Pressure fluctuation of solid-liquid flow in stator and rotor cascades of pump as turbine
HAN Wei1,2, LI Xuefeng1,2*, SU Min3, LI Rennian1,2, CHEN Hao1,2
1.School of Energy and Power Engineering, Lanzhou University of Technology, Lanzhou, Gansu 730050, China; 2.Gansu Key Laboratory of Fluid Machinery and System, Lanzhou, Gansu 730050, China; 3.College of Electrical and Information Engineering, Lanzhou University of Technology, Lanzhou, Gansu 730050, China
Abstract:In order to study the pressure fluctuation characteristics of solid-liquid flow in stator and rotor cascades of pump as turbine, the centrifugal pump with space diffuser as turbine is chosen, and then the unsteady 3D flow field was simulated based on the large-eddy simulation(LES)and Mixture multiphase flow model with structured hexahedral mesh generated in ICEM. The pressure fluctuations under three different flow in water and solid-liquid two-phase were monitored in the numerical calculation. The results showed that the point P3 between the stator and the rotor and the point P6 in the guide vane are due to the pressure gradient alternating change in the impeller under the water and solid-liquid two-phase, the periodicity of the pressure fluctuations in time domain is obvious, and consis-tent with the blade passing period. The presence of particles reduces the backflow of the draft tube, which makes the pressure fluctuation more stable at the small flow rate, and the existence of particles increases the flow field disturbance at the large flow rate. The results of the pressure fluctuations in frequency domain reveal that the main frequency are of the blade passing frequency(BPF)and the harmonic frequency is a multiple of the blade passing frequency at different conditions, and its amplitude shows exponential decay. The vortex induces second-harmonic in the impeller obviously. The particles enhance the high-frequency pressure fluctuation at the small flow rate while those weaken it at the large flow rate.
韩伟,, 李雪峰,*, 苏敏, 李仁年,, 陈昊,. 透平工况动静叶栅内固液两相流动压力脉动特性[J]. 排灌机械工程学报, 2018, 36(2): 99-103.
HAN Wei,, LI Xuefeng,*, SU Min, LI Rennian,, CHEN Hao,. Pressure fluctuation of solid-liquid flow in stator and rotor cascades of pump as turbine. Journal of Drainage and Irrigation Machinery Engin, 2018, 36(2): 99-103.
[1]朱荣生, 龙云, 付强,等. 核主泵小流量工况压力脉动特性[J]. 振动与冲击, 2014, 33(17):143-149. ZHU Rongsheng,LONG Yun,FU Qiang,et al. Pressure pulsation of a reactor coolant pump under low flow conditions[J].Journal of vibration and shock,2014,33(17):143-149.(in Chinese)[2]杨孙圣, 孔繁余, 成军,等. 液力透平蜗壳内非定常压力脉动的研究[J]. 工程力学, 2013,30(2):388-393. YANG Sunsheng,KONG Fanyu,CHENG Jun,et al. Reseach on unsteady pressure field within a hydraulic turbine volute[J].Engineering mechanics,2013,30(2):388-393.(in Chinese)[3]YANG Sunsheng, KONG Fangyu, QU Xiaoyu, et al. Influence of blade number on the performance and pressure pulsations in a pump used as a turbine[J]. Journal of fluids engineering, 2012, 134(12):67-75.[4]杨孙圣. 离心泵作透平的理论分析数值计算与实验研究[D]. 镇江:江苏大学, 2012.[5]史广泰, 杨军虎, 苗森春,等. 不同进口截面下液力透平非定常压力脉动计算[J]. 航空动力学报, 2016, 31(3):659-668. SHI Guangtai, YANG Junhu, MIAO Senchun, et al. Unsteady calculation of pressure pulsations within hydraulic turbine under different entrance sections [J]. Journal of aerospace power, 2016, 31(3):659-668.(in Chinese)[6]史广泰, 杨军虎, 苗森春,等. 不同导叶数下液力透平蜗壳内压力脉动计算[J]. 航空动力学报, 2015, 30(5):1228-1235. SHI Guangtai., YANG Junhu., MIAO Senchun. et al. Calculation of pressure fluctuation within volute of hydraulic turbine under different guide vane numbers [J]. Journal of aerospace power, 2015, 30(5):1228-1235.(in Chinese)[7]夏勇,王春林,杨晓勇,等. 双吸泵作液力透平内部流动诱导噪声数值分析[J]. 排灌机械工程学报, 2016, 34(6):483-489. XIA Yong, WANG Chunlin, YANG Xiaoyong, et al. [J]. Journal of drainage & irrigation machinery engineering, 2016, 34(6):483-489.(in Chinese)[8]代翠,董亮,孔繁余,等. 泵作透平振动噪声机理分析与试验[J]. 农业工程学报, 2014,30(15):114-119. DAI Cui, DONG Liang, KONG Fangyu,, et al. Mechanism analysis of vibration and noise for centrifugal pump working as turbine[J]. Transactions of the CSAE, 2014, 30(15):114-119.(in Chinese)[9]夏书强. 气液两相介质下液力透平基本方程和换算关系曲线的研究[D]. 兰州:兰州理工大学, 2013.[10]黄思, 陈宇, 宿向辉. 离心泵作水力透平起动过程的非定常流场模拟计算[J]. 水泵技术, 2015(5):25-30. HUANG Si, CHEN Yu, SU Xianghui. Unsteady flow field simulation of centrifugal pump for starting process of hydraulic turbine [J]. Pump technology, 2015(5):25-30.(in Chinese)[11]XIAO Huahua, MAO Zhanli, AN Weiguang, et al. Experimental and LES investigation of flame propagation in a hydrogen/air mixture in a combustion vessel[J]. Chinese science bulletin,2014(20):2496-2504.[12]MAJIDI K. Numberical study of unsteady flow in a centrifugal pump [J]. Journal of turbomachinery, 2005, 127(2):363-371.