The effect of reduced heat transfer in a micropolar fluid in natural convection

Abstract

This paper presents the numerical solution to the unsteady natural convection problem in micropolar fluid in the vicinity of a vertical plate, heat flux of which rises suddenly at a given moment. In order to solve this problem the method of finite differences was applied. The numerical results have been presented for a range of values of the dimensionless material properties and fluid Prandtl number. The analysis of the results shows that the intensity of the heat transfer in micropolar fluid is lower compared to the Newtonian fluid.

Unsteady natural convection in micropolar nanofluids

“…The value of microrotation parameter n from Eq. (18) is between 0 and 1 [7,8]. The value n = 0 corresponds to the case of the high density of liquid microparticles that prevents them from performing rotational movements.…”

“…The value n = 0 corresponds to the case of the high density of liquid microparticles that prevents them from performing rotational movements. The value n = 0.5 is indicative of weak concentrations and the value n = 1 is representative for turbulent boundary layer [7,8].…”

“…(24) such as microinertia density, rotational viscosity coefficient and spin gradient viscosity are related to the following equation [6][7][8]:…”

“…The amount of increase was only 5% compared to water without nanoparticles [3]. Due to miniaturisation of heat exchange devices, micropolar fluids as refrigerant or heating media are also analysed in [6][7][8]. A useful model of micropolar fluid is a model proposed by Eringen.…”

“…A useful model of micropolar fluid is a model proposed by Eringen. This model takes into account fluid microrotation [6][7][8].…”