Digital Recording Device를 이용한 회전중인 블레이드 표면의 압력섭동 측정

Abstract

A new measurement system of wall pressure fluctuations on a rotating machinery, composed of digital recording device, was developed, evaluated. The small-sized digital recording device was attached on the rotating machinery, then was detached for data reduction. In order to obtain the system transfer function of the digital recording system, a dynamic calibration was performed utilizing the signal from a 1/8 inch B&K microphone as input. The time history of the unsteady pressure was then reconstructed from the output of the sensor by using this transfer function. The reconstructed pressure signals showed good agreement with the reference signal in both temporal, spectral sense. This sensor was then used to measure the wall pressure fluctuations on a rotating blade. An array of microphones were installed on the blade in the circumferential, radial directions. Various statistical moments were obtained from the measurement data set. Comparison of these quantities with the existing studies demonstrated satisfactory agreement. These tests give credence to the relevance, reliability of this device for applications in more complicated turbulent rotating machineries.