Simulation of turbulent swirling flow in convergent nozzles

This work simulates the turbulent boundary layer of an incompressible viscous swirling flow through a conical chamber. To model the pressure gradient normal to the wall, the radial and tangential velocity components across the boundary layer have been calculated by both the integral and numerical methods. The numerical solution is accomplished by finite difference, based on the finite volume method. The results show that the radial and tangential boundary layer thicknesses depend on the velocity ratios, Reynolds number and nozzle angle. The peak of radial and tangential boundary layer thicknesses are located at z/L≈0.2z/L≈0.2 and z/L≈0.8z/L≈0.8 from the nozzle inlet, respectively. Due to the short length of the nozzle, the contribution of momentum change on pressure loss is more significant than that on the shear stress. Also, the pressure gradient normal to the wall had been considered more accurately than that of the previous attempts.