Exergy transfer characteristics of forced convective heat transfer through a duct with constant wall temperature

The exergy transfer characteristics of fluid flow and heat transfer inside a circular duct under fully developed laminar and turbulent forced convection are presented. Temperature is kept constant at the duct wall. The exergy transfer Nusselt number is put forward and the analytical expressions for exergy transfer Nusselt number are obtained as functions of heat transfer Nusselt number, Reynolds number, Prandtl number, etc. The variations of the local and mean convective exergy transfer coefficient, non-dimensional exergy flux, exergy transfer rate, etc. with operating parameters are presented graphically. By reference to a smooth duct and taking air as working fluid, a numerical analysis of the influence of the Reynolds number and non-dimensional cross-sectional position on exergy transfer characteristics has been conducted. The results show that the process parameters and configuration in the fluid flow and heat transfer inside a duct should be properly selected so that the forced convection process could have the best exergy utilization. In addition, the results corresponding to the exergy transfer and energy transfer are compared.

[1]  H. Oztop.  Effective parameters on second law analysis for semicircular ducts in laminar flow and constant wall heat flux , 2005 .

[2]  Noam Lior,et al.  The exergy fields in transport processes: Their calculation and use , 2006 .

[3]  A. Bejan.  Entropy generation minimization: The new thermodynamics of finite-size devices and finite-time processes , 1996 .

[4]  Yaşar Demirel,et al.  Linear-nonequilibrium thermodynamics theoryfor coupled heat and mass transport , 2001 .

[5]  Roydon Andrew Fraser,et al.  The second law analysis in fundamental convective heat transfer problems , 2003 .

[6]  Dusan P. Sekulic,et al.  Irreversibility phenomena associated with heat transfer and fluid friction in laminar flows through singly connected ducts , 1997 .

[7]  A. Bejan,et al.  Entropy Generation Through Heat and Fluid Flow , 1983 .

[8]  A. Bejan.  Fundamentals of exergy analysis, entropy generation minimization, and the generation of flow architecture , 2002 .

[9]  B. Hua,et al.  Exergy destruction due to mean flow and fluctuating motion in incompressible turbulent flows through a tube , 2003 .

[10]  Hsuan Chang,et al.  A new exergy method for process analysis and optimization , 2005 .

[11]  A. Sahin,et al.  The effect of variable viscosity on the entropy generation and pumping power in a laminar fluid flow through a duct subjected to constant heat flux , 1999 .

[12]  P. Nag,et al.  Thermodynamic optimization of convective heat transfer through a duct with constant wall temperature , 1987 .

[13]  A. Bejan.  Second law analysis in heat transfer , 1980 .

[14]  A. Bejan.  A Study of Entropy Generation in Fundamental Convective Heat Transfer , 1979 .

[15]  Ahmet Z. Sahin,et al.  Second Law Analysis of Laminar Viscous Flow Through a Duct Subjected to Constant Wall Temperature , 1998 .

[16]  J. Soma.  Exergy transfer: a new field of energy endeavor , 1985 .

[17]  Adrian Bejan,et al.  Models of power plants that generate minimum entropy while operating at maximum power , 1996 .

[18]  A. Khaliq.  Thermodynamic optimization of laminar viscous flow under convective heat-transfer through an isothermal walled duct , 2004 .

[19]  Q. H. Yin,et al.  A phenomenological equation of exergy transfer and its application , 2005 .

[20]  A. Sahin,et al.  Entropy generation in turbulent liquid flow through a smooth duct subjected to constant wall temperature , 2000 .

[21]  Mofid Gorji-Bandpy,et al.  Exergetic analysis of gas turbine plants , 2005 .

[22]  Ihsan Dagtekin,et al.  Entropy generation through hexagonal cross‐sectional duct for constant wall temperature in laminar flow , 2004 .

[23]  Naresh Kumar,et al.  Second law optimization of convective heat transfer through a duct with constant heat flux , 1989 .

[24]  A. Sahin,et al.  Thermodynamics of laminar viscous flow through a duct subjected to constant heat flux , 1996 .

[25]  Ahmet Z. Sahin,et al.  Entropy generation and pumping power in a turbulent fluid flow through a smooth pipe subjected to constant heat flux , 2002 .

[26]  Noam Lior,et al.  The Component Equations of Energy and Exergy , 1992 .

[27]  Qiao Chun.  DESCRIPTION OF EXERGY TRANSFER IN THE TWO DIMENSIONAL THERMAL CONDUCTION PROCESS , 2003 .

[28]  Adrian Bejan,et al.  The thermodynamic design of heat and mass transfer processes and devices , 1987 .