文丘里高压湿气测量虚高特性数值模拟

Numerical Simulation on High Pressure Wet Gas Flowmetering Overreading Characteristics of Verturi Tube

给出一种高压条件下文丘里湿气虚高的预测方法.该方法基于计算流体动力学离散相模型,对标准文丘里(直径比为0.55,口径15.24,cm)虚高特性进行数值模拟.仿真流体介质为氮气和煤油,工作压力为2,MPa、4,MPa和6,MPa,气相流量为400,m3/h、600,m3/h、800,m3/h和1,000,m3/h,液相流量范围在0～65.11,m3/h之间.数值模拟实验虚高预测结果与英国国家工程实验室高压实流实验数据进行比较,虚高预测值的最大相对误差为5.14%,平均相对误差小于2.8%.同时,将TJU-CFD仿真模型与Steven等7个经典模型的气相流量预测能力进行了比较,在3个压力下,仿真模型依次排序为第2、第4及第3位,最大相对误差小于7.5%,平均误差为2.5%.

A numerical simulation method aimed to predict the overreading characteristics of the Venturi tube subject to high pressure wetness flow was presented. This approach was based on the computational fluid dynamics （CFD） discrete phase model （DPM）. The beta ratio of the standard Venturi tube was 0.55 and the inside diameter was 15.24 cm. Simulated fluid medium was nitrogen and kerosene, and the inlet pressures were 2 MPa, 4 MPa and 6 MPa, which corresponded to the gas flow rate of 400 m3/h, 600 m3/h, 800 m3/h and 1 000 m3/h, respectively, and liquid flow rate was between 0 m3/h and 65.11 m3/h. The results of simulation predicted overreadings caused by wetness were verified by the experimental results of NEL （National Engineering Laboratory） in UK. The maximal relative error of overreading was 5.14%, and the average relative error was less than 2.8%. By comparing the TJU-CFD model with the other classical overreading models on the predicted gas flow rates, the simulation model presented in this paper ranked No.2, No.4 and No.3, respectively, under three individual pressures. The maximal relative error was 7.5%, and the average error was 2.5%.