The influence of secondary flow structures in a turbocharger turbine housing in steady state and pulsating flow conditions

This paper presents a computational investigation into the effect of volute secondary flow structures on turbine inlet flow conditions. The steady state results show Dean type vortices exist early in the volute. As a result a substantial variation in absolute flow angle at the volute exit was observed. Pulsed flow simulations showed that the size and position of the secondary flow structures are time dependent. The resulting volute exit flow conditions were also found to be time dependent with the absolute flow angle at the volute exit varying with pulse pressure. This paper shows that that the secondary flow structures that exist in the volute as a result of cross sectional shape can have significant downstream effects on rotor performance.