Simulation calculation method of engine bearing cavity ventilation system considering pump suction performance

Abstract

The invention belongs to the technical field of aviation, and particularly relates to an engine bearing cavity ventilation system simulation calculation method considering pump suction performance, which is based on a flow simulation calculation platform and adopts elements such as a cylindrical pipeline, an elbow, a transition joint, a throttling hole, a flow source, a pressure source, a controller and a signal collector. Components such as a pipeline, a sealing device, a bearing cavity and a lubricating oil pump set are represented, an engine bearing cavity ventilation system simulation calculation model considering pump suction characteristics is constructed, parameters such as pressure and ventilation quantity of the bearing cavity can be accurately calculated, and the influence mechanism of the parameters such as structures, flow, pressure and throttling hole diameters of different components on the ventilation system is revealed. According to the scheme, modular elements are adopted, the system layout and related parameters can be conveniently and rapidly adjusted, the design accuracy and calculation efficiency of the bearing cavity scheme are improved, and the high cost generated by redeveloping a new ventilation system is reduced.

Description

Technical Field

[0001] This application belongs to the field of aerospace technology, and specifically relates to a simulation calculation method for an engine bearing cavity ventilation system that takes into account pump suction performance. Background Technology

[0002] High-temperature and high-speed operating conditions place high demands on the working environment of engine bearings, thus requiring lubricating oil to remove the heat generated by the high-speed rotation and friction of the bearings. To prevent lubricating oil leakage from the bearing cavity and ensure that the pressure in the bearing cavity remains within the normal range, a reasonable ventilation system must be designed to guarantee a sufficient sealing pressure difference.

[0003] Traditional simulation calculation methods for engine bearing cavity ventilation systems only consider the effects of components such as straight pipes, throttle orifices, seals, and ventilators in the lubricating oil system, without considering the impact of gas drawn in by the lubricating oil pump group on the ventilation system. This leads to discrepancies between the calculated pressure and ventilation volume results and the actual test results.

[0004] Currently, existing simulation calculation methods for engine bearing cavity ventilation systems have the following drawbacks in use:

[0005] 1. Traditional simulation calculation methods for ventilation systems do not consider the impact of the gas drawn in by the lubricating oil pump group on the ventilation system, and have an unclear understanding of the flow mechanism inside the ventilation system. This leads to deviations between the calculated pressure and ventilation volume results and the actual test results, and the design results cannot meet the usage requirements. This often results in repeated iterations of the scheme, which is costly and inefficient.

[0006] 2. Traditional ventilation system simulation calculation methods use programming languages. If the scheme or parameters are adjusted, the underlying code needs to be modified. This results in low efficiency in scheme design and improvement, poor generalization, and an inability to quickly and efficiently complete simulation calculations for multiple schemes.

[0007] Therefore, how to perform simulation calculations of ventilation systems more effectively is a problem that needs to be solved. Summary of the Invention

[0008] The purpose of this application is to provide a simulation calculation method for an engine bearing cavity ventilation system that takes into account pump suction performance, so as to solve the problem of low efficiency in existing ventilation system simulation calculations.

[0009] The technical solution of this application is: a simulation calculation method for an engine bearing cavity ventilation system considering pump suction performance, including:

[0010] The composition of the ventilation system network model and data measurement points are determined based on the current bearing cavity ventilation system structure.

[0011] A ventilation system network model is built based on the composition and data measurement points of the ventilation system network model, and a graphite seal simulation calculation model is built on the basis of the sealing leakage formula.

[0012] Set the model parameters and initial bearing cavity pressure, run the ventilation system network model, and then calculate the bearing cavity pressure output value based on the operational data collected from the data measurement points; the operational data includes bearing cavity pressure, sealing pressure difference, and system flow rate;

[0013] Determine whether the initial bearing cavity pressure meets the design requirements based on the bearing cavity pressure output value and the initial bearing cavity pressure value. If yes, proceed to the next step; otherwise, reset the initial bearing cavity pressure value.

[0014] Determine whether the bearing cavity pressure, sealing pressure difference, and system flow rate meet the design requirements. If yes, output the front cavity sealing pressure difference results corresponding to different front cavity ventilation throttle nozzle inner diameters. If not, rebuild the ventilation system network model.

[0015] Preferably, the ventilation system network model includes cylindrical pipes, elbows, transition joints, throttling orifices, flow sources, pressure sources, controllers, and signal acquisition devices.

[0016] Preferably, when (bearing cavity pressure output value - bearing cavity pressure initial value) / bearing cavity pressure initial value ≤ 1%, it is determined whether the bearing cavity pressure initial value meets the design requirements.

[0017] Preferably, bearing cavity pressure, sealing pressure difference, and system flow rate thresholds are set, and the bearing cavity pressure, sealing pressure difference, and system flow rate are compared with the bearing cavity pressure, sealing pressure difference, and system flow rate thresholds, respectively. If all are within the corresponding threshold range, the design requirements are deemed met.

