CN-121981008-A - Method for predicting volumetric efficiency of pump motor of special equipment in extremely low temperature environment

CN121981008ACN 121981008 ACN121981008 ACN 121981008ACN-121981008-A

Abstract

The invention discloses a method for predicting volumetric efficiency of a pump motor of special equipment in an extremely low temperature environment, which relates to the technical field of hydraulic transmission and comprises the following steps of constructing a pump motor volumetric efficiency parameterized model comprising key auxiliary clearance calculation and leakage flow calculation based on structural parameters, material thermal expansion characteristics and hydraulic oil viscosity-temperature characteristics of the pump motor; the method comprises the steps of obtaining test data of a pump motor under a low-temperature working condition, identifying unknown parameters in a pump motor volumetric efficiency parameterized model by adopting a global optimization algorithm, determining model parameters, inputting running state parameters under a target low-temperature working condition into the pump motor volumetric efficiency parameterized model with the determined parameters, and calculating to obtain a volumetric efficiency predicted value of the pump motor under the corresponding working condition. The invention realizes the reliable prediction of the volumetric efficiency of the pump motor with high precision, high efficiency and low cost under the extremely low temperature environment, and has stronger engineering practicability and popularization value.

Inventors

YU LIANG
ZHENG CHANGSONG
JIA RAN
ZHANG XIAOPENG
BAI CHAOHUI
QIN JINPING
WU WEI
HUANG JIAHAI

Assignees

北京理工大学

Dates

Publication Date: 20260505
Application Date: 20260127

Claims (10)

1. The method for predicting the volumetric efficiency of the pump motor of the special equipment in the extremely low temperature environment is characterized by comprising the following steps: Based on structural parameters, material thermal expansion characteristics and hydraulic oil viscosity-temperature characteristics of the pump motor, constructing a pump motor volumetric efficiency parameterized model comprising key fit auxiliary clearance calculation and leakage flow calculation; acquiring test data of the pump motor under a low-temperature working condition, and identifying unknown parameters in a pump motor volumetric efficiency parameterized model by adopting a global optimization algorithm so as to determine model parameters; And inputting the running state parameters under the target low-temperature working condition into a pump motor volumetric efficiency parameterized model with determined parameters, and calculating to obtain a predicted volumetric efficiency value of the pump motor under the corresponding working condition.
2. The method for predicting volumetric efficiency of a pump motor of a very low temperature environment specialty equipment according to claim 1, wherein constructing a pump motor volumetric efficiency parameterized model comprising key fit sub-clearance calculation and leakage flow calculation specifically comprises: According to the viscosity-temperature characteristic data of the hydraulic oil, establishing an oil characteristic refinement model describing the change of viscosity along with the temperature; calculating the size deformation of the mechanical part due to thermal expansion and contraction according to the material thermal expansion coefficient and the temperature change of the key part; calculating the working clearance variation of a key matching pair of the pump motor at low temperature according to the size deformation, wherein the key matching pair of the pump motor at least comprises an axial matching pair of a cylinder body and a valve plate and a radial matching pair of a plunger and a cylinder hole; Establishing a leakage flow calculation model to calculate total leakage flow based on the working clearance variation, the oil hydrodynamic viscosity determined by the oil characteristic refinement model and the pressure difference of two sides of the matched pair; And establishing a pump motor volumetric efficiency parameterized model according to the total leakage flow and the theoretical flow of the pump motor.
3. The method for predicting the volumetric efficiency of the pump motor of the special equipment in the extremely low temperature environment according to claim 2, wherein the working clearance variation of the key matching pair of the pump motor at the low temperature is calculated according to the dimensional deformation, specifically: when the axial clearance variation of the cylinder body and the valve plate is calculated, calculating according to the difference value of the axial shrinkage of the valve plate and the axial shrinkage of the cylinder body and combining the axial constraint state of the two; When the radial clearance variation between the plunger and the cylinder bore is calculated, the calculation is performed according to half of the difference between the shrinkage of the inner diameter of the cylinder bore and the shrinkage of the outer diameter of the plunger.
4. The prediction method of volumetric efficiency of a pump motor of special equipment in an extremely low temperature environment according to claim 2, wherein the leakage flow calculation model is established based on the working clearance variation, the hydrodynamic viscosity of the oil determined by the oil characteristic refinement model and the differential pressure of two sides of a matched pair, and specifically comprises the following steps: Constructing a first term which is proportional to the third power clearance and the pressure difference and inversely proportional to the dynamic viscosity, a second term which is proportional to the third power clearance and the pressure difference and inversely proportional to the dynamic viscosity, and a third term which is related to the radial clearance and the pump input rotating speed, and carrying out summation treatment on the three terms to obtain a leakage flow calculation model.
5. The method for predicting the volumetric efficiency of the pump motor of the special equipment in the very low temperature environment according to claim 1, wherein the method is characterized by obtaining test data of the pump motor under the low temperature working condition, and identifying unknown parameters in a parameterized model of the volumetric efficiency of the pump motor by adopting a global optimization algorithm, and specifically comprises the following steps: acquiring performance test data of a pump motor when the pump motor runs under typical low-temperature, low-speed and high-torque working conditions, wherein the performance test data at least comprises pump input rotating speed, motor output rotating speed, high-low side pressure, oil liquid temperature and motor output flow; calculating to obtain a volumetric efficiency actual measurement value based on the performance test data, and constructing an adaptability function based on an error between a volumetric efficiency predicted value output by a pump motor volumetric efficiency parameterization model and the volumetric efficiency actual measurement value; And adopting a differential evolution algorithm as a global optimization algorithm, performing iterative optimization on leakage coefficients and clearance parameters included in the pump motor volumetric efficiency parameterized model, and continuously evaluating and screening parameter combinations to minimize the fitness function so as to obtain an optimal parameter solution set.
6. The method for predicting volumetric efficiency of a pump motor of a special equipment in a very low temperature environment according to claim 5, wherein the fitness function is a mean square error of a predicted volumetric efficiency value and an actual volumetric efficiency value, and a regularization constraint term of optimizing parameter amplitude is introduced into the fitness function.
7. A system for predicting volumetric efficiency of a pump motor of a special equipment in a very low temperature environment, characterized by implementing the method of any one of claims 1-6, comprising: The model construction module is used for constructing a pump motor volumetric efficiency parameterized model comprising key fit auxiliary clearance calculation and leakage flow calculation based on structural parameters, material thermal expansion characteristics and hydraulic oil viscosity-temperature characteristics of the pump motor; The parameter identification module is connected with the model construction module and is used for acquiring test data of the pump motor under a low-temperature working condition, and identifying unknown parameters in the pump motor volumetric efficiency parameterized model by adopting a global optimization algorithm so as to determine model parameters; and the efficiency prediction module is connected with the parameter identification module and is used for inputting the running state parameters under the target low-temperature working condition into the pump motor volumetric efficiency parameterized model with determined parameters, and calculating and outputting the volumetric efficiency predicted value of the pump motor under the corresponding working condition.
8. A computer device comprising a memory, a processor and a computer program stored on the memory, characterized in that the processor executes the computer program to carry out the steps of the method according to any one of claims 1-6.
9. A computer readable storage medium, on which a computer program is stored, characterized in that the computer program, when being executed by a processor, implements the steps of the method according to any of claims 1-6.
10. A computer program product comprising a computer program, characterized in that the computer program, when being executed by a processor, realizes the steps of the method according to any one of claims 1-6.

