Calculation of Enthalpy-Entropy Diagrams for Rocket Propellant Systems

Author: Slater, Mervin Otis

Year: 1948

Degree: Engineer's thesis

Advisor: Unknown, Unknown

Committee Member: Unknown, Unknown

Option: Aeronautics

DOI: 10.7907/J89N-WK27

Abstract

The purpose of this thesis is to present a method and the fundamental data necessary to construct enthalpy-entropy diagrams and from these diagrams to calculate theoretical performance of rocket motor propellants. The systems investigated using this method are:

(1) RFNA-Ammonia (1) (2) Ammonia (1)-Ozone (1) (3) Hydrogen (1) Ozone (1)

Enthalpy-entropy diagrams for these fuels were constructed for several different mixture ratios: over oxidized, stoichiometric, and under-oxidized. Performance was calculated assuming chamber pressures of 600 psia and 300 psia and exhaust pressures of 14.7 psia, 7.35 psia, and 0.147 psia. These diagrams facilitate the investigation of the effect of varying chamber pressure on chamber temperature and performance. They also facilitate investigation of varying expansion ratio, varying mixtures ratios, etc. They are especially useful in determining the performance of step rockets where exhaust conditions may vary from sea level to vacuum.

The results of the performance calculations indicate that performance found by using enthalpy-entropy diagrams checks closely with those determined by other methods. The performance of the last two systems is such as to indicate that a more thorough study of them should be made.

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