Two-Phase Choked Flows of Gas and Particle in a Convergent-Divergent Nozzle

Particle-gas two-phase flows show significantly different behaviors compared to single gas flow through convergent-divergent nozzles. Non-equilibrium effects, thermal and velocity lags lead to the inefficiency of nozzle performance. In the present studies, theoretical analysis and numerical simulations were carried out to study particle-gas flows through a C-D nozzle. Homogeneous equilibrium model that no lag in velocity and temperature happen between particles and gas phase was considered to derive choked mass flow rate and sound speed of multiphase flows. Two-phase flows are regarded as isentropic flows that isentropic relations can be used for homogeneous equilibrium model. Discrete phase model (DPM) where interaction with continuous phase and two-way turbulence coupling model were considered was used to simulate particle-gas flows. Particle mass loading (PML) was varied to investigate its effect on choking phenomena for particle-gas flows. Particle volume fraction, specific heat ratio, velocity slip ratio and sound speed of mixture flows were theoretically calculated by homogeneous equilibrium model and compared with numerical results.