Steady State Library for Liquid Rocket Engine Cycle Design

Abstract

The use of system modelling tools for design and analysis of liquid rocket engines is necessary during the pre-design activities; their exibility makes them a fundamental instrument along the entire design period from pre-design phase to parametric studies for ne tuning of the engine parameters. For this purpose these tools have to be reliable and fast, in order to perform iterative engine design loops and parametric studies in a reasonable time. Moreover, they should be able to perform o predictions and detailed analyses. The Steady State library presented within this paper enables to realize these purposes. Its object oriented structure ensures maximum exibility and allows for studying any liquid rocket engine thermodynamic cycle (open or closed). In this paper the tool is validated with the RL-10 engine and its capability will be demonstrated by designing several engine cycles. The entire library has been implemented within the existing analysis software EcosimPro, designed to model various kinds of dynamic systems. The standard propulsion library ESPSS can be used to study both stationary states and transients of a propulsion system. Unfortunately its use for steady state applications is not trivial because of the complexity of the transient models there implemented. Therefore, simpli ed pre-design and parametric studies are di cult and time-consuming. The library described in this paper has been designed speci cally for steady state purposes and can be considered as a completion of the ESPSS library, providing a helpful and fast tool for the pre-design phase and o analyses. To this aim, the available uid properties and combustion modelling functions of ESPSS have been implemented in an adequate form into the new libraries. Additionally, uid dynamic, combustion and heat transfer models have been developed to simulate the physical steady state behaviour of the main components of a propulsion system, as pipes, valves, turbines, pumps, ori ces, combustion chamber and nozzle. These components are suited for both launcher and spacecraft applications. The main components feature a ag that enables the user to switch from \design mode to the \o -design analysis mode to enhance the exibility of the library and perform di erent simulations with the same model. After the description of the main components of the Steady State library, their integration and validation will be presented through di erent examples of liquid rocket engine cycles design.