One-Dimensional Gas Dynamics in Nitrous Oxide Rocket Systems

Abstract

Liquid and hybrid rocket systems that utilize high-pressure liquid nitrous oxide (N2O) are susceptible to accidental decompression. These very rare events have catastrophic potential and have led to loss of human life in the past. Traditional thinking considers those events as driven by catalytic chemical decomposition reactions; the objective of this work is to examine such events in the light of BLEVE (Boiling Liquid Expanding Vapor Explosion). The static picture of BLEVE will be described here as a metastable phase transition between liquid and vapor phases, using Clausius II thermodynamics (statics) to describe the retrograde behavior of the fluid. The dynamics of a hypothetical BLEVE process inside nitrous rocket-propellant tanks will also be examined using 1-D gas dynamics, and specifically by considering three ’canonical’ flows and their combinations: Area variation, Fanno friction flow, and Rayleigh heat addition.

This thesis will provide an outline of Clausius II and how it was applied to various flows through the use of a 1D model coded in Python [5]. The results obtained from this coded model will be plotted and explained in order to either validate or give further work ideas to the theory initially provided.