Shaft hole leakage simulation modeling method

Abstract

The invention provides a simulation modeling method for leakage at a shaft hole. The simulation modeling method comprises the following steps: introducing four mechanical translation interfaces in a Modelica system simulation platform in a visual operation mode; introducing default variables of four mechanical translation interfaces to package a base class model; modifying a default variable of a mechanical translation interface in the base class model by using the declaration variable as an intermediate variable so as to calculate a gap length Lp; and defining a hydraulic port of the sealing pipeline forming the shaft hole, constructing a leakage model at the shaft hole leakage position according to the equation set, and performing simulation modeling on leakage occurring at the shaft hole based on the leakage model. According to the invention, accurate calculation of the mass flow of the liquid at the shaft hole leakage position is realized, so that the technical problem that the mass flow of the leaked liquid cannot be accurately calculated based on a basic library in a simulation platform of a Modelica system in the prior art is solved.

Description

Technical Field

[0001] The invention relates to the technical field of computer simulation, and in particular to a simulation modeling method for leakage at an axial hole. Background Art

[0002] Modelica is a high-level declarative language used to describe the mathematical properties of things. It is often used in the field of engineering and can easily describe the working characteristics of different types of engineering components (such as springs, resistors, clutches, etc.). In addition, these components can be easily combined into subsystems, systems, and even architectural models. In the parts of the hydraulic / pneumatic system involving shaft-hole matching, if there is no rubber seal at the shaft-hole matching, the leakage of hydraulic oil cannot be ignored. When the hydraulic library is built based on the Modelica system-level simulation platform in the prior art to build a hydraulic system model, the hydraulic system does not have relevant components to calculate the leakage of hydraulic oil. Therefore, if you want to implement similar shaft hole leakage simulation calculations, you need to use the Modelica language to customize the leakage unit to simulate and calculate the leakage amount of the fluid (for example, hydraulic oil, air, etc.).

[0003] After searching, it was found that the Chinese invention patent with the announcement number CN105067271B disclosed a simulation modeling method of the engine cooling system based on the Modelica language. However, the prior art still cannot realize the interface parameters of the shape of the shaft hole structure (for example, radial clearance, shaft hole matching length) to define leakage, so it is impossible to accurately simulate the possible leakage at the shaft hole matching and the influence of the possible leakage at the shaft hole matching on the entire hydraulic / pneumatic.

[0004] In view of this, it is necessary to improve the existing simulation modeling method for shaft hole leakage in order to solve the above problems. Summary of the invention

[0005] The purpose of the present invention is to disclose a simulation modeling method for leakage at an axial hole, so as to solve the problem in the prior art that a Modelica system-level simulation platform can effectively and accurately evaluate the leakage that may occur at the axial hole, thereby accurately evaluating and simulating the potential impact of the leakage that may occur at the axial hole on the entire system, improving the reliability of the calculation results of the leakage at the axial hole, and improving the simplicity of modeling based on the Modelica system-level simulation platform.

[0006] To achieve the above object, the present invention provides a method for simulating and modeling leakage at a shaft hole, comprising:

[0007] Use visual operation to reference four mechanical translation interfaces in the Modelica system simulation platform;

[0008] Reference the default variables of the four mechanical translation interfaces to encapsulate the base class model;

[0009] Modify the default variables of the mechanical translation interface in the base class model using the declared variables as intermediate variables to calculate the gap length Lp;

[0010] Define a hydraulic port of a sealing pipeline forming an axial hole, so as to construct a leakage model of the axial hole leakage according to the following set of equations, and simulate and model the leakage occurring at the axial hole based on the leakage model;

[0011]

[0012] Parameter ρ is the fluid density, parameter r is the diameter of the gap size, parameter Lp is the gap length, μ is the dynamic viscosity of the fluid, parameter c is the gap amount in the diameter direction, parameter e is the eccentricity, parameter abs(dp) is the absolute value of the pressure drop caused by the fluid leakage at the shaft hole at the hydraulic port with the gap length Lp, and parameter C dmax is the flow coefficient and is a constant.

