Ultra high speed investigation of gaseous jet injected by a single-hole injector and proposing of an analytical method for pressure loss prediction during transient injection

The objective of this study is to investigate the characteristics of a transient gaseous jet produced by a single-hole injector nozzle. High speed schlieren is used to image the jet development process and evaluate time-dependent characteristics of the jet. Both near and far fields have been investigated through two distinct optical configurations. Helium gas was injected at nozzle pressure ratios of 2, 3, 4 and 5 and the effects of nozzle pressure ratio on the jet axial and radial penetrations and tip velocity were investigated. An analytical model is proposed to calculate the pressure drop during transient injection using shock tube theory. Modification of existing predictions with this pressure drop model offered significantly better agreement with the experimental data.