Method for predicting sealing performance of contact type end face of engine driven pressure groove structure

Abstract

The invention belongs to the field of aero-engine design, and particularly relates to an engine driving pressure groove structure contact type end face sealing performance prediction method which comprises the steps that the actually-measured rotor temperature or leakage amount is obtained, and the air film force of contact type end face sealing is inversely calculated according to a dynamic pressure groove structure; then, equivalent gas film / liquid film thickness is determined according to the dynamic pressure groove structure, and the structure opening force is calculated; the contact state and the contact load are evaluated according to the opening force and the aerodynamic force of the dynamic pressure groove structure and the closing force determined by the spring force, whether the sealing face is opened or not is judged, and if the sealing face is closed, sealing performance detection is conducted; according to the contact state and the contact load, the leakage characteristic and the friction characteristic of the end face seal are calculated and predicted; by solving the problem of'zero film thickness' prediction of contact type sealing, accurate prediction and design optimization of the sealing performance of the end face of the driving pressure groove structure are realized, and the reliability, the service life and the engineering applicability of a sealing system are remarkably improved.

Description

Technical Field

[0001] This application belongs to the field of aero-engine design, and specifically relates to a method for predicting the sealing performance of the contact end face of an engine-driven pressure groove structure. Background Technology

[0002] To address the issues of high wear rate and short lifespan of contact-type end face seals in aero engines, a dynamic pressure groove structure has been designed on the dynamic ring of the end face seal to reduce the contact load. The feasibility of this technology has been confirmed through experiments, but there is currently no method for predicting the performance of contact-type end face seals with dynamic pressure groove structures.

[0003] Existing non-contact end-face sealing performance prediction methods calculate the gas / liquid film thickness based on the balance between closing and opening forces, and determine the sealing leakage characteristics based on the calculated thickness.

[0004] For the end face seal of the contact-type dynamic pressure groove structure, since the sealing surface is closed and the gas film / liquid film thickness is 0, the sealing leakage performance cannot be calculated using the above method.

[0005] For both contact-type end face seals and non-contact end face seals with pressure grooves, there are currently methods for predicting sealing performance. However, due to the complexity of the operating conditions of aero-engines and the need for weight reduction, it is impossible to establish a stable non-contact end face seal state. Therefore, it is necessary to adopt a contact-type end face seal structure with pressure grooves. Currently, there is no performance prediction method for this structure. Summary of the Invention

[0006] To address the aforementioned issues, this application provides a method for predicting the performance of contact-type end-face seals driven by engine-driven pressure groove structures, thereby resolving the problem in the prior art that it is difficult to predict the performance of contact-type end-face seals driven by pressure groove structures.

[0007] The technical solution of this application is: a method for predicting the sealing performance of an engine-driven pressure groove structure contact end face, including:

[0008] The sealing dynamic ring and sealing stationary ring are designed based on the input conditions, and their structures are determined.

[0009] Based on the structure of the sealing dynamic ring and the sealing static ring, the material selection of the elastic element and the design of the elastic specific pressure are carried out to obtain the elastic element and the spring force.

[0010] The material of the O-ring is determined based on the elastic element;

[0011] Based on the initial determination of the dynamic pressure groove structure design scheme according to the working conditions, the dynamic pressure groove structure design is carried out.

[0012] Obtain the actual measured rotor temperature or leakage, and back-calculate the gas film force of the contact end face seal based on the dynamic pressure groove structure; then determine the equivalent gas film / liquid film thickness based on the dynamic pressure groove structure to calculate the structural opening force.

[0013] The contact state and contact load are assessed based on the opening force, aerodynamic force, and spring force of the dynamic pressure groove structure, and it is determined whether the sealing surface is open. If the sealing surface is closed, the sealing performance is tested.

[0014] The leakage and friction characteristics of the end face seal are calculated and predicted based on the contact state and contact load.

[0015] Preferably, the specific method for calculating the gas film force of the contact-type end face seal based on the dynamic pressure groove structure is as follows:

[0016] The rotor temperature is measured using an infrared temperature sensor and a rotor heat sensor; a separate leakage cavity is established, and a flow sensor is set up to measure the leakage cavity.

