黏度对垂直管气液两相流压降的影响

The Influence of Viscosity on Pressure Drop of Gas-liquid Two-phase Flow in Vertical Pipe

压降是气液两相流研究中的重要参数,而黏度对气液两相流压降有显著影响,因此有必要对不同黏度下压降规律进行研究。采用多相流试验平台测试系统,在内径60 mm,实验段长8 m的垂直管中开展油气两相流实验研究。表观液速 0.08~ 0.20 m/s,表观气速1~19 m/s,气相为空气,液相为白油,黏度分别为25、50、70、150、200 mPa ·s,研究黏度对压降以及Beggs-Brill、Mukherjee-Brill和Hasan-Kabir三种压降模型计算准确性的影响。结果显示:压降模型的计算精度绝大部分会随黏度的增加而降低,其中Beggs-Brill模型在不同黏度下准确度较其他两种更为稳定,但黏度在200 mPa ·s时绝对误差高达42.67%;黏度对于总压降影响明显,而对位差压降的影响较小;实验中观察到负摩阻压降现象,发现表观气液速度越小,黏度对负摩阻压降影响越大。

Pressure drop is an important parameter in gas-liquid two-phase flow study, and viscosity has a significant influence on pressure drop of gas-liquid two-phase flow. Therefore, it is necessary to research the law of pressure drop with different viscosities. The two-phase flow experiment is carried out in a vertical pipe of 60 mm diameter and 8 m in length. The superficial liquid velocity is from 0.08 to 0.20 m/s,and the superficial gas velocity is from 1 to 19 m/s. Air and mineral oil are used as the fluids.Viscosities of the oil are 25, 50, 70, 150 and 200 mPa ·s . The multiphase flow test platform is used to research the effect of viscosity on pressure drop and the accuracy of three pressure prediction models (Beggs-Brill,Mukherjee-Brill and Hasan-Kabir) respectively. The results show that accuracy of pressure drop calculation mostly decrease with the increase of liquid viscosity, and the accuracy of Beggs-Brill model is more stable than the other two models at different viscosities, but the absolute average error reached 42.67% at 200 mPa ·s.And viscosity has a significant effect on the total pressure drop, but little effect on the pressure drop of the potential difference. The phenomenon of negative frictional pressure drop is observed in the experiment. The result shows that the smaller the superficial gas velocity is, the greater the influence of viscosity on the negative frictional pressure drop.