Lattice Boltzmann simulation of magneto-hydrodynamic double-diffusive natural convection in an enclosure with internal heat and solute source using nanofluids

Abstract

Magneto-hydrodynamic double-diffusive natural convection in a cavity is numerically investigated in the present work. Al 2 O 3 , Cu, and Ag based nanofluids in a square cavity with a thermal and solute source in the center, and uniform magnetic field are considered. The Patel model is employed to estimate the thermal conductivity of applied nanofluids, and the numerical calculation is based on the implementation of the lattice Boltzmann method and utilizing the standard D 2 Q 9 model to study the heat transfer, and also species concentration. A parametric study is carried out to observe the influence of the type, the volume fraction of nanoparticle ( = 0 − 5% ), Rayleigh ( Ra = 10 4 − 10 5 − 10 6 ) , Lewis (0.1 − 2 − 10) , and Hartmann number (10 − 20 − 100) on average Nusselt and Sherwood numbers, flow fields, temperature, and concentration distribution. The results show that an augment in nanoparticle volume fraction and Rayleigh number increased the average Nusselt and Sherwood numbers. Lewis number showed a significant impact on mass transfer rate. However, it did not affect the heat transfer rate remarkably. Applying a magnetic field caused a reduction in flow circulation which resulted in a decline in heat and mass transfer. A comparison of the simulation outcome with the available data shows that the generated code perfectly captures the fluid flow behavior and heat transfer process as a function of the affecting parameters. KeywordsMHD double-diffusive natural convection • Square enclosure • Nanofluids • Lattice Boltzmann method List of symbols Ar Aspect ratio B The magnitude of the magnetic field, T c Lattice speed, m∕s c i Discrete particle speed, m∕s c s Sound velocity, m∕s C Concentration C p Specific heat, Jkg −1 K D Mass diffusivity, m 2 ∕s f , g, h Discrete distribution function F External force

Lattice Boltzmann simulation on thermal management of electronic components with nonuniform temperature based on nanofluids

“…Results showed that the longer baffle is always more effective with proper positioning. Ghasemi et al 41 and Afzalabadi et al 42 all investigated the influence of magnetic field on the natural convection of nanofluids by lattice Boltzmann method, and the results presented that magnetic field has a negative influence on thermal performance. Mliki et al 43 simulated the influence of Ha on the natural convection of nanofluids in a linearly/sinusoidally heated cavity by lattice Boltzmann method, and it was indicated that thermal performance decreases with Ha .…”