Abstract：To investigate pressure-flow characteristics of an orifice meter under unsteady or oscillating flow conditions, the size variation of vortices up- and downstream an orifice plate was theoretically analysed when the flow rate was changing. This variation is the main reason for the instantaneous difference in flow rate between the inlet and the outlet of the orifice. An orifice meter model was built, and the pressure-flow characteristics were analysed based on computational fluid dynamic(CFD)method when the inlet flow velocity was imposed by a sine function at a certain frequency. Results indicated that when the inlet flow was in an oscillating state of low frequency, the pressure drop across the orifice was also in an oscillating state with the same frequency but a different phase. The amplitude of pressure drop increased linearly with increasing amplitude of the inlet velocity, and the linear growth coefficient was correlated with the oscillation frequency. There was a transient difference in flow rate between the inlet and the outlet. The greater the oscillation frequency, or the lower the inlet velocity, the smaller the fluctuation of the transient flow rate. Since a phase delay and an instantaneous flow rate difference exists, there is a deviation between the measured flow rate and the actual flow at the outlet, and the higher the oscillation frequency, the larger the deviation.
朱桂华,洪小波*,徐洪威. 振荡流态下孔板流量计的瞬时压力-流量特性分析[J]. 排灌机械工程学报, 2019, 37(3): 237-241.
ZHU Guihua,HONG Xiaobo*,XU Hongwei. Analysis of transient pressure-flow characteristics of an orifice meter in oscillating state. Journal of Drainage and Irrigation Machinery Engin, 2019, 37(3): 237-241.
[1]SHAH M S, JOSHI J B, KALSI A S, et al. Analysis of flow through an orifice meter: CFD simulation[J]. Chemical engineering science, 2012, 71(9):300-309.[2]RANI H P, DIVYA T, SAHAYA R R, et al. Numerical investigation of energy and Reynolds stress distribution for a turbulent flow in an orifice[J]. Engineering failure analysis, 2013, 34(8):451-463.[3]WU Jianhua, AI Wanzheng. Flows through energy dissipaters with sudden reduction and sudden enlargement forms[J]. Journal of hydrodynamics, 2010, 22(3):360-365.[4]纪春华, 朱煜, 徐登峰. 阻尼孔振荡流态下的动态特性分析[J]. 润滑与密封, 2011, 36(10):4-7. JI Chunhua, ZHU Yu,XU Dengfeng.Dynamic characteristic analysis of an orifice in oscillating state[J].Lubrication engineering,2011, 36(10):4-7.(in Chinese)[5]BORUTZKY W, BARNARD B, THOMAJ. An orifice flow model for laminar and turbulent conditions[J]. Simulation modelling practice & theory, 2002, 10(3/4):141-152.[6]ZHAO T S, CHENGP. Experimental studies on the onset of turbulence and frictional losses in an oscillatory turbulent pipe flow[J]. International journal of heat & fluid flow, 1996, 17(4):356-362.[7]HE L, ZHENG G T. Effect of viscous heating in fluid damper on the vibration isolation performance[J]. Mechanical systems & signal processing, 2007, 21(8):3060-3071.[8]AI Wanzheng, WU Jianhua. Comparison on hydraulic characteristics between orifice plate and plug[J]. Journal of Shanghai Jiaotong University(science), 2014,19(4):476-480.[9]NAKAO M, KAWASHIMA K, KAGAWA T. Applica-tion of Mi-simulation using turbulent model for unsteady orifice flow[J]. Journal of fluids engineering, 2008, 131(131):2997-3002.[10]ERDAL A, ANDERSSONH I. Numerical aspects of flow computation through orifices[J]. Flow measurement & instrumentation, 1997, 8(1):27-37.
