Numerical simulation of gas flows in a De-Laval micro nozzle

Venkata Vishnu Vardhan Gadepalli, Florida International University

Availability Unrestricted Thesis/Dissertation

Abstract

A numerical study has been conducted to understand the gas flows in a De-Laval micronozzles using 2D continuum axisymmetric model, which solves the governing equations by control volume method. The numerical model was validated with existing experimental data employing slip and no-slip boundary conditions at the wall. The numerical results showed good agreement with experimental data on exit thrust values except at low Reynolds number. Parametric studies included the effect of geometric scaling via scaling down of throat diameter for various throat Reynolds numbers and the effect of chemical propellants on the integrated performance of the nozzle. On the effect of geometric scaling, the nozzle throat diameter was scaled from 10 mm to 0.1 mm and the throat Reynolds number was varied from 5 to 100. A correlation was developed and presented to predict the specific Impulse for any given throat diameter and throat Reynolds number. To understand the effect of chemical propellants on nozzle performance, propellants like helium, nitrogen, argon and carbon dioxide were selected and simulations were conducted for throat diameter equal to 0.1, 1 and 10 mm respectively for Re_throat varying from 5 to 2000.