Space vehicle propulsion systems: Environmental space hazards

The hazards that exist in geolunar space which may degrade, disrupt, or terminate the performance of space-based LOX/LH2 rocket engines are evaluated. Accordingly, a summary of the open literature pertaining to the geolunar space hazards is provided. Approximately 350 citations and about 200 documents and abstracts were reviewed; the documents selected give current and quantitative detail. The methodology was to categorize the various space hazards in relation to their importance in specified regions of geolunar space. Additionally, the effect of the various space hazards in relation to spacecraft and their systems were investigated. It was found that further investigation of the literature would be required to assess the effects of these hazards on propulsion systems per se; in particular, possible degrading effects on exterior nozzle structure, directional gimbals, and internal combustion chamber integrity and geometry

RANS study of very high Reynolds-number plane turbulent Couette flow

The objective of this study is to expound on the deliverables of a steady-state RANS (Reynolds Averaged Navier Stokes) simulation in one of the simplest flows, Couette flow, at a very high Reynolds number. To that end, a process to perform better grid sensitivity testing is introduced. Three two-equation turbulence models ( , , and ) are compared against each other as well as pitted against formal literature on the subject and core flow velocities, slopes, wall-bounded velocities, shear stresses and kinetic energies are analyzed. applied with enhanced wall functions is consistently found to be in better agreement with previous studies. Finally, plane turbulent Couette flow at 51,099, the range at which it has not been studied experimentally, numerically or analytically in former studies, is simulated. The results are found to be consistent with the trends asserted by literature and preliminary computations of this study