Calculation and Optimization of Volumetric Efficiency of Aviation External Gear Pump

Abstract

The power consumption of aviation gear pump has a direct impact on the performance of aero-engine. To improve the efficiency of aviation external gear pump, this paper analyses the leakage of gear pump, and calculates the leakage of axial, radial clearance, gear face meshing clearance, and the elastic loss of liquid compression. Mathematical models of volumetric efficiency are established including the effect of temperature and pressure. Comparing the theoretical value with experimental results, the effectiveness of the models is verified with the error less than 5%. On this basis, the design variables of gear pump are optimized with the maximum theoretical displacement as the optimization objective function. The simulation results show significant volumetric efficiency improvement of the external gear pump. And some suggestions on actual products design and analysis in the aviation fuel device are proposed accordingly. External gear pump is widely used in aviation as the main fuel pump, and oil transfer pump, booster pump and return pump of lubricating oil system in aviation power plant, and as the main hydraulic pump in aircraft hydraulic system. With the development of aviation power plant, high-pressure, low pulsation, low noise and large displacement have become the development trend of gear pump [1]. In order to reduce the power consumption of aeroengine, the total efficiency of aero fuel pump is required to be optimized, and the volumetric efficiency of gear pump must be improved accordingly. Various researches in this field mainly studied the improvement of volumetric efficiency and the solution to leakage problem respectively. The method of improving gear pump volumetric efficiency in engineering is studied in [2]. The leakage problem of axial clearance of gear pump is analysed and a new processing technology is proposed in [3]. The mathematical model of leakage in external gear pump is established in [4][5]. And the model of volumetric efficiency of gear pump by experiment is studied in [6][7]. Few studies are taking a holistic view of the problem. Therefore, by establishing and verifying the mathematical model of volume efficiency, the paper proposes a possible integrated method to optimize the volumetric efficiency with theoretical solution to the leakage problem and achieve energy saving consequently.