Specific features of pressure pulsation control in combustion chambers of land based gas turbine units

LLC SPC “Teplofizika”, developing low-emission combustion chambers with premixing of fuel for ground application gas turbine installations, investigates the problems associated with the occurrence of pressure pulsations in the combustion chambers, as well as with the methods of their registration and measurement. To date, there is no unified method for assessing and calculating the amplitude-frequency characteristics of these pulsations and their measurement in general. This article is based on many years of experience in measuring and recording pressure pulsations under the conditions of a test bench and operation. Methods for evaluating and accumulating measurement results are presented, criteria for determining the average frequency and amplitude of oscillations are developed, reproducible in the course of experiments and during full-scale measurements. To detect vibrating combustion, an additional criterion of coherence of vibrations is also used with the aid of the entropy coefficient. As a result of the computational and experimental study, we find that the pulsation pressure in the volume of the combustion chamber does not allow the use of probes for measuring pressure pulsations in the air volume of the combustion chamber to reliably prevent the occurrence of vibrating combustion during its operation.