[0013] As a further improvement of the present invention, the visualization operation method is specifically: four mechanical translation interfaces are referenced in a drag-and-drop manner in a graphical user interface formed by a Modelica system simulation platform; the mechanical translation interfaces include: flange_a, flange_b, support_a and support_b.

[0014] As a further improvement of the present invention, the base class model is a Basic base class model, and the axial hole leakage simulation modeling method further includes: inheriting four mechanical translation interfaces from the Basic base class model.

[0015] As a further improvement of the present invention, it also includes: forming corresponding displacement variables for the mechanical translation interface based on the displacement, using declared variables as intermediate variables to combine with flange_a, flange_b, support_a and support_b to form displacement variables respectively; the displacement variables include: flange_a.s, flange_b.s, support_a.s and support_b.s.

[0016] As a further improvement of the present invention, it also includes: forming corresponding external force variables for the mechanical translation interface based on the external force f, and the external force variables include: flange_a.f, flange_b.f, support_a.f and support_b.f.

[0017] As a further improvement of the present invention, the external force f is the sum of the forces generated by the fluid on the mechanical translation interface flange_a, the mechanical translation interface flange_b, the mechanical translation interface support_a and the mechanical translation interface support_b along the direction of the sealed pipeline.

[0018] As a further improvement of the present invention, the hydraulic port includes: a hydraulic inlet port_a through which fluid flows into the sealed pipeline and a hydraulic outlet port_b through which fluid flows out of the sealed pipeline.

[0019] As a further improvement of the present invention, it also includes: introducing a transition length L_trans into the leakage model to use the transition length L_trans as a declared variable.

[0020] As a further improvement of the present invention, the present invention further includes: comparing the gap length Lp with the transition length L_trans;

[0021] If the gap length Lp is less than the transition length L_trans, the fluid mass flow m_flow is calculated based on the right-hand formula of the leakage model;

[0022] If the gap length Lp≥transition length L_trans, the fluid mass flow rate m_flow is calculated based on the left-hand formula of the leakage model.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The present invention refers to the mechanical translation interface in the basic mechanical library provided in the Modelica system simulation platform, establishes a base class model based on the mechanical translation interface, uses the equation of shaft hole leakage in the hydraulic interface, and finally realizes the accurate calculation of the liquid mass flow m_flow at the shaft hole leakage, thereby solving the technical problem that the basic library provided in the Modelica system simulation platform in the prior art cannot accurately calculate the leaked liquid mass flow. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is the geometric model of the closed pipeline in the hydraulic system;

[0026] Figure 2 A schematic diagram of referencing four translational mechanical interfaces in the Modelica system simulation platform based on a drag-and-drop modeling method in the visual interface of the Modelica system simulation platform;

[0027] Figure 3 The schematic diagram of the default variables for the mechanical translation interface and the definition of the Basic base class model;

[0028] Figure 4In order to form corresponding displacement variables for the mechanical translation interfaces based on the displacement, the declared variables are used as intermediate variables to be combined with the four mechanical translation interfaces of flange_a, flange_b, support_a and support_b to form schematic diagrams of the displacement variables respectively;

[0029] Figure 5 A schematic diagram of the mathematical model corresponding to the equation group for calculating the change of the shaft-hole matching length Lp;

[0030] Figure 6 Schematic diagram of the leakage model. DETAILED DESCRIPTION

[0031] The present invention is described in detail below in conjunction with the various embodiments shown in the accompanying drawings, but it should be noted that these embodiments are not limitations of the present invention, and any equivalent transformations or substitutions in functions, methods, or structures made by ordinary technicians in the field based on these embodiments are all within the scope of protection of the present invention.

[0032] Ginseng Figures 1 to 6 A specific implementation of a method for simulating and modeling leakage at a shaft hole of the present invention (hereinafter referred to as "the method") is shown. The method disclosed in this embodiment is intended to simulate and model the leakage that may occur at the shaft hole matching position of a completely sealed closed pipeline (for example, a hydraulic pipeline of a hydraulic system or an engine system of an internal combustion engine) to evaluate the liquid mass flow loss caused by leakage at the shaft hole matching position and the pressure loss at both ends of the closed pipeline.

