The development of efficient liquid rocket engines depends to some extent on our ability to develop realistic and reliable theoretical spray combustion models that can accurately predict its performance characteristics. To-date, several spray combustion models have been developed. But many of these make questionable assumptions with regard to the complex physical, chemical, and fluid-mechanical processes that occur in a reactive spray environment. One questionable assumption pertains to the burning/evaporation rate of droplets in a reactive spray. This proposal deals with the development of an innovative laser-based technique for the non-intrusive measurement of fuel droplet regression rates in reactive sprays. The measurement technique is based on the resonance elastic light scattering characteristics (resonance spectroscopy) of spherical particles. This research program will examine the feasibility of developing such a measurement technique and integrating it with the phase Doppler particle analyzer and the rainbow thermometer to yield an instrument that can be used for the simultaneous measurement of droplet size, velocity, temperature, and instantaneous regression rates of individual fuel droplets in complex reactive sprays.The successful completion of the Phase I and Phase II program will yield a novel diagnostic instrument that can be used to develop and validate theoretical spray combustion models, and to obtain a better understanding of the complex spray combustion process. Hence, such an instrument is bound to have significant commercialization potential.
