Numerical Study of a Vanned Mixed Flow Turbine Operating in Various Steady Flow Conditions

In purpose to improve engines emissions and its output torques, automotive manufacturers use boosting systems such turbochargers in which the turbine presents a critical component. This paper presents the numerical model for steady simulations of a mixed flow turbine. Simulations are done by solving Navier-Stokes equations using a finite volume method for the discretization. The swallowing capacity and the efficiency are plotted against the rotational speed of the turbine shaft in order to know its effect on the turbine operating capacity. Furthermore, reaction degree and rothalpy are computed for each operating condition to characterize the contribution of the rotor to the output work in the full turbine stage. To analysis the flow behavior at off-design conditions, distributions of the velocity and the pressure at different operating conditions are numerically obtained. A good agreement is found between computed results and test data confirming the validity of our numerical method.