An Experimental Study of an Optimized Plain-Jet Airblast Atomizer

The relationship between the characteristics of a spray pattern that is generated by a simple external-mixing plain-jet atomizer, in pulse mode, and the control parameters of the injection system, has been investigated experimentally. The experimental conditions varied in the range of Re=1236 to 3540, We=65 to 595, and air/liquid velocity ratio from 15 to 110. The pulse duration varied between 3.4 and 18.5ms. It was found that, 1. the Sauter mean diameter is proportional to (Vf/V_a³)^0.5 over the entire range of operational conditions (within an error of ±7.5%), 2. a shorter pulse and a longer time interval between the pulses result in a smaller SMD, 3. the SMD may by decreased by some 25%, as compared to a continuous injection, when the pulse time duration reduces to 20% of the total cycle time, and 4. short time pulses and long interval between pulses, are always preferable to produce small droplets.