基于文丘里管和射线技术的高压湿气虚高修正

Overreading Correction of High Pressure Wet Gas Flowrate Measurement Based on Venturi Meter and Gamma Ray Technology

为了修正仅用单一节流件测量湿气时因液相存在而导致测量结果虚高的问题,利用水平文丘里管结合伽马射线技术开展了理论分析和实验研究。实验系统管道直径254 mm,实验工质气相为氮气,液相为煤油。水平安装的文丘里管入口内径为172 mm,直径比为0.58,以喉部设置的伽马射线测量装置测量截面含气率。考虑干度和气液滑速比的影响,基于实验数据进行非线性拟合,提出了新的虚高修正计算模型,并将新模型计算结果同Murdock和Chisholm虚高修正模型进行了对比分析,结果表明:Murdock和Chisholm模型仅能在Lockhart-Martinelli参数位于0.001~0.1的范围内时,与虚高具有高精度线性关系,而新模型能够在Lockhart-Martinelli参数位于0.001~0.275的范围内时,始终与虚高具有高精度线性关系。新模型所需参数均可现场实时测量,具有计算简便、适用范围更宽的特点。

Theoretical analysis and experiments based on horizontally installed Venturi flow meter and gamma ray sensor are carried out to correct the overreading of wet gas flow measurement caused by the existence of liquid with single differential pressure flow meter.The pipe diameter of experiment is 254 mm,test mediums are nitrogen for gas phase and kerosene for liquid phase.The inlet diameter of Venturi is 172 mm and diameter ratio is 0.58.The gamma sensor is installed at the throat of Venturi for gas void fraction measurement.The quality and gas liquid slip ratio are considered to nonlinearly fit the test data,and a new empirical correction model is obtained.Calculation results from the new model are compared with the results from modes of Murdock and Chisholm.Experimental results show that the overreading corrections calculated by the traditional Murdock and Chisholm models keep high accuracy only when Lockhart-Martinelli parameter ranges from 0.011 to 0.1,while the new empirical correction model keeps linear relationship with overreading in a larger range of Lockhart-Martinelli parameter from 0.011 to 0.275.Parameters of the new model are easy to be measured and adapts to larger range of Lockhart-Martinelli,and is more suitable for practical use.