含气率对离心式航空燃油泵叶片压力脉动的影响

为研究含气率对某分流叶片式航空燃油泵叶片的压力脉动规律,基于RNG k-ε湍流模型和Euler-Euler非均相模型,应用ANSYS CFX软件对航空燃油泵在不同含气率条件下进行数值计算,分析燃油泵的气相分布和叶片压力脉动规律.研究结果表明:气相主要分布在叶片的压力面,吸力面分布较少;随着含气率的增大,气相逐渐向长短叶片吸力面发展,并扩散至叶轮流道;在长叶片前段相对位置0~0.5处,气相体积占比随含气率的增大而增大,在长叶片压力面后段(相对位置0.5~1.0处)和短叶片压力面上气相占比几乎为100%,产生气液分离,在长叶片吸力面后端和短叶片吸力面上,气相占比较少,几乎为0;通入气相会使监测点压力脉动幅值变大,但含气率继续增大会降低燃油泵叶片压力脉动幅值;长叶片的中段和短叶片前段的主导频率受含气率的影响会发生改变,由于分流式叶片的设计结构,含气率对叶片压力脉动影响主要体现在流动最为复杂的长短叶片的交界面处即短叶片的进口位置;分流叶片在改善流动的同时,也会影响相应位置的压力脉动.研究结果可为分流叶片式燃油泵设计提供一定技术参考.

Influence of air void fraction on pressure fluctuation of centrifugal aviation fuel pump blade

In order to investigate the effect of air void fraction on the pressure fluctuation of a split vane aviation fuel pump blade, the numerical calculation of the aviation fuel pump under different air void fraction conditions was performed using the ANSYS CFX software. The laws of gas phase distribution and the fuel pump′s blade pressure pulsation was analyzed. The results show that the gas phase is mainly distributed on the pressure surface of the blade and less on the suction surface. With the void fraction increases, the gas phase develops on the suction surfaces of the long and short blades, and diffuses into the impeller passage. At the relative position 0-0.5 of the front section of the long blade, the proportion of the gas phase volume increases with the increase of the gas content. At the rear section(relative position 0.5-1.0)of the pressure surface of the long blade and the pressure surface of the short blade, the proportion of the gas phase is almost 100%, resulting in gas-liquid separation. On the rear end of the long blade suction surface and the short blade suction surface, the gas phase accounts for almost 0. The gas phase will increase the amplitude of pressure fluctuation at the monitoring point. However, as the void fraction increases, the amplitude of pressure fluctuations at fuel pump blades decrease. The dominant frequencies of the middle section of the long blade and the front section of the short blade will change due to the influence of the void fraction. Due to the design structure of split blades, the influence of void fraction on blade pressure pulsation is mainly reflected at the interface between long and short blades with the most complex flow. The splitter blade can not only improve the flow, but also affecting the pressure pulsation at the corresponding locations. The research results can provide some reference for the design of split vane fuel pump.