[0033] Ginseng Figure 1 As shown in the figure, in a completely sealed closed pipeline, under the action of the pressure difference Δp upstream of the closed pipeline, the volume flow rate Q in the closed pipeline can be determined because the flow resistance in the closed pipeline is also determined. However, in some special closed pipelines, there is a clearance fit between the shaft hole, such as the fit clearance between the piston and the cylinder. The aforementioned fit clearance reference Figure 1 As shown. Due to the existence of the matching clearance, the closed pipeline cannot be completely sealed. Therefore, compared with the completely sealed closed pipeline, the volume flow Q is lost. Therefore, due to the reasons such as the shaft hole clearance, a small amount of fluid flowing or temporarily stored in the cavity of the hydraulic component and system will cross the cavity boundary and flow out from the high-pressure side to the low-pressure side, which is defined as leakage.

[0034] The embodiment discloses a method for simulating and modeling leakage at a shaft hole to Figure 1The sealing pipeline shown in the figure is simulated and modeled when leakage occurs at the shaft hole, so as to accurately evaluate the adverse effects of the fluid (e.g., hydraulic oil or gas) objectively existing at the shaft hole on the entire hydraulic system or pneumatic system due to leakage. The method disclosed in this embodiment, by referencing the mechanical translation interface (i.e., basic library) in the basic mechanical library of the Modelica language, establishes a Basic base class model based on the mechanical translation interface, and uses the equation group of shaft hole leakage at the hydraulic port, finally realizes the detection and calculation of shaft hole leakage (i.e., the fluid mass flow m_flow corresponding to the leakage at the shaft hole), and solves the technical problem in the prior art that the basic library in the Modelica system simulation platform based on the Modelica language cannot accurately calculate the leaked fluid mass flow m_flow.

[0035] A method for simulating and modeling leakage at an axial hole disclosed in this embodiment includes the following steps.

[0036] Four mechanical translation interfaces are referenced in the Modelica system simulation platform in a visual operation mode. The so-called visual operation mode is specifically: four mechanical translation interfaces are referenced in a drag-and-drop manner in the graphical user interface 100 formed by the Modelica system simulation platform. The mechanical translation interfaces introduced in this embodiment include: flange_a, flange_b, support_a and support_b. Specifically, Modelica interfaces, such as mechanical translation interfaces, rotation interfaces, hydraulic ports and other components are all ready-made, but can only realize the most basic functions, so the user only needs to manually drag them directly into the base class model. The default variables of the four mechanical translation interfaces are referenced to encapsulate the base class model. The base class model is the Basic base class model. The simulation modeling method for leakage at the shaft hole also includes: the Basic base class model inherits the four mechanical translation interfaces, and specifically inherits the four mechanical translation interfaces of flange_a, flange_b, support_a and support_b at the same time.

[0037] There are many basic elements in Modelica, and the basic elements are defined by the language types contained in Modelica. There are many language types that form basic elements, for example, base class model: Basic model; model: model; class: class, etc., and can be formed based on base class model, model or class, etc. to define different non-basic elements. At the same time, in order to improve the readability of the computer code formed by the Modelica language, before calculating variables such as leakage and pressure drop caused by shaft hole parameters, it is necessary to put the mechanical translation interface, intermediate variables, etc. into a base class model (that is, the Basic base class model below). The model in this embodiment refers to the Basic model type. The computer programming method starts with Basic model and ends with End Basic. When the formal calculation begins in the later stage, the four mechanical translation interfaces mentioned above can be directly inherited in the Modelica system simulation platform to reference the specific parameters. Figure 2 shown.

[0038] Use declared variables as intermediate variables to modify the default variables of the mechanical translation interface in the base class model to calculate the gap length Lp. The corresponding displacement variables are formed for the mechanical translation interface based on the displacement, and the declared variables are used as intermediate variables to combine with flange_a, flange_b, support_a and support_b to form displacement variables respectively. Specifically, the displacement variables include: flange_a.s, flange_b.s, support_a.s and support_b.s, and all are vectors. In this embodiment, the simulation modeling method for leakage at the shaft hole also includes: forming corresponding external force variables for the mechanical translation interface based on the external force f, and the external force variables include: flange_a.f, flange_b.f, support_a.f and support_b.f. The external force f is the sum of the vectors of the forces formed by the mechanical translation interface flange_a, the mechanical translation interface flange_b, the mechanical translation interface support_a and the mechanical translation interface support_b along the direction of the sealed pipeline.

