Analysis of schemes of correction of dynamic characteristics of acoustic probes for measuring pressure pulsations in a gas turbine engine

Abstract

Gas pressure pulsations are one of the main parameters taken into account in gas turbine engine development. Therefore, special attention is paid to the accuracy of measuring pressure fluctuations. A high temperature of gas flow, sensor's size limitations in many cases do not allow it to be installed directly at the measurement point. There is a need to connect the sensor to the process using a waveguide channel (waveguide). It is known that resonant oscillations occur in the waveguide, leading to an additional dynamic error of the measuring channel. To improve the accuracy of measuring pressure fluctuations, corrective elements are used. A device consisting of a pressure pulsation sensor, a waveguide connected to the process, and a correction element is called a pressure pulsation probe in technical literature. In foreign and domestic literature there is a large amount of information on probes, but because of the variety of schemes of probe correction selecting those that would provide the required accuracy of measurement of pressure pulsations always poses a challenge. Therefore, taking into account the constant increase in the energy intensity of modern engines, and, accordingly, the increase in the temperature of working media, the authors analyzed the effectiveness of corrective elements on the basis of available patents, articles, and monographs. The article considers hardware and software schemes of correction of dynamic characteristics of acoustic probes based on corrective elements with distributed and lumped parameters. The advantages and disadvantages of the schemes are pointed out. Information on methods of calculating frequency characteristics of probes and their digital correction in the processing of experimental data is presented. The article will be of interest to developers of pressure pulsation probes and engineering and technical workers involved in GTE refinement.