A STUDY ON THE FLOW PHYSICS OF ALTITUDE ADAPTIVE NOZZLES

Class of rocket nozzles which are capable of changing the effective flow area ratio with change in ambient pressure as it ascends through atmosphere are called altitude adaptive nozzles. Aerospike nozzles, expansion deflection nozzles, dual bell and double divergent nozzles are types of altitude adaptive nozzles. These nozzles are able to adapt to ambient conditions on account of the complex flow phenomena within. This paper discusses the topical problem of fluid flow physics in altitude adaptive nozzles such as annular aerospike, linear plug, expansion deflection and dual bell nozzles as the nozzle operates from low to high nozzle pressure ratios. The strategy to numerically model the flow within these nozzles is also discussed.