دانلود کتاب Open Source Mesh Generation and CFD Simulations for Francis Turbine [master's thesis]

Master’s Thesis in Sustainable Energy SystemsHydro power can be recognised as a relatively mature technology of all renewable energies.Efficiency around 90 % are commonly observed in Francis turbines. Since hydropower is relatively cheaper among other power sources, it is used as base power inenergy systems. Additionally hydro-power plants are often operated at off design conditions,which may lead to cavitation. Accordingly design improvements for improvingthe efficiency of the turbine at off design conditions are of great interest to designers.Computational fluid dynamics is used often for this analysis for predicting fluid flows asper modified design.In the field of Computational Fluid Dynamics, open source software have developeda significant role in past few years due to economical reasons and providing user accessto the source code. In many published works it has been successfully shown thatthe OpenFOAM solver produces comparable results to commercial codes. Most of thepublished work on OpenFOAM uses a mesh generated by a commercial software, mostcommonly on ICEM. As a step further in this thesis work, mesh has been generated onopen source software for a typical Francis turbine. The geometry used for this work hasbeen used from experimental rig for Francis turbine at Applied Mechanics Department.Further possibilities of parametrisation in terms of geometry and mesh distributionhave been explored. For diffuser complete parametrisation of geometry and mesh isachieved, for guide vane and Runner a structured mesh of acceptable quality has beenmade. To validate the mesh and mesh generation procedure simulations were carried outvarious operating conditions to analyse the flow. Two equation RANS models, standardk-e and it’s variant RNG k-e model have been used for turbulence modelling. Theefficiency of turbine did not vary much with choice of turbulence models. Overall it canbe concluded that Open Source Software for mesh generation and CFD simulations canbe successfully used for R&D in academia and industry