Transient flow structures and pressure pulsations of a high-pressure aero-fuel centrifugal pump

高压燃油离心泵压力脉动及非定常流动分析

¹ School of Construction Machinery, Chang'an University, Xi'an 710064, China
² School of Power and Energy, Northwestern Polytechnical University, Xi'an 710072, China
³ Shaanxi Aerospace and Astronautics Propulsion Research Institute, Xi'an 710000, China
⁴ China AVIC Xi'an Aero-Engine Controls Technology Co., Ltd, Xi'an 710077, China

Received: 21 March 2021

Abstract

In order to study the complex transient flow characteristics of a high-pressure aero-fuel centrifugal pump within its full working envelope, a certain type of centrifugal pump is numerically simulated, in which the simulation results are compared with the experiment results to verify the effectiveness of the present simulation method. Then, the verified simulation method is selected to analyze the transient flow characteristics, in which the time-frequency characteristic of pressure pulsation at monitored positions is analyzed by using fast fourier transform. In addition, the unsteady flow structures are studied by focusing on the relative speed, turbulent kinetic energy and so on. The results show that the main frequency of pressure pulsation in the impeller and volute is rotation frequency and blade frequency, respectively, where different monitoring points show similar trend. Meanwhile, the flow is relatively stable under design flow rate condition. However, a certain large-scale vortex appears in the impeller channel under small flow rate conditions, which mainly exists at the exit of the impeller channel near the tongue. In addition, turbulent kinetic energy at the exit of the impeller and the tongue has a large distribution range and changes seriously, where a certain hydraulic loss is produced.

摘要

为了掌握全工作包线内高压燃油离心泵的非定常流动特性, 对高压航空燃油离心泵进行了数值模拟并分析其内部的压力脉动及非定常流动变化。将仿真预测结果与泵的性能试验结果进行对比, 验证了所采用的仿真方法的有效性; 对泵内关键位置的压力进行监测, 并利用快速傅里叶变化完成压力脉动的时频特性分析; 重点以相对速度、湍动能等为指标, 分析泵内非定常流动结构的变化。结果表明: 设计流量工况下叶轮流道内压力脉动主频为转频f_n, 蜗壳流道内压力脉动主频为叶频f_b, 不同的监测点均呈现出相似的脉动变化规律。设计流量工况下泵内整体流动相对平稳, 但小流量工况下叶轮流道内出现了一定的漩涡流动, 主要存在于靠近隔舌区域的叶轮流道出口位置。此外, 叶轮出口及隔舌区域的湍动能分布范围较大且变化强烈, 此处存在一定的水力损失。