System to Measure the Pressure Distribution on Fan Aerofoil Surfaces During Flutter Conditions

Abstract

In order to assist in the understanding of high speed flutter, a series of tests has been conducted on a research fan in which the blade surface pressures have been measured by means of miniature silicon diaphragm pressure transducers embedded in selected fan blades. Prior to this investigation a program of rig tests was conducted to examine the effects of centrifugal force and vibration on the transducer performance and a transducer mounting technique was developed to minimize blade induced stress in the transducer. Instantaneous measurements of the tip stagger angles of the pressure instrumented fan blades have enabled a cross correlation to be performed on the blade surface pressure data and the blade tip angles. Some typical test results are shown.