Computational study on the influence of variable diffusion coefficients on non-fourier transport in shear-rate-dependent fluid with solute particles

Abstract

Heat transfer in fluids occurs in numerous industrial processes. It is a fact that diffusion coefficients during heat transfer in fluids do not remain constant. Therefore, consideration of the constant diffusion coefficient is not a good approximation. In view of this, generalized modelling of heat and mass transfer in fluids of variable properties is done, and these generalized problems are solved by finite element method (FEM). After pre- and post-calculations, numerical runs are executed to observe the influence of variation in conductance on transport mechanisms in the fluid. The impact of other parameters is also studied. The outcomes are recorded in the form of graphs and numerical data. Ohmic dissipation results in an increase in the temperature of the fluid for variable and constant viscosity. The thermal relaxation time has shown significant effects on the flow and thickness of the thermal boundary layer region. The temperature of the fluid decreases with thermal relaxation time. The thermal conductance of the fluid varies with an increase in temperature. Once the temperature rises, the ability of the fluid to conduct heat is increased, due to which more heat from the heated surface diffuses into the fluid. Hence, heat flux decreases.The behavior of the variable viscosity of the fluid on the diffusion of momentum into the fluid is studied, and it is now known that the diffusion of wall momentum into the fluid is compromised because of a decrease in the viscosity, which is inversely proportional to the temperature. Hence, the diffusion of wall momentum into the fluid in the isothermal case is greater than that in the temperature-varying case.

Keywords

• Heat flux
• Generalized heat flux
• Variable properties
• FEM simulations
• Shear rate viscosity