Laser Velocity Measurements in a Twin-Entry Vaneless Radial Turbocharger Turbine.

The flow field at the inlet and outlet of a twin-entry radial turbocharger turbine rotor has been measured using a laser-2-focus velocimeter (L2F) under steady flow condition, both at design and off design operating conditions. The test condition has been extended from full admission to a full range of partial admission condition from zero to maximum flow in each inlet of the twin-entry volute. By measuring the same point in the flow from another angle, it is possible to investigate the presence of the axial component of velocity at the rotor inlet, particularly under partial admission conditions. From these detailed measurements, it is possible to obtain new insights into the fluid dynamic processes of the turbine over varying operating conditions, particularly for partial admission conditions.