SYSTEM ANALYSIS OF A STAGED COMBUSTION ROCKET ENGINE
Typ
Examensarbete för masterexamen
Master Thesis
Master Thesis
Program
Applied mechanics (MPAME), MSc
Publicerad
2013
Författare
Capitao Patrao, Alexandre
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
The ability to accurately simulate how liquid rocket engines react at the system level with changing component parameters is important for a company like GKN Aerospace. Information from system performance models and trade-off studies can be used for focusing product development, evaluating the competition, and as a decision support tool when negotiating with business partners and customers. The project has three distinct deliverables; the first one is a functional description of a staged combustion rocket engine, for which the Space Shuttle Main Engine (SSME) has been chosen. The second deliverable is a steady state performance model capable of simulating and producing realistic results, and the third deliverable is a trade-off study which analyses how the system performance changes with changing component parameters. The first deliverable of the project was carried out as a literature study. The second and third parts used the information gathered in the literature study to build a performance model with a software called EcosimPro, which is a tool used to simulate transient systems described with differential-algebraic equations (DAE), ordinary differential equations (ODE) or discrete events. The project used the European Space Propulsion System Simulation (ESPSS) libraries to build the performance models. The project used a bottom-up approach for the system modelling, beginning with separate simulations of all components, and then synthesising increasingly larger engine models, until reaching a system model of the SSME. Due to lack of time and various modelling challenges, the project did not result in a functioning performance model of the complete SSME. A performance model was built, but the simulations never reached a satisfactory operating point. Results were obtained for a pseudo-cycle which contains most of the major components, in particular the high pressure turbomachinery, preburners, and thrust chamber. The results showed good coherence (maximum 6 % error) with reference data for the preburner and thrust chamber components. Unfortunately, the modelled turbine components did not deliver enough power, resulting in a maximum error of 20 %. The mixed quality of the results suggests that more effort has to be invested into the modelling of the SSME turbines and understanding how to properly achieve startup on a rocket engine as complex as the SSME. The current ESPSS libraries are too complex for design and trade-off studies, and the required startup makes modelling increasingly challenging and time-consuming. There is a new library under development, named STEADY, which will be more appropriate for the type of studies this project aimed for. Key words: Staged combustion rocket engine, system modelling, EcosimPro, ESPSS.
Beskrivning
Ämne/nyckelord
Farkostteknik , Rymd- och flygteknik , Strömningsmekanik , Mekanisk energiteknik , Vehicle Engineering , Aerospace Engineering , Fluid mechanics , Mechanical energy engineering