[0018] Preferably, the model parameters include environmental parameters, medium property parameters, basic component parameters, sealing bleed pressure, bearing cavity boundary pressure, and lubricating oil pump group suction flow rate.

[0019] Preferably, when building the graphite seal simulation calculation model, the inputs are the gas chamber temperature T, the gas chamber pressure P1, the oil chamber pressure P2, and the output is the oil chamber pressure P2'. When the leakage formula is satisfied, the system is considered to have reached a balanced state, and the outputs are the bleed air flow rate and pressure drop parameters.

[0020] This application presents a simulation calculation method for an engine bearing cavity ventilation system considering pump suction performance. Based on a flow simulation calculation platform, it employs components such as cylindrical pipes, elbows, transition joints, throttling orifices, flow sources, pressure sources, controllers, and signal acquisition devices to characterize components such as pipelines, sealing devices, bearing cavities, and lubricating oil pump units. This constructs a simulation calculation model of the engine bearing cavity ventilation system considering pump suction characteristics, which can accurately calculate parameters such as bearing cavity pressure and ventilation volume, revealing the influence mechanism of different component structures, flow rates, pressures, and throttling orifice diameters on the ventilation system. The use of modular components allows for convenient and quick adjustments to the system layout and related parameters, improving the accuracy and calculation efficiency of bearing cavity design and reducing the high costs associated with developing a new ventilation system. Attached Figure Description

[0021] To more clearly illustrate the technical solutions provided in this application, the accompanying drawings will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application.

[0022] Figure 1 This is a schematic diagram of the overall process of this application;

[0023] Figure 2 This is a schematic diagram of the ventilation system of this application;

[0024] Figure 3 This is a schematic diagram of the ventilation system network model of this application;

[0025] Figure 4 This is a schematic diagram of the simulation calculation results of this application. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] A simulation calculation method for an engine bearing cavity ventilation system that considers pump suction performance is proposed. Taking the engine front bearing cavity ventilation system as the research object, the method of considering pump suction performance is used to simulate the ventilation system.

[0028] like Figure 1 As shown, it includes the following steps:

[0029] Step S100: Determine the composition of the ventilation system network model and the data measurement points based on the current bearing cavity ventilation system structure.

[0030] The bearing cavity ventilation system consists of several parts, including bearing cavity ventilation (including bearing cavity ventilation throttle nozzles), bearing cavity evacuation (including sealing devices), and bearing cavity oil return (including lubricating oil pump unit bearing cavity oil return stage air extraction). Figure 2 .

[0031] Step S200: Based on the composition and data measurement points of the ventilation system network model, a ventilation system network model is built, and based on the sealing leakage formula, a graphite sealing simulation calculation model is built on the ventilation system network model.

[0032] The ventilation system network model includes components such as cylindrical ducts, elbows, transition joints, throttling orifices, flow sources (oil pump sets, etc.), pressure sources (sealing boundaries, bearing cavity boundaries, etc.), controllers, and signal acquisition devices to build the system model. (See attached image.) Figure 3 See Table 1.

[0033] Table 1 Component Model Reference List

[0034] Serial Number Name Element 1 Lubricating oil pump set Source: Flow 2 Sealing boundary, bearing chamber boundary, etc. Source: Pressure 3 Sealing device Controller: Signal Generator, Gauge Template, Controller Template, Pipe: Cylindrical and Generic Component 4 Flow resistance unit Loss: Discrete 5 Cylindrical pipe Pipe: Cylindrical 6 Elbow Bend: Circular 7 External mitre elbow Bend: Circular Mitre 8 T-junction Junction: T 9 Y-junction Junction: Y 10 Gradual transition joint Transition: Gradual 11 Abrupt transition joint Transition: Abrupt 12 Long orifice Orifice: Long 13 Sharp-edged (conical) orifice Pressure, temperature signal source 14 Signal Generator (Tabular) Signal branch 15 Signal Splitter Figure 4

[0035] Preferably, when building the graphite seal simulation calculation model, the inputs are the gas chamber temperature T, the gas chamber pressure P1, the oil chamber pressure P2, and the output is the oil chamber pressure P2'. When the leakage formula is satisfied, the system is considered to have reached a balanced state, and the outputs are the bleed air flow rate and pressure drop parameters.

[0036] Step S300: Set the model parameters and the initial value of the bearing cavity pressure, run the ventilation system network model, and then calculate the bearing cavity pressure output value based on the operating data collected from the data measurement points; the operating data includes the bearing cavity pressure, sealing pressure difference and system flow rate.

[0037] The specific model parameter settings are: environmental parameters, medium property parameters, basic component parameters, sealing bleed pressure, bearing cavity boundary pressure, lubricating oil pump group suction flow rate, and other parameters.