[0039] like Figure 2 As shown in the figure, drag-and-drop modeling is used in the Modelica system simulation platform, and specifically in Figure 2 The visualization interface 100 of the Modelica system simulation platform shown in the figure references four mechanical translation interfaces (flange / support): flange_a, flange_b, support_a and support_b. Figure 3As shown. In Modelica, there is a default relationship that the flow variables at the same point are 0 and the potential variables are the same. Therefore, by defining parameters, defining variables (i.e., flange_a, flange_b, support_a, and support_b), and defining equations, we can get Figure 2 The flow variables and potential variables of the four mechanical translation interfaces in the example above produce corresponding results, such as Figure 3 The default variables corresponding to the four mechanical translation interfaces in Modelica are shown in Figure 2.

[0040] based on Figure 3 , directly reference the default variables corresponding to the four mechanical translation interfaces, and define them uniformly as a Basic base class model. The Basic base class model in this embodiment is used to convert the displacements between the four mechanical translation interfaces (i.e., flange_a, flange_b, support_a, support_b) (for example, Figure 3 flange_a.s in , etc.) and forces (e.g. Figure 4 flange_a.f, flange_b.f, etc.) in the equation, and define a new variable f. Figure 4 As shown. The above four mechanical translation interfaces are all interfaces, and flange_a.s, flange_b.s, support_a.s, and support_b.s involved in the following are all variables. The variable f here is an external force, which is different from the force of the interface itself such as flange_a.f. The variable f will form an equation with a flow variable of 0 with the force of the interface such as flange_a.f and flange_b.f. The vector s_rel_a and the vector s_rel_ab are used for subsequent calculations, such as Figure 4 . Figure 4 In the example, s_rel_a is the position of the variable flange_a.s, the default variable of flange_a itself, relative to the vector support_a.s. flange_a.s-support_a.s=s_rel_a.

[0041] A hydraulic port of a sealing pipeline forming the shaft hole is defined to construct a leakage model of the shaft hole leakage according to the following set of equations (hereinafter referred to as "equation set (1)"), and a simulation model of the leakage occurring at the shaft hole is performed based on the leakage model;

[0042]

[0043] The meanings of the parameters in equation group (1) are as follows: parameter ρ is the fluid density, parameter r is the diameter of the gap size, parameter Lp is the gap length, μ is the dynamic viscosity of the fluid, parameter c is the gap amount in the diameter direction, parameter e is the eccentricity, parameter abs(dp) is the absolute value of the pressure drop caused by the fluid leakage at the shaft hole of the gap length Lp at the hydraulic port, and parameter C dmax is the flow coefficient and is a constant. The hydraulic port includes: a hydraulic inlet port_a through which the fluid flows into the sealed pipeline and a hydraulic outlet port_b through which the fluid flows out of the sealed pipeline.

[0044] The main code of the Basic base class model is shown in the following equation group (2). The Basic base class model in equation group (2) defines an additional switch variable. The switch variable, as a declared variable, can be used as an intermediate variable in this embodiment, and is specifically as follows: in the fixed area of ​​the Modelica language, enter protected, start a new line, enter the Boolean type, and name it switch to complete the definition of this switch. Use this additional switch variable as an intermediate variable to define the subtraction of the two vector variables flange_a.s and flange_b.s, that is, the direction represented by the vector s_rel_ab. Due to the relative position of the shaft hole, the gap length Lp formed in the sealed pipeline may change. Finally, the equation group for calculating the change in the shaft hole matching length based on the Modelica computer code is shown in the following equation group (2).

[0045]

[0046] The simulation modeling method for leakage at the shaft hole disclosed in this embodiment further includes: introducing a transition length L_trans into the leakage model (i.e., the aforementioned equation group (1)) to use the transition length L_trans as a declared variable. The method further includes: comparing the gap length Lp with the transition length L_trans; if the gap length Lp is less than the transition length L_trans, calculating the fluid mass flow m_flow based on the right-hand formula of the leakage model (i.e., see the following formula (2)).

