CARS (Coherent Antistokes Raman Scattering) Thermometry for Low and High Pressure Combustion Systems,

This paper discusses the theory and application of broadband CARS spectroscopy for ambient low and high pressure combustion thermometry. The accuracy of broadband CARS is assessed from 300-3500 Kelvin for pressures around 1 bar, and from 300-700 Kelvin for pressures from 1-20 bar. The use of CARS thermometry for both average and instantaneous measurements is discussed. Systematic accuracy strongly depends on the quality of the spectral model used in the CARS data analysis step, CARS spectral modelling methods are discussed. Instantaneous CARS accuracy is importantly influenced by noise arising in both the broadband dye laser and the multichannel detector. Both of these factors and their relative influences are assessed. Application of CARS thermometry is illustrated by application to both in-cylinder studies of an operating production i.c. petrol engine and to turbulent combustion in an oil-fired 30 kilowatt furnace.