Experimental investigation of a pressure swirl atomizer spry

The fuel injector has an important role in the process for an efficient combustion because it increases the specific surface area of the fuel and it allows one to reach high rates of mixing and evaporation. This paper has focused on the behavior of kerosene Jet A-1 spray produced by commercial pressure swirl atomizers in terms of mean diameter distributions, velocity component profiles, and cone angle variations over time. The analysis has been carried out experimentally with the aid of a phase-Doppler anemometer system, which provides drop sizes and velocities. The fluctuating behavior of the spray has been analyzed also with a fast imaging technique by means of a high-speed charge-coupled device camera. The instantaneous spray cone angle, estimated with a digital image analysis, has shown that the average cone angle roughly equals the one calculated with phase-Doppler anemometer data, and that it is different from its nominal value. A preliminary investigation into the frequency domain has shown two oscillation modes at low frequency around 100 Hz and at high frequency around 1800 Hz. This issue is a key result because spray oscillations affect the flame stability and the resulting combustion, efficiency because a change in the local air/fuel mixture ratio is induced.