LATTICE BOLTZMANN SIMULATION OF MAGNETHYDRODYNAMICS NATURAL CONVECTION FLOW FOR SALT WATER IN A HORIZONTAL CYLINDRICAL ANNULUS

Natural convection of an electrically conducting fluid under the different directions of magnetic field in a horizontal cylindrical annulus is numerically studied using lattice Boltzmann method (LBM). The inner and outer cylinders are maintained at uniform temperatures. Detailed numerical results of heat transfer rate, temperature and velocity fields have been presented for salt water with Pr=13.2, Ra=10^5 to 10^6 and Ha=0 to 100 for three directions of magnetic field. The computational results reveal that in horizontal cylindrical annulus the flow and heat transfer are suppressed more effectively by direction and intensity of magnetic field. It is also found that the flow oscillations can be suppressed effectively by imposing an external horizontal magnetic field.The average Nusselt number increases with rise in radius ratio but decreases with the Hartmann number. Furthermore, it can be observed that there is a good agreement between the present resultand those predicted by available benchmark solutions under the limiting conditions.