FLOW ANALYSIS OF A RADIAL-INFLOW VARIABLE GEOMETRY TURBINE STATOR VANE RING USING PARTICLE IMAGE VELOCIMETRY

摘要

An optimization at the lower off-design mass-flow range of the radial-inflow variable geometry turbine is required for future turbine applications. One of these applications is using this type of turbine as the throttling apparatus for a spark ignition engine to recover energy which is wasted by the conventional throttle. A wide operating mass-flow range with significant turbine efficiency is needed for these applications. The stator-to-rotor interaction is optimized of a standard radial-inflow turbine by changing the variable-vane-angle stator vane ring geometry. The flow at the conventional and a new design stator vane ring is analyzed using particle image velocimetry (PIV) with the intention of using the results to substantiate the increase of performance of the new turbine with new designed stator vane ring and for the admittance of computational fluid dynamic simulations. A PIV experimental setup is built to visualize the jet flow between and directly downstream the stator vanes. Two-dimensional steady-state jet-flow characteristics are mapped at several stator vane positions. Two series of fixed positioned stator vane rings are fabricated by rapid prototyping which represent the original and new variable-vane-angle stators. The flow characteristics of both series of vane rings are compared.