Inverse transfer function identification for high-frequency pressure probes using M-sequence pressure generators

Abstract

Accurate unsteady pressure measurement is important for the development and improvement of turbomachinery. The miniature pressure probe can adapt to the accurate measurement of pressure in a tight space under harsh working conditions, but the presence of the pressure transmission line makes the probe frequency response characteristics poor, and even causes the pressure signal to be distorted. In this paper, a novel Maximum-length sequence (M-sequence) pressure generator was developed, which generated pulsating pressure signals with wide frequency range and large amplitude pressure fluctuations at a fixed speed, and a time-domain parametric probe inverse transfer function identification method based on finite impulse response (FIR) adaptive filter using the generator was proposed. Four probes with different geometric parameters were fabricated. The probe inverse transfer function obtained by the FIR adaptive filter was compared with that obtained by the traditional non-parametric method to verify the accuracy of the identification method. The pressure at the pressure tap of the probes were reconstructed from the pressure measured by the probe and the inverse transfer function, which was in good agreement with the pressure measured by the reference sensor.