Title : Magnetohydrodynamic convective instability in binary nanofluids with thermodiffusion for Water (H2O) – Lithium Bromide (LiBr) absorption refrigeration system
Abstract:
The main objective of the present study is to investigate the effect of a vertical magnetic field on convective instability in binary nanofluids with thermodiffusion by performing stability theory and addition factor analysis. A physical system of Water-Lithium Bromide based binary nanofluid layer with a magnetic field is modeled by highly nonlinear partial differential equations. The expression for thermal Rayleigh number is derived analytically. The effect of nanoparticles on stability of the system is analyzed. The effect of nondimensional parameters on the Thermal Rayleigh number is presented graphically. It is found that an increase of the magnetic Chandrasekhar number is to decrease the size of convection cells. The size of convection cells is independent of volume fraction of nanoparticles, Lewis number, thermodiffusion of nanoparticles and solute. Moreover, the magnetic Chandrasekhar number and Lewis number have stabilizing effect on the system. The volume fraction of nanoparticles has destabilizing effect. Thermodiffusion of nanoparticles and solute have dual performance on the stability. They have stabilizing effect if δ4 < −1 and have destabilizing effect if δ4 > −1. Their performance is immaterial if δ4 = −1.
The present study has a great importance in many industrial applications such as absorption refrigeration and air conditioning, falling film absorption, freezing of foods, solar collectors, medical treatment, electro and electroless plating, etc. where the binary nanofluids are applicable as working fluids. The results of the study provide a good recommendation for selection of best pair of nanoparticle and solute in binary nanofluids.
Keywords: absorption refrigeration, binary nanofluid, convective instability, magnetic field, Thermodiffusion