Measurement of Fuel Spray Interactions

Quantitative measurement of spray patterns is of fundamental importance in the development of efficient and practical aerospace propulsion and power systems. At present, there is considerable interest in obtaining measurements of fuel and air motions in both fuel droplet and solid particle combustors since the velocity of the fuel relative to the gas strongly influences the local oxygen supply, the removal of combustion products, and hence the fuel burning rate and pollution formation. However, our present understanding of the details of the interaction between the fluid dynamic and chemical processes does not permit us to predict the effects of specific changes in operating conditions. This lack of understanding is primarily due to the complex nature of fuel spray combustion which involves simultaneous heat, mass, and momentum transfer, and chemical reactions which are all influenced by fuel type, ambient gas composition, temperature and pressure,and the fuel droplet or particle size distribution. To alleviate these problems it is proposed to develop new optical diagnostic systems which combine global laser light sheet droplet flow visualization with quantitative fluorescence and Doppler measurements of fuel spray density and velocity.