摘要
为了研究动静干涉对混流泵内部流动非定常压力脉动特性的影响,在混流泵进口截面、动静耦合面以及出口截面取若干压力脉动监测点,采用RNG k-ε湍流模型和滑移网格技术,对混流泵全流场进行三维非定常湍流计算.计算了叶轮进口截面、动静耦合面以及出口截面的压力脉动,利用快速傅里叶变换进行分析,得到了不同特征截面的压力脉动的频率和幅值,并进行外特性试验验证.结果表明:从轮毂到轮缘,压力脉动最大幅值发生在叶轮出口轮缘侧,而压力脉动最小幅值出现在叶片进口轮毂侧,叶轮进口和叶轮导叶间轮缘处监测点的幅值约为轮毂处监测点幅值的2倍;从叶轮进口到导叶出口位置,压力脉动呈现出逐渐增强的趋势.压力脉动最大值发生在导叶出口监测点,且存在一个低频压力脉动;在60%～85%设计流量工况范围内,扬程-流量特性曲线出现正斜率不稳定特性,数值计算与试验结果存在一定差异.
In order to investigate effects of impeller-guide vane interaction on pressure fluctuation in a low specific speed mixed-flow pump, the three-dimensional, unsteady turbulent flow in it was analyzed by using CFD code with the RNG k -ε turbulence model and sliding mesh technique under the design condition, and the pressure fluctuations at three monitoring points were obtained. Subsequently, the fluctuation signals were transformed into the frequency-domain to get their characteristics in terms of amplitude and frequency. Even though a positive slope head curve was observed under the 60% and 85% design flow rate conditions, the unsteady flow simulation based on the Reynolds-averaged N -S equations failed to show this effect. It was shown that the maximum amplitude of pressure fluctuation is found at the tip of shroud of impeller, but the minimum one was located at the tip of the hub. The am- plitudes of fluctuation at the entrance to impeller and at the monitoring points located at the tip in the gap between impeller and guide were as high as twice the magnitude of the amplitude observed at the tip of hub. Further, the pressure fluctuation exhibited increasing amplitude from the entrance of impel- ler to the outlet to guide vane, where the maximum amplitude with a low frequency was identified.
出处
《排灌机械工程学报》
EI
北大核心
2013年第3期205-209,共5页
Journal of Drainage and Irrigation Machinery Engineering
基金
国家自然科学基金资助项目(51209113)
甘肃省自然科学基金资助项目(2011GS04264)
关键词
混流泵
压力脉动
动静干涉
频谱分析
时频特性
mixed-flow pump
pressure fluctuation
rotor-stator interaction
frequency analysis
time frequency characteristics
