CASE WALL PRESSURES IN A MULTISTAGE AXIAL COMPRESSOR WITH TIP CLEARANCE VARIATION

Large cyclical pressure excursions from stator-averaged values are obs erved on the suction side of a rotor blade at the case wall in a multi stage compressor as the rotor moves relative to the stator, The pressu re changes correlate well with stator relative position, occur in the passage away from the blade, and are only slightly modified by tip cle arance changes, Close to the entry and exit of the tip gap, however, t he pressures remain stable. The pressures near the gap are only slight ly affected by stator proximity and primarily vary with tip gap height .