INCREASING THE STABILITY OF COMBUSTION PROCESSES IN THE COMBUSTION CHAMBER OF GAS-TURBINE ENGINE THROUGH THE IMPROVEMENT OF THE AIRGAS CHANNEL

Abstract

A possibility of carrying out the numerical experiment using the up-to-date tools of computational hydrodynamics to predict pulsating combustion modes at the stage of engine development has been discussed. It will allow us to considerably reduce the expenditures required for the engine design and its development increasing simultaneously the operating efficiency of power systems. The purpose of this investigation is to increase the stability of combustion processes of gaseous fuel in the low-emission combustion chambers of gas turbine engines due to the gas-dynamic improvement of the air-gas channel. Theoretical studies showed that the gas-dynamic improvement of the air-gas channel in the low-emission combustion chambers of gas turbine engines allows us to enlarge the range of the stable operation of fuel-combustion system, to reduce pressure pulsations in the air-fuel mixture, and consequently reduce the vibrations of elements in the combustion chamber and in the engine on the whole. Theoretical investigations of the pulsation characteristics of the low emission combustion chamber with the preliminary mixing of air-fuel mixture for the gas turbine engine of 25 MW allowed us to establish that amplitude maximum pressure pulsations are observed in the paraxial recirculation zone, in the region of secondary air inlets; inside the flame tube in the region of the third and fourth cowlings; on inlet diffuser walls, in the output cross-section of flame tube before the turbine blades; on peripheral swirler blades, in the region of fuel outflow orifices and in swirler channels. The most efficient reduction of pulsations is observed in the primary combustion zone and the pulsations produced by the central vortex in the mixing zone closer to the chamber output are less efficient.