Effect of orifice configuration on the penetration height in crossflow

In previous researches on jet in crossflow (JICF), which is applied for the liquid jet injection system of air-breathing propulsion systems or rocket engine system, more than 20 different correlations of jet penetration have been proposed. In these proposed correlations, the relationships between jet penetration and the various flow parameters (momentum flux ratio, Reynolds number, Weber number, viscosity ratio, etc.) were defined. But, most of these studies were carried out using the single orifice injector (SOI). In this study, in order to define the interference effects of liquid jet penetration in crossflow, the double orifice injector (DOI) is adopted. First, the jet penetration correlation of SOI according to the crossflow temperature controlled by the vitiated air heater is proposed. The jet penetration height for heated crossflow is lower than that for cold crossflow because of the increase of crossflow velocity despite the lower density. The jet penetration correlation of DOI is derived for variations of injector orifice spacing. In the case of the DOI, since the front liquid jet acts as a shield of the rear liquid jet, the jet penetration with DOI is higher than that with SOI. With the double orifice injector, the rear jet penetration height is increased as the nozzle spacing is decreased. And, The penetration height correlation for the rear liquid jet with DOI was developed. As the nozzle spacing increases, the jet penetration height decreases; therefore, an inverse relationship between nozzle spacing and jet penetration height is expected.