PhD Thesis - staffweb - University of Greenwich

PhD Thesis by John Ewer.A number of basic validation comparisons were also performed to check that the re-engineeredCFD system was consistent with the legacy CFD software. The actual simulation results and thedetailed set-up configurations, for these simulations, are not particularly relevant to the currentdiscussion and only a brief outline is given of the test cases and their respective results.The validation case "Diffusion controlled combustion" uses two parallel inlet jets with a jet offuel and a jet of oxidant into a 2D combustion chamber to test the simple combustion model.The Simple Chemical Reaction Scheme (SCRS) uses a much simplified chemical reactionequation which turns appropriate proportions of fuel and oxidant present within a cell into someproduct material with the consequent production of heat which is fed into the energy equation.Once again the re-engineered CFD system performed as expected and consistently whencompared to the legacy software.The validation case "Heat bar using multiple materials" uses simple heat transfer along a 2D barthat is constructed of two different materials. This heat transfer is caused by the imposition ofan elevated temperature boundary condition at one end of the bar whilst the other end ismaintained at some ambient temperature. The results for the temperature profile down the axisof the materials agree with the analytical results. This case reduces, essentially, to a 1Dimensional heat conduction problem. The results obtained were as expected for both the reengineeredand legacy software.The validation case "Heat bar using a triangular mesh" also uses a simple heat transfer along abar but in this case the bar is only constructed of a single material and uses an unstructured meshof triangular cells. The ends of the bar are maintained at different temperature and heat fluxboundary condition combinations and a steady state temperature profile is expected. Theunstructured correction terms are used to enhance the solution accuracy for these unstructuredmesh cells. The results from the prototype software give good agreement with the results fromthe legacy software and the analytic solution.The validation case "Heat bar using a user variable" uses a simple single material bar to checkthe user variable solver. In the normal case described above the heat variable is solved and5-87