[0038] Step S400: Determine whether the initial bearing cavity pressure meets the design requirements based on the bearing cavity pressure output value and the initial bearing cavity pressure value. If yes, proceed to the next step; otherwise, reset the initial bearing cavity pressure value.

[0039] Preferably, the specific method for determining whether the initial pressure value of the bearing cavity meets the design requirements is as follows:

[0040] When (bearing cavity pressure output value - bearing cavity pressure initial value) / bearing cavity pressure initial value ≤ 1%, determine whether the bearing cavity pressure initial value meets the design requirements. 1% can be adjusted according to the actual situation.

[0041] Step S500: Determine whether the bearing cavity pressure, sealing pressure difference, and system flow rate meet the design requirements. If yes, output the front cavity sealing pressure difference results corresponding to different front cavity ventilation throttle nozzle inner diameters. If not, rebuild the ventilation system network model.

[0042] Finally, the results of the front cavity sealing pressure difference corresponding to different bearing cavity ventilation throttle nozzle inner diameters were obtained, see... ​ The simulation calculation error has been verified to be less than 3%, and this method can guide the design of bearing cavity ventilation systems.

[0043] In summary, this application has the following advantages:

[0044] 1. Based on a flow simulation computing platform, various components are used to characterize parts such as pipelines, sealing devices, bearing cavities, and lubricating oil pump sets. A simulation calculation model of the engine bearing cavity ventilation system considering pump suction characteristics is constructed. The model can accurately calculate parameters such as bearing cavity pressure and ventilation volume, and reveal the influence mechanism of different component structures, flow rates, pressures, throttling orifice diameters on the ventilation system.

[0045] 2. The use of modular components allows for convenient and quick adjustments to the system layout and related parameters, improving the accuracy and calculation efficiency of the bearing cavity design and reducing the high costs associated with developing a new ventilation system.

[0046] Finally, it should be noted that the accompanying drawings of the embodiments disclosed in this invention only involve the structures involved in the embodiments disclosed in this invention. Other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of this invention can be combined with each other.

[0047] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A simulation calculation method for an engine bearing cavity ventilation system considering pump suction performance, characterized in that, include: The composition of the ventilation system network model and data measurement points are determined based on the current bearing cavity ventilation system structure. A ventilation system network model is built based on the composition and data measurement points of the ventilation system network model, and a graphite seal simulation calculation model is built on the basis of the sealing leakage formula. Set the model parameters and initial bearing cavity pressure, run the ventilation system network model, and then calculate the bearing cavity pressure output value based on the operational data collected from the data measurement points; the operational data includes bearing cavity pressure, sealing pressure difference, and system flow rate; Determine whether the initial bearing cavity pressure meets the design requirements based on the bearing cavity pressure output value and the initial bearing cavity pressure value. If so, proceed to the next step. If not, reset the initial bearing cavity pressure value; Determine whether the bearing cavity pressure, sealing pressure difference, and system flow rate meet the design requirements. If yes, output the front cavity sealing pressure difference results corresponding to different front cavity ventilation throttle nozzle inner diameters. If not, rebuild the ventilation system network model.

2. The simulation calculation method for an engine bearing cavity ventilation system considering pump suction performance as described in claim 1, characterized in that, The ventilation system network model includes cylindrical ducts, elbows, transition joints, throttling orifices, flow sources, pressure sources, controllers, and signal acquisition devices.

3. The simulation calculation method for an engine bearing cavity ventilation system considering pump suction performance as described in claim 1, characterized in that, When (bearing cavity pressure output value - bearing cavity pressure initial value) / bearing cavity pressure initial value ≤ 1%, determine whether the bearing cavity pressure initial value meets the design requirements.

4. The simulation calculation method for an engine bearing cavity ventilation system considering pump suction performance as described in claim 1, characterized in that, Set the bearing cavity pressure, sealing pressure difference, and system flow rate thresholds. Compare the bearing cavity pressure, sealing pressure difference, and system flow rate with the corresponding thresholds. If all are within the corresponding threshold range, the design requirements are deemed met.

5. The simulation calculation method for an engine bearing cavity ventilation system considering pump suction performance as described in claim 1, characterized in that, The model parameters include environmental parameters, medium physical property parameters, basic component parameters, sealing bleed pressure, bearing cavity boundary pressure, and lubricating oil pump group suction flow rate.

6. The simulation calculation method for an engine bearing cavity ventilation system considering pump suction performance as described in claim 1, characterized in that, When building a graphite seal simulation model, the inputs are the gas chamber temperature T, gas chamber pressure P1, and oil chamber pressure P2, and the output is the oil chamber pressure P2'. When the leakage formula is satisfied, the system is considered to have reached a balanced state, and the output parameters are the bleed air flow rate and pressure drop.

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