Ahmed Ketata^1,, Zied Driss¹

The radial turbine which is an important component of a turbocharger is used in automotive applications in order to enhance internal combustion engines performance. In the recent years, the radial turbine is commonly replaced instead of a mixed flow one. In fact, the mixed flow turbine yields to better aerodynamic performance at lower isentropic velocity ratio compared to the radial configuration. This present paper shows our numerical model under various steady conditions in purpose to understand the effect of the rotational speed on the turbine performance. Numerical simulations are conducted by solving the Reynolds averaged Navier Stokes equations using the CFX 17.0 package including a finite volume method for the discretization. To close these equations, the standard k-ε turbulence model is chosen. Our numerical model succeeds to predict the turbine performance and the swallowing capacity with an acceptable accuracy. Besides, the peak efficiency and the choking mass flow are computed for different operating conditions. Equally, the turbine reaction degree and power are given for each studied rotational speed. Then, the distribution of the total loss within the turbine is obtained numerically at different operating conditions.

CFD, turbulence, mixed-flow turbine, performance, mass flow, efficiency, loss