[0047]

[0048] If the gap length Lp≥transition length L_trans, the fluid mass flow rate m_flow is calculated based on the left-hand side formula of the aforementioned leakage model (ie, see the following formula (3)).

[0049]

[0050] The parameters contained in the above formula (2) and formula (3) have the same meaning as the parameters contained in the above equation group (1).

[0051] Figure 4 s_rel_ab, which is the change in the shaft-hole length when calculating leakage (i.e., Figure 5 The gap length Lp in the formula in Basic is Lp). On the basis of Basic citing the Basic base class model, two additional hydraulic ports (i.e., hydraulic port port_a and hydraulic port port_b) are defined. After the shaft hole is subjected to force or displacement, the shaft hole gap changes and different leakage amounts are generated. The aforementioned features (i.e., Basic base class model, hydraulic ports, etc.) are coupled together, and the calculation of the variables between mechanics and hydraulics is realized by defining a set of equations in Modelica, and finally a Leakage model (i.e., leakage model) is formed. The specific parameters are Figure 6 As shown. The specific computer code of the equation group (1) in Modelica is shown in the following code (1) and code (2). The equation group (1) for calculating leakage and characterizing the leakage model is shown above. The calculation formula on the left side of the equation group (1) (i.e., formula (3)) is the calculation formula for calculating the fluid mass flow m_flow of the leakage, and the calculation formula on the right side of the equation group (1) (i.e., formula (2)) is the calculation formula for the liquid volume flow Q considering the intercepting hole.

[0052] The left side of equation group (1) is the calculation formula for calculating the leakage fluid mass flow m_flow, and the right side of equation group (1) is the calculation formula for the fluid mass flow of the gap hole. The leakage caused by the shaft hole fit is related to the gap length Lp. Figure 6 The variables related to the key mechanical translation interface have been explained before and will not be repeated here. The specific parameters / variables are explained as follows: The parameters on the left side of the equation group (1) include: the density ρ of the hydraulic oil, the gap size (diameter r) is a known input quantity, the dynamic viscosity μ is a known input quantity, the gap length Lp is a quantity to be determined, the gap amount c in the diameter direction is a known input quantity, the eccentricity e is a known input quantity and the pressure drop abs (dp) is a known input quantity or a quantity transmitted from other component related interfaces (the equation referred to by code (2) refers to the difference between the hydraulic port port_a.p and the hydraulic port port_b.p, that is, dp), C dmax is the flow coefficient, which is a constant, equivalent to the Modelica code,

[0053] Parameter C in code (1) and code (2) dmaxis a constant. Under normal circumstances, by substituting this gap length Lp into the calculation formula on the right side of the equation group (1), the fluid mass flow rate m_flow of the gap hole can be calculated. The gap length Lp in the calculation formula on the right side of the equation group (1) is in the denominator position of the equation group. Obviously, when the gap length Lp approaches 0, it means that the gap length Lp is very small, and the fluid mass flow rate m_flow calculated in the calculation formula on the right side of the equation group (1) will be distorted. At this time, since the left side of the equation group (1) is the calculation formula for the fluid mass flow rate m_flow of the throttling hole, it has nothing to do with the gap length Lp. Therefore, in the parameter C dmax When the parameters ρ, r, c, and abs(dp) are all known, the fluid mass flow rate m_flow of the throttle hole can be calculated. If the calculation result of the fluid mass flow rate m_flow of the throttle hole (i.e., the calculation formula on the left side of the equation group (1)) is used to forcibly assign the fluid mass flow rate m_flow of the right gap hole. In other words, the fluid mass flow rate m_flow of the right gap hole is forced to be equal to the fluid mass flow rate m_flow of the throttle hole. At this time, the critical Lp can be easily obtained and defined as the transition length L_trans.

