Volumetric efficiency analysis of two-dimensional piston aviation fuel pump

This paper proposes a type of two-dimensional piston fuel pump. The pump uses the rotation motion of the two-dimensional piston to integrate the valve mechanism into the piston, which eliminates the independent valve mechanism of the traditional piston pump, simplifies the structure of the pump, and improves the power density of the pump. At the same time, because the main moving mechanism adopts rolling bearing support, the sliding friction pair and its leakage are avoided, and the efficiency is improved. The volume efficiency of the pump is studied theoretically and experimentally. Combined with the structural principle of the pump, three main causes of volume loss are analyzed, including internal leakage, external leakage, and oil compressibility. Based on the basic theory of laminar and turbulent flow, the analytical expression of leakage is derived, and the internal leakage caused by different port forms is analyzed. Considering the compressibility and leakage of oil, a mathematical model of volumetric efficiency is obtained. The theoretical research shows that the negative opening distribution can effectively reduce the internal leakage, and the relationship between the leakage flow and the negative opening is quantitatively analyzed. At the same time, Fluent is used to simulate the flow field in the pump cavity, and the results show that it can effectively reduce the oil backflow. In order to verify the effectiveness of the theoretical analysis, a two-dimensional piston fuel pump prototype is made, and aviation kerosene is used as the medium for bench test. The experimental results of the prototype show that when the load pressure is 2 MPa, the volumetric efficiency is increased from 93.6% to 98.1% and the rotating speed increased from 1 000 r/ min to 5 000 r/min. When the rotating speed is 2 000 r/min, the load pressure increases from 1 MPa to 5 MPa, and the volumetric efficiency decreases from 97.5% to 92.3%. Compared with the existing gear pump and plunger pump, the volumetric efficiency is significantly improved. The deviation between the theoretical and experimental results is less than 4%, indicating the validity and correctness of the theoretical analysis. © 2020, Press of Chinese Journal of Aeronautics. All right reserved.