CFD Investigation for different nozzle jets

Abstract

Nozzle delivers thrust and gives momentum to the aerospace vehicle. Nozzle design is to be developed with respect to the application based on various factors under consideration during evolving of a system design. Specific impulse required is one of the major factors to define nozzle configuration with minimum variation in thrust delivered. As supersonic jet flow leaves the nozzle, it becomes a free shear layer, and action of turbulence dominates flow developments farther downstream. Therefore jet flow contains large interactions with surrounding medium. These combinations include turbulent mixing and compressibility effects such as isentropic expansion and shock. Numerical simulations are performed using commercially available software FLUENT to investigate and understand the performance of conical and scarfed nozzle. CFD Studies carried out for selecting a suitable mesh and selection of suitable turbulence model for computing nozzle jet flow field. Simulations were made using Spalart-Allmaras model and SST model. Based on the results, scarfed nozzle gives relatively low mach number compared to conical nozzle. The scarfed nozzle is preferred due to the missile configuration constraints.