Second law optimization of convective heat transfer through a duct with constant heat flux

Abstract

A second law analysis is carried out on convective heat transfer from a fluid flowing in a duct with constant heat flux. The entropy generated is expressed as a function of the initial temperature difference and the frictional pressure drop. Since the loss in available energy is directly proportional to the entropy generated, an optimum value of the initial temperature difference is found where the entropy generated is the minimum. A similar optimum is found for the ratio of heat transfer to pumping power. An optimum fluid velocity which corresponds to the minimum loss of available power is recommended.

Second Law Analysis in Convective Heat and Mass Transfer

“…The set of the dimensionless equations (9)(10)(11)(12)(13)(14)(15)(16)(17), show that the problem is governed by the dimensionless numbers of Pr, Sc, Gr T and N. The dimensionless thermal Grashof number, the buoyancy ratio and the inclination angle are the control parameters of the problem. On the other hand, if the temperature and the concentration are brought variables, the local entropy generation should be calculated in a dimensional form.…”

“…Nag and Kumar [14] studied second Law optimization for convective heat transfer through a duct with constant heat flux. In their study, they plotted the variation of entropy generation versus the temperature difference of the bulk flow and the surface using a duty parameter.…”

“…In their study, they plotted the variation of entropy generation versus the temperature difference of the bulk flow and the surface using a duty parameter. For this case [14], the product of Stanton number and the temperature difference between bulk and surface is constant due to the constant heat flux imposed on the surface. Shuja and al.…”

Second Law Analysis for Combined Convection in Non-Newtonian Fluids Over a Vertical Wedge Embedded in a Porous Medium

“…Sahin (1999) considered the variable viscosity effect on entropy generation rate in a circular pipe. Nag and Kumar (1989) presented second law optimization methods for duct flow processes. Mahmud and Fraser (2006) studied entropy generation in a circular pipe for power law non-Newtonian fluids.…”

Entropy Generation in Laminar Fluid Flow through a Circular Pipe

“…Application of the second law analysis for some steady flow devices can be found in references [12][13][14]. Nag and Kumar [15] studied the second law optimization for convective heat transfer through duct at constant heat flux boundary condition. Sahin [16] studied the second law analysis of viscous fluid in circular duct with isothermal boundary condition.…”