Injection Condition Effects of a Pintle Injector for Liquid Rocket Engines on Atomization Performances

Abstract

Key Words: Pintle Injector(핀틀 인젝터), Liquid Rocket Engine(액체로켓엔진), Spray(분무), Atomization(미립화) Abstract Effects of injection conditions on a pintle injector which is proper to recent liquid rocket engines requiring low cost, low weight, high efficiency and reusability were studied. The pintle injector with a typical moving pintle was used for atmo-spheric experiment using water and air. Injection pressures of water were considered 0.5 and 1.0 bar, 0.1 to 1.0 bar for injec-tion pressures of air and 0.2 to 1.0 mm for pintle opening distance. Sauter mean diameters (SMD) of spray was measured at 50 mm distance from a pintle tip and SMD was treated as a representative parameter in this study. As a result, because of shape characteristics of the pintle injector, there was a transient region between the pintle opening distances of 0.6 and 0.7 mm and this region affected to mass flow rates and SMDs. Also, Reynolds numbers for gas, Weber numbers and momentum ratios were adopted as major non-dimensional paramters and the momentum ratio has strong correlation with SMD.