Core Length of Submerged Gas Jet Injected into Water and Mercury

Abstract

The core length of submerged super-sonic gas jet was measured in water or mercury bath as the basis of injection metallurgy. Two different methods were developed to measure the core length on the jet axis. One method was the kinetic pressure profile measurement and the another was the intensity measurement of the light which was emitted from the nozzle. The core lengths determined by both methods agreed well and increased with increasing stagnant pressure. Under the same stagnant pressure the core length decreased with increasing Mach number of the nozzle. Therefore, the contribution of static component of pressure to the core was larger than that of kinetic component. The core length in water was twice as large as that in mercury. An empirical equation to predict the jet core length was proposed and was compared with those reported. High pressure injection and the use of the nozzle with low Mach number and small diameter wakes the core of submerged jet long.