In this paper

a numerical procedure to study the mixing flow in a circularly lobed nozzle is presented.The predictions are obtained by using SIMPLEC and complete pressure corrections algorithm to solve the incompressible Navier-Stokes equations.Turbulence is characterized by the standard k-ε eddy viscosity model.To fit the irregular boundaries of the flow field

curvilinear greatly nonorthogonal coordinates are used.The robustness of the computational procedure is enhanced by making use of nonstaggered grids. Results show that the thermal mixing efficiency of primary and secondary flow varies with the axial length of the mixer

and the streamwise vortex development.In the whole

the thermal mixing efficiency is not high

and the maximum value is 0.874.Good agreement between the numerical and experimental results is obtained for the axial velocity and temperature profiles in the outer section of the mixer

and the pressure coefficient on the wall of the mixer along the axial line.