Description

Method for predicting volumetric efficiency of pump motor of special equipment in extremely low temperature environment Technical Field The invention belongs to the technical field of hydraulic transmission, and particularly relates to a method for predicting volumetric efficiency of a pump motor of special equipment in an extremely low temperature environment. Background The pump motor is used as a hydraulic element which integrates the hydraulic pump and the hydraulic motor highly, has the advantages of compact structure, high energy density and the like, and has important application in the field of special equipment, such as a spacecraft hydraulic actuating system in the aerospace field, a high-altitude low-temperature environment aircraft, a polar roaming vehicle in polar scientific investigation equipment, an ice working platform and the like. Volumetric efficiency is a key indicator for measuring the performance of a pump motor and directly reflects the internal leakage and mechanical loss degree of the pump motor in the energy conversion process. At very low temperature (e.g., below-30 ℃) conditions, the volumetric efficiency of the pump motor is affected by the coupling of multiple complications. On one hand, the viscosity of hydraulic oil is increased sharply along with the reduction of temperature, so that the flow resistance is increased, the oil absorption is difficult, and even cavitation is caused, on the other hand, the different metals and nonmetallic materials forming the friction pair have different coefficients of thermal expansion and generate non-uniform shrinkage deformation at low temperature, so that the key fit clearance deviates from the designed optimal value, and the internal leakage is further aggravated. The traditional theory and experience model based on normal temperature condition or simplifying assumption is difficult to accurately describe the multi-factor and nonlinear coupling effect, so that a predicted result has obvious deviation from an actual situation. At present, the main method for acquiring the reliable volumetric efficiency data of the pump motor in a low-temperature environment is to perform physical test by means of a low-temperature environment test bed capable of accurately controlling temperature. However, the method has the defects of high construction cost of a test system, difficult maintenance due to the need of being provided with high-power refrigeration equipment, a special heat-insulating structure and a low-temperature sensor, high energy consumption, long period, long cooling and heat preservation time and low test efficiency in a low-temperature test process, and high test risk due to irreversible damage of a pump motor caused by oil solidification, lubrication failure and the like when cold start or load test is carried out under a real low-temperature condition. Due to the restrictions of the cost, the period and the risk, the existing test can be carried out only under the working conditions of limited temperature points and load, and a complete test data set covering a wide temperature range and all working conditions is difficult to obtain by a system, so that the construction and verification of a high-precision low-temperature performance model are severely restricted. Therefore, there is a lack of a method in the prior art that can predict the volumetric efficiency of a pump motor with high accuracy in extremely low temperature environments based on limited conventional test data or readily available basic characteristic parameters. The method is used for solving the problem of failure of the traditional model at low temperature, reducing the dependence on expensive and high-risk physical tests, and providing a reliable tool for performance evaluation of the pump motor in the design and service stages so as to meet the reliability requirement of special equipment in a severe low-temperature environment. Disclosure of Invention In order to solve the technical problems, the invention provides a method for predicting the volumetric efficiency of a pump motor of special equipment in an extremely low temperature environment, which comprises the following steps: Based on structural parameters, material thermal expansion characteristics and hydraulic oil viscosity-temperature characteristics of the pump motor, constructing a pump motor volumetric efficiency parameterized model comprising key fit auxiliary clearance calculation and leakage flow calculation; acquiring test data of the pump motor under a low-temperature working condition, and identifying unknown parameters in a pump motor volumetric efficiency parameterized model by adopting a global optimization algorithm so as to determine model parameters; And inputting the running state parameters under the target low-temperature working condition into a pump motor volumetric efficiency parameterized model with determined parameters, and calculating to obtain a predicted volumetric efficienc