Four-layer model for prediction of sand bed height in horizontal gas-liquid stratified flow

Abstract

Gas-liquid stratified flow is the most vulnerable flow regime for sand deposition, owing to the low phase velocities that occur in this flow regime. A theoretical and experimental study is conducted for particle transport in horizontal gas-liquid-solid stratified flow with high particle concentrations.Experimental data are acquired for air, water and spherical glass beads flow with a solid particle concentration of 20,000 PPM. Two particle sizes are utilized, 45–90 μm and 425–600 μm, with superficial liquid velocities of VSL=0.05 and 0.1 m/s and superficial gas velocities of VSG=3.75, 6.7 and 8.6 m/s. Data are acquired for the total particle bed height, demonstrating that it reduces with increasing superficial gas velocity, while increasing with smaller particle size.A new four layer model for gas, liquid, moving bed and stationary bed is proposed for high particle concentrations greater than 10,000 PPM. The gas, liquid and solid particle continuity equations, along with the momentum equations for the gas, liquid and moving bed layers are solved simultaneously, where the stationary particle bed is treated as a boundary. The model enables prediction of the heights and velocities of all four layers. The model predictions for total particle bed height are compared with the experimental data showing a good agreement.