Flow Dynamics and Thrust Generation in De Laval Nozzles: A Study Using ANSYS Fluent

Kamal Gautam

Abstract: De Laval nozzle is a converging - diverging (CD) nozzle that can convert chemical energy with high pressure into kinetic energy with high velocity and low pressure. Manipulating variables such as area ratio and backpressure govern the flowing nature at the nozzle outlet to have either a supersonic flow or the existence of shock waves. This work reported a comprehensive flow simulation in a typical supersonic converging - diverging nozzle. This study is concerned with the study of the flow nature in the CD when the backpressure ratio was 10 kPa and 15 kPa for the given design of the nozzle. Mach number was supersonic for the pressure of 10 kPa. However, there was normal shock at the outlet with the Mach number reducing to 1 in case of 15 kPa backpressure. The pressure and density have been lowered, and velocity has been drastically increased at the outlet, producing greater thrust in the case of jet engines. The models were designed and analyzed using the ANSYS Fluent program. The results obtained from the ANSYS Fluent program were compared with the theoretical value calculated using isentropic flow equations for a nozzle.

Keywords: De Laval Nozzle, Mach Number, Shock Waves, Theoretical Validation, ANSYS FLUENT