不同流量下高速离心泵压力脉动特性分析

Analysis of Pressure Fluctuation Characteristics of High-speed Centrifugal Pump under Different Flow Rate

为掌握高速离心泵内压力脉动变化规律及其脉动源,采用CFX软件对其内部流场进行数值模拟,分析其不同监测点在0.4Qd-1.2Qd（设计流量）的压力脉动特性。研究表明：蜗壳与隔舌的动静干扰是主要的压力脉动源,且在叶轮出口处压力波动幅值最大,其主要频率为叶片通过频率;吸力面的压力要比压力面小,压力面在叶频附近的波动变化区域较大;流量在0.6Qd及以下时,整体压力幅值变化较其他流量时更为剧烈;压力脉动沿流道方向向下游扩散段传递,在蜗壳出口处压力值最小;大流量下的流线较为平滑,而小流量下流线变得紊乱,流量越小流线的扭曲就越严重。

In order to speed centrifugal pumps understand in depth the main influencing factors of pressure pulsation in high- and their variation trends, the internal flow field was numerically simulated by u- sing CFX software and , and each set of monitoring point data was processed by using Fast Fourier Trans- form （FFT）. The characteristics of pressure pulsation were analyzed by investigating the pressure-fre- quency domain and time-domain of different monitoring points at different flow rates from 0.4 to 1.2. Studies showed that the dynamic and static interferences of the volute and the diaphragms are the main source of pressure pulsation, and the amplitude of the pressure fluctuation at the impeller outlet is the largest. The main frequency is the blade passing frequency. The suction surface pressure is smaller than the pressure surface. The pressure fluctuation at the pressure surface is relatively large as close to the blade frequency. With the flow rate of 0.6 or below, the overall pressure amplitude variation is more severe than other flow rates. The pressure pulsation is transmitted to the downstream diffusion section, and the pres- sure reaches minimum at the volute outlet. With high flow rate, the streamline is relatively smooth,while it is distorted under small flow. The smaller the flow rate is, the more serious the distortion of the stream-line is.