A study on entropy generation on thin film flow over an unsteady stretching sheet under the influence of magnetic field, thermocapillarity, thermal radiation and internal heat generation/absorption

Abstract

Entropy generation is inherently affiliated with transport of thermal energy. However, not much attention has been paid to the study of entropy generation in liquid thin film flows. Hence, in this paper an analysis is carried out to study the entropy generation in a thin viscous fluid film on a stretching sheet embedded in a porous medium subject to a magnetic field and thermocapillarity force taking thermal radiation and internal heating/absorption into account. The numerical solution of the equations of momentum and energy governing the flow is obtained. Influence of various parameters emerged in the analysis on the velocity, temperature, surface drag, Nusselt number, entropy generation number and the Bejan number are graphically illustrated and discussed. Thermocapillarity number shows an enhancement of velocity at the free surface. Film thickness is found to increase with increasing thermocapillary force. Thinner films are noticed for stronger magnetic field strengths. It is found that in the absence of thermocapillary force, the effect of magnetic field on entropy generation number near the stretching surface is prominent. Thermocapillarity is seen to have a stronger effect on the entropy generation number near the stretching surface as well as at the free surface.

Entropy Generation in MHD Flow of Carbon Nanotubes in a Rotating Channel with Four Different Types of Molecular Liquids

“…The Bejan [1] formulated the entropy generation rate. Sarojamma et al [2] investigated the entropy generation in a thin film flow over a stretching sheet. Soomro et al [3] have as of late analyzed numerically the entropy generation in MHD water-based CNTs.…”

Entropy Generation in MHD Eyring–Powell Fluid Flow over an Unsteady Oscillatory Porous Stretching Surface under the Impact of Thermal Radiation and Heat Source/Sink

“…Along with an inclined permeable surface, Soomro et al [12] have recently examined, numerically, the entropy generation in MHD water-based CNTs. Mansour et al [13] have been examined the entropy generation rate in a laminar viscous flow in a circular flow, and have deliberated that the entropy generation rate is high near the wall than that of the center of the pipe. For the stagnation point, Rashidi et al [14] have been examined the flow in a porous medium through entropy generation.…”

Unsteady squeezing flow of magnetohydrodynamic carbon nanotube nanofluid in rotating channels with entropy generation and viscous dissipation

“…It is obvious from equation (28) that the Bejan number takes values from 0 to 1. Be = 0 leads to the case of irreversibility, due to magnetic field and fluid fraction dictate over the heat transfer irreversibility, while Be = 1 shows domination of irreversibility due to heat transfer on entropy generation.…”

“…The entropy generation was originally formulated by Bejan 27 over an unsteady stretching surface. Sarojamma et al 28 has examined the entropy generation on a thin film flow. Along with an inclined permeable surface, Soomro et al 29 recently examined numerically the entropy generation in magnetohydrodynamic (MHD) water-based CNTs.…”