Experimental and Theoretical Study of Interface Characteristics of Gas–Liquid Stratified Flow in Horizontal Pipe at High Pressure

Wave stratified flow is widely encountered in processing industry, the interface wave impacts heat and mass transfer between the fluids, and flow pattern transition from it to slug flow makes it difficult to deal with the processing fluids that transported by long pipelines especially. Meanwhile, the interface wave influences the viscous drag forces working on the fluids in the pipe, which is impacted by the characteristics of interface profile, such as wave length, amplitude and propagation speed. Experiment of air–water two-phase flow in horizontal pipe at different pressures (0.1 MPa, 2 MPa) are carried out, the influence of pressure on interface profile characteristics is studied, new models for wave length, amplitude, frequency and propagation speed are proposed and tested, and good performance is proved. Shear stress working on interface wave is theoretically calculated, influence of both fluids superficial velocities and pressure on it are studied, and its influence on wave propagation speed is formulated.