Laser diagnostics of atomization and combustion of kerosene in a model combustion chamber

Abstract

The experimental results are presented of implementation of a built-up laser-based diagnostic system at a test rig for investigations of the flame tube heads of aircraft gas turbine engines, both existing and being under development. At this test rig the processes of liquid fuel atomization and mixing with air by flame tube heads of model combustion chambers equipped with newly-developed atomizers, and of combustion of the fuel–air mixture formed in the flow have been studied. These studies enable development and optimization of advanced low-emission engines satisfying the established environmental requirements for the levels of polluting species in the exhaust gases. By using the particle shadow velocimetry technique with a pair of 10 μs delayed 5 ns laser pulses the transverse spatial distributions of average kerosene droplet dimensions, the axial components of their average velocity, and of the average volume flux of the fuel have been measured in the mixture flow axial cross-section. By employing coherent anti-Stokes Raman scattering with 10 ns pump laser pulses at 10 Hz repetition rate during combustion of the produced kerosene–air mixture the statistical characteristics of local ‘instantaneous’ gas temperature fluctuations in the flame, slow variations of these temperatures in time during the combustion process, and transverse distributions of average temperatures in the flame axial cross-section have been measured.