On the Use of Laser Rayleigh Scattering to Study the Aerothermochemistry of Recirculating Premixed Flames
The use of laser Rayleigh scattering, LRS, to study the thermochemistry of propane-air flames is shown to be accurate in the range of equivalence ratios 0.53 < ϕ< 0.70, making use of proper calibration procedures. The results have been analysed against thermocouple data and quantify the effect of flame luminosity on Rayleigh thermometry.
The measurements have been obtained in baffle-stabilised flames for Re= 150000 and the results are used to assess the effect of swirl, in the range 0 < S < 0.33, on the aerothermochemistry of strongly sheared flames. To achieve these objectives, a previously reported LRS/LDV system was conveniently optimised and the results show that swirl attenuates the rate of turbulent heat transfer across the reacting shear layer, although it does not alter the existence of a large flame zone characterised by non-gradient scalar fluxes. The results have been evaluated against those obtained with the combination of LDV with digitally compensated thermocouples, which are shown to be attenuated by up to 50% mainly due to the lack of spatial resolution.
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