Numerical and Experimental Investigation of the Flow and Performance Characteristics of Twin-Entry Radial Turbine Under Full and Partial Admission Conditions

In this paper, numerical and experimental investigation of the performance and internal flow field characteristics of the twin-entry radial inflow turbine under full and partial admission conditions are presented. The turbine is tested on a turbocharger test facility, which was developed for small and medium size turbochargers. The flow pattern in the volute and impeller of a twin-entry turbine is analyzed using fully three-dimensional viscous program. The computational performance results are compared with the experimental results, and good agreement is found. The flow field at the outlet of the turbine is investigated using a five-hole pressure probe. The tests are performed for both full and partial admission conditions numerically and experimentally. In the volute, results show that highest entropy gain factor belongs to the shroud side at partial admission conditions. In the inlet of rotor, flow at the partial admission condition is more prone toward shroud side than full admission. Meanwhile, entropy distribution contours corresponding to the exit plane are considered, which show entropy gain factor pattern do not have appreciable difference at full and partial admission conditions, and minimum entropy gain factor exists at shroud side near the suction surface and at hub side near the pressure surface.