Heat transfer in horizontal plug and slug flow for gas-liquid and gas-slurry systems.

Abstract

Heat transfer coefficients and flow characteristics were measured in a horizontal loop of 51.5 mm diam. pipe. The viscosities of liquid and slurry were changed in the range of 0.8-55 mPa •.s. The experiments were carried out in the regimes of plug and slug flow. The pressure drop in the straight sections was smaller than that predicted by the Lockhart-Martinelli correlation and was correlated by a newly proposed equation. The gas holdup increased with increasing gas velocity and decreasing liquid or slurry velocity. A correlation of the gas holdup is presented. The heat transfer coefficients, h, increased with increasing liquid velocity and decreased with increasing liquid viscosity. In the range of the superficial gas velocity Ug=0.2-1 m•s-1, h was nearly independent of the gas velocity. In the range of Ug=1-10m•s-1, however, h increased with increasing gas velocity. The values of h in the present experiments as well as those in the literature are well described by the equation proposed in this work.