Admission Effects on the Flow Behaviour of a Double Entry Turbocharger Turbine

Dual turbocharger turbine is fed by an unequal out-of-phase mass flow charge almost all the time which have significant effects on its performance parameters and flow phenomena which are not well known. Besides fully understanding the flow behavior in the radial turbine suffers from lack of detailed information about the secondary flows. This article studies the secondary flow structure within a dual entry turbine in different admission conditions. Results showed that with increasing the inequality of pressure ratio in the entries, performance of the turbine significantly decrease. From the results a profoundly disturbed flow in the interspace region was recognized. The pressure distribution of each limb shows some dependency between entries. To fully understand the flow physics, the 3D computational fluid dynamics (CFD) was implemented and compared with the experimental results of Copeland et al. (2010). The results are used to study the physical origin and the effect of nonuniform mass flow on secondary vortices. The generation and the development of the inflow, horseshoe and the corner vortex was investigated by evaluating contour plot of velocity distribution. Results demonstrated that the inflow vortex is due to the asymmetrical flow into the passage from the volute.