Performance Reliability Evaluation Of High-pressure Internal Gear Pump

Internal gear pumps have simple structure,low cost,and easy processing,and are widely used in mechanical industries such as machine tools,ships,aircraft,and automobiles,with a promising development prospect.Pressure is the most important performance parameter of internal gear pumps.With the progress of China’s high-end host equipment technology level,the performance requirements of internal gear pumps under high pressure are constantly increasing.However,the increase in working pressure can cause unstable quality,high early failure rate,and poor reliability of gear pumps.At present,although domestic companies have the production capacity of high-pressure internal gear pumps,there is still a significant gap between domestically produced high-pressure internal gear pumps and foreign products in terms of volumetric efficiency,noise,reliability,and other aspects.This article focuses on the high-pressure internal gear pump and conducts reliability research on its output flow rate,far-field flow-induced noise,and gear pair strength through numerical simulation,dynamics analysis,and reliability theory.The research contents are as follows:(1)Experimental and Simulation Study on the Flow Field and Sound Field of High-pressure Internal Gear PumpExperimental research was conducted on the output flow rate and noise of highpressure internal gear pump.A finite element model of the fluid domain of a highpressure internal gear pump was established,and a simulation strategy was developed to increase the viscosity at the gap to prevent oil backflow in the gear pump under high-pressure conditions.The flow field simulation of a high-pressure internal gear pump considering axial and radial gap leakage was carried out,revealing the distribution patterns of pressure and velocity fields,and exploring the pressure fluctuation characteristics of the high-pressure and low-pressure regions;The distribution pattern of internal flow-induced noise sources was explored through a broadband noise model,and the far-field flow-induced noise was calculated using the acoustic analogy noise model.(2)Reliability evaluation of output flow and far-field flow-induced noise of highpressure internal gear pumpThe influencing factors of output flow and far-field flow-induced noise of highpressure internal gear pump were determined,and the experimental design based on Latin hypercube sampling was carried out.The random parametric simulation was carried out in combination with UG 3D modeling software and Workbench Fluent simulation software.The random response model of output flow and far-field flowinduced noise performance of high-pressure internal gear pump was established using dendrite network,The fourth order moment saddle point approximation method was used to evaluate the reliability of the output flow rate and far-field flow-induced noise of the high-pressure internal gear pump.(3)Reliability evaluation of gear pair strength for high-pressure internal gear pumpA nonlinear dynamic model of internal gear pair was established,and the dynamic response characteristics of displacement,velocity,and acceleration of the external gear and inner gear ring were revealed.The dynamic meshing force of the gear pair was obtained through dynamic analysis,and the dynamic contact stress and dynamic bending stress at the tooth root were calculated.The factors affecting the strength of the gear pair of the internal gear pump were determined.The maximum tooth surface contact stress and the maximum tooth root bending stress were taken as responses,and a stochastic response model of the gear pair strength performance of the high-pressure internal gear pump was established.The performance reliability of the gear surface contact strength and tooth root bending strength of the high-pressure internal gear pump was evaluated.This article conducts a performance reliability study on the output flow rate,farfield flow-induced noise,and gear pair strength of the high-pressure internal gear pump.The reliability variation curve of the high-pressure internal gear pump under operating conditions of 1500r/min speed and 25 MPa working pressure is obtained.Based on this,further research on the reliability sensitivity of the high-pressure internal gear pump can be carried out,and the structural optimization design of the high-pressure internal gear pump can be achieved.The thesis has 60 pictures,12 tables and 94 references.