Numerical simulation of turbulent compressible flows in a C-D nozzle with different divergence angles

Compressible gas flow inside a convergent-divergent nozzle and its exhaust plume at different nozzle pressure ratios (npr) have been numerically studied with several turbulence models. the numerical results reveal that, the sst k–ω model give the best results compared with other models in time and accuracy. the effect of changes in value of divergence half-angle (ε) on the nozzle performance, thrust coefficient ( cf ) and discharge coefficient ( cd ) has been investigated numerically. the predicted results show that for a given divergence angle, the thrust coefficient ( cf ) increases by increasing nozzle pressure ratio. also, for a given nozzle pressure ratio, the thrust coefficient increases as the nozzle divergence angle decreases. when the cd nozzle is chocking, the value of discharge coefficient is independent of nozzle pressure ratio and also for a given nozzle pressure ratio, the discharge coefficient increases as the divergence nozzle angle (ε ) increases.