Experimental Study of a Rocket-Ramjet Nozzle Cluster

摘要

This research involved the investigation of pressure and flow fields in the base region of a clustered rocket-ramjet nozzle. Nozzle exit conditions simulating up to 75,000 feet and chamber-to-ambient pressure ratios of up to 200 were used. The clustered nozzles investigated simulated the flow for a pair of two-dimensional supersonic convergent-divergent rocket nozzles and a centered two-dimensional supersonic convergent-divergent ramjet nozzle. Six nozzle sets of various are ratios were examined. Schlieren photographs were used to assist in the flow field analysis. The results of this study indicate that the pressures in the nozzle base and the flow pattern downstream from the clustered nozzle exit are dependent on the ramjet nozzle inlet pressure. Additionally, a non-symmetrical oblique shock pattern formed as the clustered nozzle flow transitioned from the underexpanded regime to the overexpanded regime. It appears that the non-symmetrical shock pattern is a function of the chamber-to-ambient pressure ratio for the rocket nozzle and the area ratio for the rocket nozzle.