Second law analysis of compressible flow through a diffuser subjected to constant wall temperature

2010 ◽  
Vol 7 (1) ◽  
pp. 110
Author(s):  
Mohammad Hasan Arshad ◽  
Ramazan Kahraman ◽  
Ahmet Z. Sahin ◽  
Rached Ben Mansour
Keyword(s):  
Compressible Flow ◽  
Wall Temperature ◽  
Second Law ◽  
Constant Wall Temperature ◽  
Second Law Analysis ◽  
Flow Through

Discussion: “Second Law Analysis of Laminar Viscous Flow Through a Duct Subjected to Constant Wall Temperature” (Sahin, A. Z., 1998, ASME J. Heat Transfer, 120, pp. 76–83)

2007 ◽  
Vol 129 (9) ◽  
pp. 1302-1302 ◽  
Author(s):  
M. M. Awad
Keyword(s):  
Heat Transfer ◽  
Viscous Flow ◽  
Wall Temperature ◽  
Second Law ◽  
Constant Wall Temperature ◽  
Second Law Analysis ◽  
Flow Through

In the paper Sahin, A. Z., 1998, “Second Law Analysis of Laminar Viscous Flow Through a Duct Subjected to Constant Wall Temperature” ASME J. Heat Transfer, 120(1), pp. 76–83, there are many errors in equations, values, etc. The errors will be summarized below.

Second Law Analysis of Laminar Viscous Flow Through a Duct Subjected to Constant Wall Temperature

1998 ◽  
Vol 120 (1) ◽  
pp. 76-83 ◽  
Author(s):  
A. Z. S¸ahin
Keyword(s):  
Viscous Flow ◽  
Entropy Generation ◽  
Wall Temperature ◽  
Viscous Friction ◽  
Inlet Temperature ◽  
Total Heat Flux ◽  
Pumping Power ◽  
Constant Wall Temperature ◽  
Second Law Analysis ◽  
Flow Through

Entropy generation for a fully developed laminar viscous flow in a duct subjected to constant wall temperature is investigated analytically. The temperature dependence on the viscosity is taken into consideration in the analysis. The ratio of the pumping power to the total heat flux decreases considerably and the entropy generation increases along the duct length for viscous fluids. The variation of total exergy loss due to both the entropy generation and the pumping process is studied along the duct length as well as varying the fluid inlet temperature for fixed duct length. For low heat transfer conditions the entropy generation due to viscous friction becomes dominant and the dependence of viscosity with the temperature becomes essentially important to be considered in order to determine the entropy generation accurately.

Second law analysis of compressible flow through a diffuser subjected to constant heat flux at wall

2010 ◽  
Vol 51 (12) ◽  
pp. 2808-2815 ◽  
Author(s):  
Mohammad H. Arshad ◽  
Ramazan Kahraman ◽  
Ahmet Z. Sahin ◽  
Rached Ben-Mansour
Keyword(s):  
Heat Flux ◽  
Compressible Flow ◽  
Constant Heat Flux ◽  
Second Law ◽  
Constant Heat ◽  
Second Law Analysis ◽  
Flow Through

Second-Law Analysis of Heat Transfer in Swirling Flow Through a Cylindrical Duct

1987 ◽  
Vol 109 (2) ◽  
pp. 308-313 ◽  
Author(s):  
P. Mukherjee ◽  
G. Biswas ◽  
P. K. Nag
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Swirling Flow ◽  
Tangential Velocity ◽  
Merit Function ◽  
Second Law ◽  
Constant Wall Temperature ◽  
Boundary Layer Equations ◽  
Second Law Analysis ◽  
Cylindrical Duct

A second-law analysis is made on a swirling flow in a cylindrical duct with constant wall temperature. A purely tangential entry of the fluid is considered and a simplified model, consisting of a central air core enclosed by a potential, free vortex region and a boundary layer, is assumed. The approximate hydrodynamic boundary layer equations, and the continuity equation, are set up and solved numerically for the velocity gradients in the boundary layer. Similarly, the temperature gradients within the thermal boundary layer are obtained from the energy equation. The local Nusselt number and rate of entropy generation are calculated and used to evaluate the rate of heat transfer and loss of available energy, respectively. A merit function, defined as the ratio of exergy transferred to the sum of exergy transferred and exergy destroyed, is evaluated for various values of Reynolds number, based on the inlet tangential velocity, and conclusions are drawn about the influence of inlet swirl on irreversibility.

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