Raman measurements at the exit of a combustor sector

Abstract

Spontaneous Raman diagnostics are applied to the exit plane of an aircraft engine combustor sector fueled with both natural gas and liquid fuel (kerosene). Profiles of temperature and major species are obtained at the sector exit. The Raman mean temperature data agrees well with thermocouple measurements at identical operating conditions. The rms profiles show up to 12 and 16% fluctuations in temperature at the centerline of the burner with natural gas and kerosene, respectively. The mean profiles of major species show the expected trends. Up to 6% unburnt oxygen is measured at the centerline with natural gas. The corresponding value with liquid fuel is 8%. Profiles of Unburned hydrocarbons, carbon-monoxide, and hydrogen at the centerline indicate incomplete combustion at the measurement plane as also evidenced by the visible flame extending significantly beyond the sector exit. Profiles of normalized rms mole fractions of major species are also presented. Finally, the Raman system is applied to a room temperature cell at elevated pressures to extend the system to this regime. The Raman signals increase linearly with pressure as expected.