller pipe section (124) and the second non-impeller pipe section (125).

9. The pre-filter filtration efficiency simulation statistical method according to claim 8, characterized in that: The wall tangential compensation coefficients of the first non-impeller pipe section (123) and the second non-impeller pipe section (125) are both 0.8-0.89, and the wall normal compensation coefficients of the first non-impeller pipe section (123) and the second non-impeller pipe section (125) are both 0.6-0.

69.

10. The pre-filter filtration efficiency simulation statistical method according to claim 8, characterized in that: The tangential compensation coefficient of the wall surface of the impeller pipe section (124) is 0.3-0.4; and the normal compensation coefficient of the wall surface of the impeller pipe section (124) is 0.4-0.5.

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