Study On Performance Analysis Model Of Rocket-Based-Combined-Cycle(RBCC) Engine

For it's excellent performance, Rocket-Based-Combined-Cycle (RBCC) should be the most competitive propulsion system of Hypersonic Flight Vehicle for martial and civil purpose. RBCC engine performance analysis model plays an important part in scheme selection and model design for Hypersonic Flight Vehicle, RBCC engine design and performance analysis. RBCC engine performance analysis model and corresponding software were both developed in this paper.Combustor performance analysis model was established based on quasi 1-D flow equation, considering mass injection, variance of cross section, skin friction, chemical reaction and so on. By-pass ratio can be acquired through the model. Compared with experimental results, it shows that the relative error is less than 10% for ejector performance prediction, less than 7% for scramjet.Fore-body performance analysis model was also realized, with the capability of determining mass captured, drag on ramp, parameters on inlet entrance. Operation state determining methods was created considering off design condition. Taking into account the boundary layer effect on flow structure, a correct formula was given. While comparing mass capture ratio with CFD result, the relative error is less than 2%.Response Surface Method (RSM) was adopted to predict aft-body performance. Screen tests were carried out to select the factors having important effect on the performance, resulting a reduction on Response Surface Equations' (RSEs) complexity. Six characteristic points was selected to rebuild aft-body pressure distribution by curve fitting, which have markedly improved the computing efficiency. Compared with CFD, the relative error is far behind 5%.RBCC Engine Performance Analysis Module (REPAM) was developed based on the aforementioned theoretical model. An application was carried out on a SSTO vehicle, Hyperion, the result is consistent with that from SCCREAM.