Pressure fluctuation and its influencing factors in circulating water pump
来源期刊：中南大学学报(英文版)2013年第1期
论文作者：DAI Cui(代翠) KONG Fan-yu(孔繁余) DONG Liang(董亮)
文章页码：149 - 155
Key words：circulating water pump; turbulence model; sampling frequency; sampling time; pressure fluctuation
Abstract: In order to investigate the effect of sampling frequency and time on pressure fluctuations, the three-dimensional unsteady numerical simulations were conducted in a circulating water pump. Through comparison of turbulence models with hydraulic performance experiment, SST k-ω model was confirmed to study the rational determination of sampling frequency an, d time better. The Fast Fourier Transform (FFT) technology was then adopted to process those fluctuating pressure signals obtained. On these bases, the characteristics of pressure fluctuations acting on the tongue were discussed. It is found that aliasing errors decrease at higher sampling frequency of 17 640 Hz, but not at a lower sampling frequency of 1 764 Hz. Correspondingly, an output frequency range ten-times wider is obtained at 17 640 Hz. Compared with 8R, when the sampling time is shorter, the amplitudes may be overvalued, and the frequencies and amplitudes of low-frequency fluctuations can not be well predicted. The frequencies at the tongue are in good agreement with the values calculated by formula and the frequency compositions less than the blade passing frequency are accurately predicted.
DAI Cui(代翠), KONG Fan-yu(孔繁余), DONG Liang(董亮)
(Research Center of Fluid Machinery Engineering and Technology, Jiangsu University, Zhenjiang 212013, China)
Abstract:In order to investigate the effect of sampling frequency and time on pressure fluctuations, the three-dimensional unsteady numerical simulations were conducted in a circulating water pump. Through comparison of turbulence models with hydraulic performance experiment, SST k-ω model was confirmed to study the rational determination of sampling frequency an, d time better. The Fast Fourier Transform (FFT) technology was then adopted to process those fluctuating pressure signals obtained. On these bases, the characteristics of pressure fluctuations acting on the tongue were discussed. It is found that aliasing errors decrease at higher sampling frequency of 17 640 Hz, but not at a lower sampling frequency of 1 764 Hz. Correspondingly, an output frequency range ten-times wider is obtained at 17 640 Hz. Compared with 8R, when the sampling time is shorter, the amplitudes may be overvalued, and the frequencies and amplitudes of low-frequency fluctuations can not be well predicted. The frequencies at the tongue are in good agreement with the values calculated by formula and the frequency compositions less than the blade passing frequency are accurately predicted.
Key words:circulating water pump; turbulence model; sampling frequency; sampling time; pressure fluctuation