[0017] Based on the rotor temperature or leakage, and combined with the Reynolds equation for multiphase flow considering the oil-gas ratio or the contact force model considering surface roughness, the gas film force of the designed contact end face seal is calculated in reverse. The theoretical formula or numerical simulation parameters are selected based on the working conditions under the test conditions, the surface roughness of the sealing surface, and the oil-gas ratio of the sealing medium. Then, the equivalent gas film / liquid film thickness is calculated through the gas film force.

[0018] Preferably, the elastic force of the elastic element is greater than the sum of the inertial force of the stationary ring and the axial frictional force of the sealing ring.

[0019] Preferably, the compression ratio of the O-ring material is controlled between 8% and 12%.

[0020] Preferably, the sealing dynamic ring and sealing stationary ring are designed, including the selection of materials for the dynamic ring and the stationary ring, the design of the gap between the stationary ring and the housing, and the design of the flatness and roughness of the sealing end face.

[0021] Preferably, the specific method for determining whether the sealing surface is open is as follows:

[0022] By using the opening force, aerodynamic force, and spring force of the dynamic pressure groove structure, the closing force of the dynamic pressure groove structure is calculated using CFO simulation. The opening force is compared with the closing force. When the opening force is greater than the closing force, it is determined that the sealing surface is open and the parameters need to be readjusted and recalculated. If the opening force is less than the closing force by a certain proportion, it means that the sealing surface is completely closed.

[0023] Preferably, the specific method for determining the equivalent gas film / liquid film thickness and calculating the structural opening force based on the dynamic pressure groove structure is as follows: obtain the initial geometric clearance of the dynamic pressure groove structure, and calculate the average film thickness h between the sealing surfaces. eq The calculation formula is:

[0024] h eq =h0+Δh thermal −δ roughness −δ liquid ;

[0025] Where h0 is the initial geometric gap, Δh thermal δ represents the change in film thickness due to expansion. roughness δ represents the reduction in film thickness caused by rough peak contact. liquid The thickness of the interstitial space occupied by the liquid phase;

[0026] The average film thickness h eq The input is placed into a multiphase flow model, and the opening force is calculated through finite element simulation.

[0027] The method for predicting the sealing performance of the contact-type end face of the engine-driven pressure groove structure in this application has the following advantages:

[0028] By solving the problem of predicting "zero film thickness" in contact seals, accurate prediction and design optimization of the sealing performance of the end face of the pressure groove structure were achieved, significantly improving the reliability, lifespan and engineering applicability of the sealing system.

[0029] By combining "actually measured rotor temperature / leakage to calculate gas film force" and "equivalent film thickness to calculate opening force", the prediction barrier in the zero film thickness scenario is broken through, and a full-process performance prediction system for driving groove contact seal is established.

[0030] The equivalent gas film / liquid film thickness is determined by theoretical / experimental methods. The opening force under the action of the dynamic pressure groove structure is calculated based on the thickness. The contact load and contact state of the sealing surface are determined based on the opening force, and then the sealing leakage characteristics and temperature rise of the contact end face seal of the driving pressure groove structure are determined. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the overall process of this application. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are only some, not all, of the embodiments of this application. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0033] The first aspect of this application provides a method for predicting the sealing performance of a contact-type end face seal of an engine-driven pressure groove structure. Addressing the problem that the gas / liquid film thickness of the contact-type dynamic pressure groove structure end face seal is zero, making it impossible to calculate the sealing leakage performance, the method determines the equivalent gas / liquid film thickness through theoretical / experimental methods, calculates the opening force under the action of the dynamic pressure groove structure based on this thickness, determines the contact load and contact state of the sealing surface based on this opening force, and thus determines the sealing leakage characteristics and temperature rise of the contact-type end face seal of the engine-driven pressure groove structure.

[0034] like Figure 1 It includes the following steps:

[0035] Step S100: Design the sealing dynamic ring and sealing stationary ring according to the input conditions, including selecting materials for the dynamic ring and stationary ring, designing the gap between the stationary ring and the housing, designing the flatness and roughness of the sealing end face, etc., and determine the structure of the sealing dynamic ring and sealing stationary ring.

