TRANSONIC FAN TIP-FLOW FEATURES REVEALED BY HIGH FREQUENCY RESPONSE OVER-TIP PRESSURE MEASUREMENTS

摘要

Data from an array of high frequency response pressure transducers embedded in the casing wall over the tip of a transonic fan are reported. Phase-lock averaging of data from this array was successful in resolving an axial-tangential map of the static pressure rise in the rotor tip, as has been reported by other workers. Phase-lock ensemble RMS processing of the data is shown to be a useful technique that provides insight into the flow physics around the blade tip. Comparison with CFD results allows for more definite identification of features observed in the data. A complex flow field involving the casing wall boundary layer, the blade shock system and the over-tip leakage flow is observed. Differences between CFD data and measurements are explored by way of computational sensitivity studies. Results are reported for a range of throttle settings and speeds.