Analysis of nuclear thermal propulsion systems using computational fluid dynamics

Abstract

Computational fluid dynamics (CFD) analyses of nuclear rockets with relatively low chamber pressures were carried out to assess the merits of using such low pressures to take advantage of hydrogen dissociation and recombination. The computations, using a Navier‐Stokes code with chemical kinetics, describe the flow field in detail, including gas dynamics, thermodynamic and chemical properties, and provide global performance quantities such as specific impulse and thrust. Parametric studies were performed varying chamber temperature, chamber pressure and nozzle size. Chamber temperature was varied between 2700 K and 3600 K, and chamber pressure between 0.1 atm. and 10 atm. Performance advantages associated with lower chamber pressures are shown to occur at the higher chamber temperatures. Viscous losses are greater at lower chamber pressures and can be decreased in larger nozzles where the boundary layer is a smaller fraction of the flow field.