[0036] Step S200: Based on the structure of the sealing dynamic ring and the sealing stationary ring, select the material of the elastic element and design the elastic specific pressure. The elastic force of the elastic element is greater than the sum of the inertial force of the stationary ring and the axial friction force of the sealing ring, so as to obtain the elastic element and the spring force.

[0037] Step S300: Determine the material of the O-ring based on the elastic element, and control the compression rate of the O-ring material to be between 8% and 12%.

[0038] Step S400: Initially determine the dynamic pressure groove structure design scheme based on the working conditions, and carry out the dynamic pressure groove structure design. The dynamic pressure groove structure types include face-shaped groove structure and spiral groove structure.

[0039] Step S500: Obtain the actual measured rotor temperature or leakage amount, and calculate the gas film force of the contact end face seal based on the dynamic pressure groove structure.

[0040] The specific method for back-calculating the film force of the contact-type end-face seal based on the dynamic pressure groove structure is as follows:

[0041] The rotor temperature is measured using an infrared temperature sensor and a rotor heat sensor; a separate leakage cavity is established, and a flow sensor is set up to measure the leakage cavity.

[0042] Based on the rotor temperature or leakage, and combined with the Reynolds equation for multiphase flow considering the oil-gas ratio or the contact force model considering surface roughness, the gas film force of the designed contact end face seal is calculated in reverse. The theoretical formula or numerical simulation parameters are selected based on the working conditions under the test conditions, the surface roughness of the sealing surface, and the oil-gas ratio of the sealing medium. Then, the equivalent gas film / liquid film thickness is calculated through the gas film force.

[0043] Step S600, then determine the equivalent gas film / liquid film thickness based on the dynamic pressure groove structure and calculate the structural opening force.

[0044] Preferably, the specific method for determining the equivalent gas film / liquid film thickness and calculating the structural opening force based on the dynamic pressure groove structure is as follows: obtain the initial geometric clearance of the dynamic pressure groove structure, and calculate the average film thickness h between the sealing surfaces. eq The calculation formula is:

[0045] h eq =h0+Δh thermal −δ roughness −δ liquid ;

[0046] Where h0 is the initial geometric gap, Δh thermal δ represents the change in film thickness due to expansion. roughness δ represents the reduction in film thickness caused by rough peak contact. liquid The thickness of the interstitial space occupied by the liquid phase;

[0047] The average film thickness h eq The input is placed into a multiphase flow model, and the opening force is calculated through finite element simulation.

[0048] In step S700, the contact state and contact load are evaluated based on the opening force, aerodynamic force, and spring force of the dynamic pressure groove structure, and it is determined whether the sealing surface is open. If the sealing surface is closed, the sealing performance is tested.

[0049] Preferably, the specific method for determining whether the sealing surface is open is as follows:

[0050] By using the opening force, aerodynamic force, and spring force of the dynamic pressure groove structure, the closing force of the dynamic pressure groove structure is calculated using CFO simulation. The opening force is compared with the closing force. When the opening force is greater than the closing force, it is determined that the sealing surface is open and the parameters need to be readjusted and recalculated. If the opening force is less than the closing force by a certain proportion, it means that the sealing surface is completely closed.

[0051] Step S800: Calculate and predict the leakage and friction characteristics of the end face seal based on the contact state and contact load. Use existing calculation methods to calculate the leakage and friction characteristics, compare them with the current standard leakage and friction characteristics, and determine whether they meet the design requirements. If yes, complete the design; otherwise, modify the parameters and recalculate.

[0052] In summary, this application has the following advantages:

[0053] By solving the problem of predicting "zero film thickness" in contact seals, accurate prediction and design optimization of the sealing performance of the end face of the pressure groove structure were achieved, significantly improving the reliability, lifespan and engineering applicability of the sealing system.

[0054] By combining "actually measured rotor temperature / leakage to calculate gas film force" and "equivalent film thickness to calculate opening force", the prediction barrier in the zero film thickness scenario is broken through, and a full-process performance prediction system for driving groove contact seal is established.

[0055] The equivalent gas film / liquid film thickness is determined by theoretical / experimental methods. The opening force under the action of the dynamic pressure groove structure is calculated based on the thickness. The contact load and contact state of the sealing surface are determined based on the opening force, and then the sealing leakage characteristics and temperature rise of the contact end face seal of the driving pressure groove structure are determined.

