Evaluation of Multi-Phase Equations of State for Liquid Rocket Engine Combustion Modeling (Conference Paper with Briefing Charts)
Conference Paper,01 May 2018,01 Feb 2019
AIR FORCE RESEARCH LAB EDWARDS AFB CA EDWARDS AFB United States
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Liquid rocket engines often operate in regimes where ideal gas equations of state are not applicable or have unacceptable levels of error. Mass flow rates are typically specified for the inlet boundary condition without an appropriate value of the density the incoming fluid velocity will be incorrect. The error in density between an ideal gas and the actual value can be more than an order of magnitude under the high pressure low temperature conditions found some kinds of liquid rocket engine injectors. The use of cubic equations of state will provide better estimates of the density but can lead to additional challenges when the mixture is sub-critical and inside the vapor dome. The present work looks at the development of a multi-fluid model using a cubic equation of state. At a computational cell level the mixture is assumed to be homogeneous. To achieve this Amagats law of partial volumes is applied to generate mixture averaged thermodynamic properties including density and enthalpy. Amagats law of partial volumes is applicable to mixtures of real gases unlike Daltons law of partial pressures which is only applicable to mixtures of ideal gases.
- Liquid Propellant Rocket Engines