Flow Field Surveys at the Rotor Inlet of a Radial Inflow Turbine

Experiments were performed using a five-port cobra probe to survey the flow field at the rotor inlet of a 110-mm-dia turbocharger radial inflow turbine wheel. The turbine housing was modified to accommodate a probe insert to position the probe tip 4.1 mm above the rotor tip while preserving the internal contour of the production turbine housing. The cobra probe was traversed axially and circumferentially to determine the rotor inlet flow properties while the turbine was operated at design flow conditions with a reduced turbine inlet temperature. Measurements were made with the probe tip in the near-nulled position to determine the local values of total pressure, static pressure, velocity, and flow angle as functions of Z and θ. Results are presented showing the distribution of the housing total pressure loss coefficient, the rotor inlet mass flux, and the rotor inlet tangential velocity. In addition, values for rotor inlet mass average properties are given.