Instantaneous temperature measurement of supersonic combustion using Coherent Anti-Stokes Raman Scattering

A single-laser-shot N2 Q-branch Coherent Anti-Stokes Raman Scattering (CARS) is used to measure the instantaneous temperature of supersonic combustion in kerosene/air flame with Mach 2.6. The Unstable-resonator spatially enhanced detection (USED) phase matching is used to reduce turbulence effects and to improve the CARS signal intensity. An USED CARS measurement system, which has a high spatial solution of similar to 100 mu m in diameter, and a CARS spectrum calculating and fitting program CARSCF are developed. The CARS signal in supersonic combustion is measured and then used to calculate temperature, the results show that, during kerosene/Air ignited in Mach 2.6, the CARS signal first rise rapidly then fall sharply and finally rise slowly, while the temperature increase sharply and then decrease slowly and the average temperature is 1970 +/- 144K with 6.5% of repeatability.