[0054] Another original technical idea of ​​the method disclosed in this embodiment is to introduce the transition length L_trans into the leakage model, so as to use the transition length L_trans as a declared variable. Based on the equation group of the mechanical translation interface and the throttle hole mass flow m_flow, and introducing the transition length L_trans as a declared variable, the transition length L_trans is used to limit the gap length Lp to a minimum value or a smaller value, thereby preventing the gap length Lp from being too small, which causes an error in the calculation of the fluid mass flow m_flow due to the shaft hole leakage. After obtaining the transition length L_trans, there are two calculation methods to determine the fluid mass flow m_flow.

[0055] The first calculation method: If only the calculation formula on the right side of the equation group (1) is used to calculate the fluid mass flow rate m_flow of the gap hole, when the gap length Lp is long enough (for example, much larger than the gap c in the diameter direction), the calculated value s_rel_ab in the previous mechanical translation interface is used to represent the gap length Lp; if the gap length Lp is very small (for example, close to 0), the transition length L_trans is directly assigned to the gap length Lp.

[0056] The second calculation method: When the gap length Lp ≥ transition length L_trans, the gap calculation formula on the right side of the equation group (1) is used to calculate the fluid mass flow m_flow of the gap hole. When the gap length Lp < transition length L_trans, the calculation formula on the left side of the equation group (1) is used to calculate the fluid mass flow m_flow of the gap hole. In this way, it can be ensured that when the gap length Lp tends to 0, the fluid mass flow m_flow of the gap hole can also be output. Therefore, the calculation of the critical value of the gap length Lp (i.e., the transition length L_trans) is crucial.

[0057] The computer program code written based on Modelica code in equation group (1) (hereinafter referred to as "code (1)") is as follows:

[0058]

[0059] Finally, when Modelica calculates the fluid leakage at the axial hole of the sealed pipeline, combined with other main defined parameters and variables, the computer program code of the Modelica equation group (hereinafter referred to as "Code (2)") is as follows:

[0060]

[0061] The relevant parameters and variables of the Modelica code equations are explained below. dmax : Flow coefficient; when calculating leakage, Figure 1 In the geometric model of the closed pipeline in the hydraulic system shown, the diameter of the hole is r; the clearance in the diameter direction of the shaft hole is c; the eccentricity of the shaft hole is e; the clearance length is Lp; Figure 1 The pressure of the hydraulic port on the left side of the middle seal line is p_a, Figure 1 The pressure of the hydraulic port on the right side of the sealed pipeline is p_b. The value of the fluid mass flow m_flow in code (1) is related to the transition length L_trans. Sealed pipeline and closed pipeline have the same technical meaning.

[0062] Through the steps of defining mechanical translation interface, establishing base class model, referencing base class model, defining hydraulic port, defining related variables, etc. in Modelica, the calculation of complex problems can be realized step by step through the equations between interfaces and variables. Therefore, one of the notable features of Modelica language is the definition of flow variables and potential variables between interfaces, and specifically: the potential variables at the connection are equal and the sum of the flow variables at the connection is 0. Therefore, the four mechanical translation interfaces defined in the present invention, such as flange_a, support_a, flange_b, support_b, and hydraulic ports (i.e., port_a, port_b) will also have this relationship (i.e., the potential variables at the connection are equal and the sum of the flow variables at the connection is 0). The equation port_a.m_flow+port_b.m_flow=0 in code (2) is the application of flow variable 0.

[0063] This method is based on the mathematical model description of the shaft hole leakage, uses the Modelica system simulation platform and establishes the equation group based on the Modelica language, uses the characteristics of the flow variables and potential variables of Modelica, and based on the influence of the transition length L_trans on the leaking fluid mass flow, etc., finally uses the Modelica language to calculate the leaking fluid mass flow m_flow, the pressure drop dp at both ends of the sealed pipeline and other variables to build a leakage model. Through the shaft hole leakage simulation modeling method disclosed by the present invention, the leakage can be defined according to the shaft hole related size parameters (for example, the density (ρ) of the pressure oil, the gap size (diameter r) is a known input, and the dynamic viscosity (μ)), and creatively takes into account the fluid mass flow of the leakage element under the critical length L_trans of the shaft hole, thereby improving the reliability of the calculation results of the fluid leakage at the shaft hole, and at the same time, it can also calculate the pressure loss on both sides of the leakage element; finally, the four mechanical translation interfaces and two hydraulic ports (i.e., port_a, port_b) of the leakage element can couple the leakage element with other elements in the hydraulic / pneumatic system for calculation, and finally realize the evaluation of the impact on the entire hydraulic / pneumatic system.

