利用涡街流量计测量油水两相流流量

Oil-water two-phase flow measurement using vortex flowmeter

为了考察涡街流量计在油水两相流中的测量特性,在内径为50 mm的垂直上升管道内,对不同混合流量、含油率下的涡街信号进行了实验测量,并对油水两相仪表系数和斯特劳哈尔数予以分析。结果表明,在含油率5%～40%内,仪表系数相对误差小于4%,斯特劳哈尔数相对误差随含油率增加有变大趋势、随混合流量增加有减小趋势,而且在两相雷诺数2×104～5×104内可视为常数,并随雷诺数降低而升高。实验说明油水两相流中存在稳定的两相涡街,利用涡街流量计测量油水两相混合流量具有可行性。

To evaluate the performance of vortex flowmeter in oil-water two-phase flow, vortex signals are detected under different mixture flow rates and the oil volume fraction in a vertical upward pipe with a diameter of 50 mm and analyzed in terms of the meter coefficient and the Strouhal number in oil-water two-phase flow. The result shows that the relative error of meter coefficient is within 4% as oil fractions vary from 5% up to 40% in volume, and the Strouhal relative error increases as oil volume fraction increases or mixture flow rate decreases. It is also found that Strouhal number in oil-water two-phase flow is approximate a constant during the Reynolds number from 2 ×10^4～5×10^4, and increases when the Reynolds number deceases beyond that range. The results show that there exist steady two-phase vortex streets in oil-water two-phase flow and it is feasible to measure the mixture flow rate of oilwater two-phase flow using a vortex flowmeter.