الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
This thesis is a comprehensive account of my experiences implementing the Lattice Boltzmann Method (LBM) for the purpose of simulating multiphase flows relevant to low prandtl numbers fluid applications at reduced gravity. There are other methodologies like finite difference method (FDM), finite volume method (FVM) and finite element method (FEM) that can simulate multiphase flow with reasonable success, but we choose to simulate with Lattice Boltzmann Method (LBM) because of its ability to capture multi-fluid physics and can be easily parallelized. This will save time in simulating larger problems. In this thesis we first give introduction to lattice Boltzmann method and it boundary conditions and it implementations, then we speak about nanofluids and its properties and how it affect base fluid in simulation and in practical applications, then we simulate natural convection for a low prandtl number fluid in square cavity at reduced gravity with Double single relaxation time (SRT) Thermal Lattice Boltzmann Method, The results obtained are a steady-state solution for some cases and oscillatory solution for some other, then we simulate natural convection for a low prandtl number fluid in square cavity at reduced gravity with a Double distribution function thermal lattice Boltzmann method with a two relaxation time (TRT) lattice Boltzmann method are used for solving the velocity field, while a single relaxation time (SRT) lattice Boltzmann method is used for solving the temperature field, The results obtained are a steady-state solution for some cases and oscillatory solution for some other. Then we study the simulations of natural convection in square cavity filled with low Prandtl numbers fluids with nanoparticles ((Al2O3- NaK) nanofluids) inside at reduced gravity with A Double distribution function thermal lattice Boltzmann method with a two relaxation time (TRT) lattice Boltzmann method are used for solving the velocity field, while a single relaxation time (SRT) lattice Boltzmann method is used for solving the temperature field. The simulations were done to study the effects of different Rayleigh numbers, the effects of different Prandtl numbers, different inclinations angles of the cavity and different nanoparticles volume fraction on the streamlines and isotherms of the fluid to enhance heat transfer rates. Our results suggest that the LBM algorithm is capable of simulating a wide range of flows and can capture flow physics with good accuracy and adding Al2O3 to NaK fluid will enhance heat transfer rates to this fluid.