Numerical investigation of multiphase flow in supersonic separator considering inner body effect

This paper presents research on the supersonic nozzle geometry with particular emphasis on the effect of the internal body of the nozzle that largely affects the separation efficiency. A numerical investigation of the supersonic nozzle with an internal solid body, which forms an annular flow inside the convergent-divergent nozzle is carried out. The present study revealed different hydrodynamic behaviors of the nozzle, exploring different shapes of the inner body, and the computational fluid dynamic simulations of the supersonic nozzle is utilized to find out the best geometrical design. Utilizing a coupled pressure-velocity scheme with high order of discretization of the governing equation yielded to find the shockwave positions in different conditions. The turbulent behavior of the fluid in the shockwave zone is well discussed and the phase-change phenomena for the natural gas application are studied considering both water condensation and hydrocarbon condensation simultaneously. Different nozzle configuration elucidates the physical mechanisms of the supersonic flow inside the nozzle. Shockwave position, swirling velocity stability, and mass flow capacity are investigated. The lower the inner body radius, the less the change of shockwave position in the gas is found. Also, the higher stability of swirling velocity magnitude is found for the convergent-divergent inner body, which brings enhanced physical phase separation.