Analysis of Ambient Gas Entrainment Processes in Intermittent Gas Jets by LIFA Technique

Time-resolved and local ambient gas entrainment processes in intermittent gas jets with a range of injection conditions were evaluated by a LIFA (Laser-Induced Fluorescence of Ambient gas) technique. The gas injection conditions tested were: mean discharge velocity, um; mean discharge turbulence intensity, u′_m; kinematic viscosity of the gas jet, ν; specific gravity of the gas jet, ρ_j; and of the ambient gas, ρ_a. Experimental results showed that the entrainment of jets are enhanced with higher eddy kinematic viscosity, ν_t, measured by a hot wire anemometer. In conclusion, the mean jet concentration was approximated with only one parameter, (ρ_j/ρ_a)D²/[(ν+ν_t)Δ_t].