[0056] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for predicting the sealing performance of an engine-driven pressure groove structure contact end face, characterized in that, include: The sealing dynamic ring and sealing stationary ring are designed based on the input conditions, and their structures are determined. Based on the structure of the sealing dynamic ring and the sealing static ring, the material selection of the elastic element and the design of the elastic specific pressure are carried out to obtain the elastic element and the spring force. The material of the O-ring is determined based on the elastic element; Based on the initial determination of the dynamic pressure groove structure design scheme according to the working conditions, the dynamic pressure groove structure design is carried out. Obtain the actual measured rotor temperature or leakage, and calculate the gas film force of the contact end face seal based on the dynamic pressure groove structure. Then, the equivalent gas film / liquid film thickness is determined based on the dynamic pressure groove structure, and the structural opening force is calculated. The contact state and contact load are assessed based on the opening force, aerodynamic force, and spring force of the dynamic pressure groove structure, and it is determined whether the sealing surface is open. If the sealing surface is closed, the sealing performance is tested. The leakage and friction characteristics of the end face seal are calculated and predicted based on the contact state and contact load.

2. The method for predicting the sealing performance of the contact-type end face of the engine-driven pressure groove structure as described in claim 1, characterized in that, The specific method for back-calculating the film force of the contact-type end-face seal based on the dynamic pressure groove structure is as follows: The rotor temperature is measured using an infrared temperature sensor and a rotor heat sensor; a separate leakage cavity is established, and a flow sensor is set up to measure the leakage cavity. Based on the rotor temperature or leakage, and combined with the Reynolds equation for multiphase flow considering the oil-gas ratio or the contact force model considering surface roughness, the gas film force of the designed contact end face seal is calculated in reverse. The theoretical formula or numerical simulation parameters are selected based on the working conditions under the test conditions, the surface roughness of the sealing surface, and the oil-gas ratio of the sealing medium. Then, the equivalent gas film / liquid film thickness is calculated through the gas film force.

3. The method for predicting the sealing performance of the contact-type end face of the engine-driven pressure groove structure as described in claim 1, characterized in that, The elastic force of the elastic element is greater than the sum of the inertial force of the stationary ring and the axial frictional force of the sealing ring.

4. The method for predicting the sealing performance of the contact-type end face of the engine-driven pressure groove structure as described in claim 1, characterized in that, The compression ratio of the material of the O-ring is controlled between 8% and 12%.

5. The method for predicting the sealing performance of the contact-type end face of the engine-driven pressure groove structure as described in claim 1, characterized in that, The design of the sealing dynamic ring and sealing stationary ring includes material selection for the dynamic ring and stationary ring, design of the clearance between the stationary ring and the housing, design of the flatness and roughness of the sealing end face.

6. The method for predicting the sealing performance of the contact-type end face of the engine-driven pressure groove structure as described in claim 1, characterized in that, The specific method for determining whether the sealing surface is open is as follows: By using the opening force, aerodynamic force, and spring force of the dynamic pressure groove structure, the closing force of the dynamic pressure groove structure is calculated using CFO simulation. The opening force is compared with the closing force. When the opening force is greater than the closing force, it is determined that the sealing surface is open and the parameters need to be readjusted and recalculated. If the opening force is less than the closing force by a certain proportion, it means that the sealing surface is completely closed.

7. The method for predicting the sealing performance of the contact-type end face of the engine-driven pressure groove structure as described in claim 1, characterized in that, The specific method for determining the equivalent gas / liquid film thickness and calculating the structural opening force based on the dynamic pressure groove structure is as follows: obtain the initial geometric clearance of the dynamic pressure groove structure, and calculate the average film thickness h between the sealing surfaces. eq The calculation formula is: h eq =h0+Δh thermal −d roughness −d liquid ; Where h0 is the initial geometric gap, Δh thermal δ represents the change in film thickness due to expansion. roughness δ represents the reduction in film thickness caused by rough peak contact. liquid The thickness of the interstitial space occupied by the liquid phase; The average film thickness h eq The input is placed into a multiphase flow model, and the opening force is calculated through finite element simulation.

Images