Cavitation caused by insufficient suction is a major factor that influences the life of aircraft pumps. Currently, pressurizing the tank can solve the cavitation problem under steady largeflow conditions. However, thi...Cavitation caused by insufficient suction is a major factor that influences the life of aircraft pumps. Currently, pressurizing the tank can solve the cavitation problem under steady largeflow conditions. However, this method is not always effective under transient conditions(from zero flow to full flow in a very short time). Moreover, to apply and design other measures, such as a boost impeller, the suction dynamics during the transient period must be investigated. In this paper,a novel approach based on the pressure wave propagation theory is proposed for predicting the inlet pressure of an aircraft pump under transient conditions. First, a dynamic model of a typical aircraft pump is established in the form of differential equations. Then, the transient flow model of the inlet line is described using momentum and continuity equations, and the governing equations are discretized by the method of characteristics and the finite difference method. The simulated results are in good agreement with the results from verification tests. Further simulation analysis indicates that the wave velocity and transient time may influence the inlet and reservoir pressure as well as the size of the inlet line. Finally, solutions for upgrading the inlet pressure are discussed. These solutions provide guidelines for designing inlet installations.展开更多
An integrated boost impeller can effectively improve the suction performance of an aircraft hydraulic pump(AHP).It must be designed very carefully;however,few studies thus far have investigated boost impellers.To expl...An integrated boost impeller can effectively improve the suction performance of an aircraft hydraulic pump(AHP).It must be designed very carefully;however,few studies thus far have investigated boost impellers.To explore the effect of the boost impeller,this study developed a three-dimensional computational fluid dynamics(CFD)model for an AHP based on the k-εturbulence model and full cavitation model.The results of verification tests demonstrated that the model is reliable for simulating the delivery characteristics of piston pumps and the boost capacity of the inlet impeller.Steady-state simulations reveal that the boost impeller can remarkably improve the suction performance and mitigate the cavitation damage due to insufficient fluid filling while only consuming a small proportion of the total input power.Transient-state simulations show that the pump with an impeller is more capable of catching up with a sudden increase in flow demand,and it has a lower suction flow ripple and impact.However,such a boost impeller also has some limitations such as magnifying the suction pressure fluctuation and having little effect on mitigating the cavitation caused by the back-flow jet.展开更多
基金financially supported by the National Natural Science Foundation of China (No. 51775013)
文摘Cavitation caused by insufficient suction is a major factor that influences the life of aircraft pumps. Currently, pressurizing the tank can solve the cavitation problem under steady largeflow conditions. However, this method is not always effective under transient conditions(from zero flow to full flow in a very short time). Moreover, to apply and design other measures, such as a boost impeller, the suction dynamics during the transient period must be investigated. In this paper,a novel approach based on the pressure wave propagation theory is proposed for predicting the inlet pressure of an aircraft pump under transient conditions. First, a dynamic model of a typical aircraft pump is established in the form of differential equations. Then, the transient flow model of the inlet line is described using momentum and continuity equations, and the governing equations are discretized by the method of characteristics and the finite difference method. The simulated results are in good agreement with the results from verification tests. Further simulation analysis indicates that the wave velocity and transient time may influence the inlet and reservoir pressure as well as the size of the inlet line. Finally, solutions for upgrading the inlet pressure are discussed. These solutions provide guidelines for designing inlet installations.
基金financially supported by the National Natural Science Foundation of China(No.51775013)the Science and Technology Research Project of Jiangxi Provincial Department of Education(No.GJJ201914)。
文摘An integrated boost impeller can effectively improve the suction performance of an aircraft hydraulic pump(AHP).It must be designed very carefully;however,few studies thus far have investigated boost impellers.To explore the effect of the boost impeller,this study developed a three-dimensional computational fluid dynamics(CFD)model for an AHP based on the k-εturbulence model and full cavitation model.The results of verification tests demonstrated that the model is reliable for simulating the delivery characteristics of piston pumps and the boost capacity of the inlet impeller.Steady-state simulations reveal that the boost impeller can remarkably improve the suction performance and mitigate the cavitation damage due to insufficient fluid filling while only consuming a small proportion of the total input power.Transient-state simulations show that the pump with an impeller is more capable of catching up with a sudden increase in flow demand,and it has a lower suction flow ripple and impact.However,such a boost impeller also has some limitations such as magnifying the suction pressure fluctuation and having little effect on mitigating the cavitation caused by the back-flow jet.