[0064] The method disclosed in this embodiment realizes the accurate calculation of the liquid mass flow m_flow at the shaft hole leakage, thereby solving the technical problem that the basic library provided in the Modelica system simulation platform in the prior art cannot accurately calculate the leaking liquid mass flow.

[0065] The series of detailed descriptions listed above are only specific descriptions of feasible implementation methods of the present invention. They are not intended to limit the scope of protection of the present invention. Any equivalent implementation methods or changes that do not deviate from the technical spirit of the present invention should be included in the scope of protection of the present invention.

[0066] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0067] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A simulation modeling method for leakage at an axial hole, characterized in that: include: Use visual operation to reference four mechanical translation interfaces in the Modelica system simulation platform; Reference the default variables of the four mechanical translation interfaces to encapsulate the base class model; Modify the default variables of the mechanical translation interface in the base class model using the declared variables as intermediate variables to calculate the gap length Lp; Define a hydraulic port of a sealing pipeline forming an axial hole, so as to construct a leakage model of the axial hole leakage according to the following set of equations, and simulate and model the leakage occurring at the axial hole based on the leakage model; Parameter ρ is the fluid density, parameter r is the diameter of the gap size, parameter Lp is the gap length, μ is the dynamic viscosity of the fluid, parameter c is the gap amount in the diameter direction, parameter e is the eccentricity, parameter abs(dp) is the absolute value of the pressure drop caused by the fluid leakage at the shaft hole at the hydraulic port with the gap length Lp, and parameter C dmax is the flow coefficient and is a constant.

2. The method for simulating and modeling leakage at an axial hole according to claim 1, characterized in that: The visualization operation method is specifically: referencing four mechanical translation interfaces in a drag-and-drop manner in a graphical user interface formed by a Modelica system simulation platform; The mechanical translation interface includes: flange_a, flange_b, support_a and support_b.

3. The method for simulating and modeling leakage at an axial hole according to claim 2, characterized in that: The base class model is a Basic base class model, and the axial hole leakage simulation modeling method further includes: inheriting four mechanical translation interfaces from the Basic base class model.

4. The method for simulating and modeling leakage at an axial hole according to claim 3, characterized in that: Also includes: The mechanical translation interface forms corresponding displacement variables based on the displacement, and uses the declared variables as intermediate variables to combine with flange_a, flange_b, support_a and support_b to form displacement variables respectively; the displacement variables include: flange_a.s, flange_b.s, support_a.s and support_b.s.

5. The method for simulating and modeling leakage at an axial hole according to claim 3, characterized in that: Also includes: Corresponding external force variables are respectively formed for the mechanical translation interface based on the external force f, and the external force variables include: flange_a.f, flange_b.f, support_a.f and support_b.f.

6. The method for simulating and modeling leakage at an axial hole according to claim 5, characterized in that: The external force f is the sum of the forces generated by the fluid on the mechanical translation interface flange_a, the mechanical translation interface flange_b, the mechanical translation interface support_a and the mechanical translation interface support_b along the direction of the sealed pipeline.

7. The method for simulating and modeling leakage at an axial hole according to claim 1, characterized in that: The hydraulic port includes: a hydraulic inlet port_a through which fluid flows into the sealed pipeline and a hydraulic outlet port_b through which fluid flows out of the sealed pipeline.

8. The method for simulating and modeling leakage at an axial hole according to claim 1, characterized in that: Also includes: A transition length L_trans is introduced into the leakage model so as to take the transition length L_trans as a declared variable.

9. The method for simulating and modeling leakage at an axial hole according to claim 8, characterized in that: Also includes: Compare the gap length Lp with the transition length L_trans; If the gap length Lp is less than the transition length L_trans, the fluid mass flow m_flow is calculated based on the right-hand formula of the leakage model; If the gap length Lp≥transition length L_trans, the fluid mass flow rate m_flow is calculated based on the left-hand formula of the leakage model.

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