Near-field spray characterization of a spill return atomizer using a PIV laser sheet

Abstract

Abstract The Combustion of liquid fuels is largely dependent on effective ways of atomization. The investigation of flow dynamics and atomization of alternative fuels is essential and supportive for combustion assessment. The current experimental investigation aims at providing a microscopic insight into the spray characteristics of the conventional (light diesel oil) fuel, a renewable fuel (waste cooking oil), and their blend together. A PIV laser measuring technique is used to provide detailed information on the fuel spray: droplets size, pattern, evaporation rate, instantaneous velocity, local cone angle, average axial velocity, penetration, and vorticity. The experiments cover four air to liquid ratios (ALR) of 0.8, 0.78, 0.65, and 0.57. A coaxial spill return atomizer is employed downwards as well as is surrounded by co-flowing air (kg/hr) of 48, 52.2, 55.8, and 60. The spray images are taken in an open atmosphere and the assessment of the fuel droplets velocity and size is obtained through PIV cross-correlation inside a glass room. The maximum evaporation rate is 48.1% for diesel fuel, 37% for waste cooking oil, and 44% for blended fuel at an ALR of 0.57. The application of co-flowing air (kg/hr) of 48 will reduce the local cone angle by 17%, 6%, and 4.3%. The interaction between waste cooking oil droplets with surrounding air is very difficult because of its high viscosity, density, lower evaporation rate, and larger droplets size than diesel fuel.