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

Document Type : Full Lenght Research Article


1 Malek-Ashtar University of Technology, Tehran, Iran.

2 Malek-Ashtar University of Technology, Tehran, Iran


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 ( C d) 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.


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