Combustor fluctuating pressure measurements in engine and in a component test facility — a preliminary comparison

Abstract

As part of a program to investigate combustor noise, simultaneous measurements were made with a YF-102 engine of combustor internal fluctuating pressure and farfield noise. As the dependence of farfield noise on engine internal measurement becomes understood, an important question becomes the connection between combustor internal measurements obtained in an engine and those obtained in a component test facility. To explore this question, a YF-102 combustor, instrumented identically with that of the engine tests, was operated in a component test facility over a range of conditions encompassing engine operation, and the fluctuating internal measurements were repeated. A comparison of the directly measured spectra at corresponding locations in the two tests shows significant differences. However, the results of two-point signal analyses within each combustor such as coherence function, transfer function, and phase relationships are similar for both tests. This indicates that the internal dynamics of the combustor as an acoustic source are preserved in a component test facility.