An analytical investigation into the Nusselt number and entropy generation rate of film condensation on a horizontal plate

Abstract

This study investigates the heat transfer characteristics and entropy generation rate of a condensate film formed on a horizontal plate with suction at the wall. Applying the minimum mechanical energy principle, the dimensionless liquid film thickness along the plate is found to vary as a function of the Rayleigh number, the Jakob number, the Prandtl number and the suction parameter. The governing differential equation of the condensate thickness is solved numerically by using a finite-difference shooting method. Closed-form analytical expressions are derived for the Nusselt number and the dimensionless overall entropy generation number. When there is no suction at the wall, the results obtained from the analytical expression for the Nusselt number are found to be in good agreement with those presented in the literature.

Theoretical Analysis of Effects of Wall Suction on Entropy Generation Rate in Laminar Condensate Layer on Horizontal Tube

“…Substituting (16) and 17into (13)- (15), the dimensionless entropy generation numbers for the heat transfer and fluid friction irreversibilities are obtained, respectively, as follows:…”

“…Li and Yang [14] applied the entropy generation minimization method to optimize the heat transfer performance of a horizontal elliptical cylinder in a saturated vapor flow. In a recent study, Chang and Wang [15] investigated the heat transfer characteristics and entropy generation rate of a condensate film on a horizontal plate and found that the overall entropy generation rate induced by the heat transfer irreversibility effect is equivalent to the Nusselt number.…”

Entropy Generation of Forced Convection during Melting of Ice Slurry

“…In [ 30 ], the authors propose a method for the analysis of the entropy generation rate in the design of single-phase thermal processes, heat storage systems or various thermal cycles. The method proposed by Bejan [ 30 ] has been successfully used by other authors to perform a thermodynamic assessment of thermal processes during single-phase flows [ 31 , 32 ], multi-phase flows [ 33 , 34 , 35 , 36 , 37 , 38 ], heat exchange involving non-Newtonian fluids [ 32 , 39 , 40 ] and design of thermal systems and exchangers [ 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 ].…”

“…An analysis of the above papers suggests a very broad use of entropy generation rates for the assessment of diverse thermal [ 32 , 35 , 38 , 43 ], and flow processes, in which flow parameters [ 31 , 33 , 34 , 36 ] and geometrical parameters may be optimized [ 37 , 41 , 42 ]. The determined entropy generation rates refer to single processes [ 36 , 38 ], or to devices where processes involving various agents take place [ 41 , 42 , 43 , 44 ].…”

“…The determined entropy generation rates refer to single processes [ 36 , 38 ], or to devices where processes involving various agents take place [ 41 , 42 , 43 , 44 ]. Local or global values of the entropy generation rate may be determined analytically [ 32 , 33 , 34 , 35 , 38 , 39 , 42 , 44 , 46 ], or numerically [ 31 , 36 , 37 , 40 , 49 , 50 ].…”