Computational Study on the Flow Characteristics in a Film Cooled Dual-Bell Nozzle

A dual-bell nozzle comes under the classification of an altitude compensating nozzle. The absence of any moving parts makes the dual-bell nozzle a better substitute for the existing bell-shaped nozzles. In this study, a numerical simulation is carried out on a 2D axisymmetric dual-bell nozzle model to find the nozzle wall pressure distribution at different nozzle pressure ratio (NPR) which is validated with the experimental results from previous literature. The main flow is modeled as LO2/LH2 combustion mixture and secondary flow is modeled as GH2. Film cooling is introduced at the inflection point of the dual-bell nozzle to study the influence of the GH2 cooling film to the flow characteristics inside the nozzle. The influence of secondary coolant injection to the movement of separation location and film cooling effectiveness is studied by varying the coolant flow rate.