Energy transfer in mixed convection unsteady magnetohydrodynamic (MHD) flow of an incompressible nanofluid inside a channel filled with a saturated porous medium is investigated. The walls of the channel are kept at constant temperature, and uniform magnetic field is applied perpendicular to the direction of the flow. Three different flow situations are discussed on the basis of physical boundary conditions. The problem is first written in terms of partial differential equations (PDEs), then reduces to ordinary differential equations (ODEs) by using a perturbation technique and solved for solutions of velocity and temperature. Four different shapes of nanoparticles inside ethylene glycol (C2H6O2) and water (H2O)‐based nanofluids are used in equal volume fraction. The solutions of velocity and temperature are plotted graphically, and the physical behavior of the problem is discussed for different flow parameters. It is evaluated from this problem that viscosity and thermal conductivity are the dominant parameters responsible for different consequences of motion and temperature of nanofluids. Due to greater viscosity and thermal conductivity, C2H6O2‐based nanofluid is regarded as better convectional base fluid assimilated to H2O.
Part of the book: Nanofluid Heat and Mass Transfer in Engineering Problems
Heat and mass transfer analysis in magnetite molybdenum disulphide nanofluid of grade two is studied. MoS2 powder with each particle of nanosize is dissolved in engine oil chosen as base fluid. A generalized form of grade-two model is considered with fractional order derivatives of Caputo and Fabrizio. The fluid over vertically oscillating plate is subjected to isothermal temperate and species concentration. The problem is modeled in terms of partial differential equations with sufficient initial conditions and boundary conditions. Fractional form of Laplace transform is used and exact solutions in closed form are determined for velocity field, temperature and concentration distributions. These solutions are then plotted for embedded parameters and discussed. Results for the physical quantities of interest (skin friction coefficient, Nusselt number and Sherwood number) are computed in tables. Results obtained in this work are compared with some published results from the open literature.
Part of the book: Microfluidics and Nanofluidics