A Study on Flow Measurement Scheme by Stepwise Rotation of Total-Pressure Tube in Flow with Steep Velocity and Pressure Gradients

Abstract

Errors in measurements of shear flow by 3-hole yawmeters are usually attributed to the disturbance of flow by the probe head and the finite distance between pressure taps. For this reason, measurements of such flow as observed at the exit of a blade row become difficult in the steep velocity and pressure gradients. This paper deals with a study of a measurement scheme by stepwise rotation of a total-pressure tube which can reduce the above errors, and makes clear the high accuracy of the measured results experimentally, comparing them with the results by an ordinary 3-hole yawmeter. Exit flows from a stationary nozzle and rotating passages are used for the test. The suitable angle for stepwise rotation of the total-pressure tube and the preferable configuration of the probe head are also investigated.