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.

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 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

EFFECTS OF THERMAL CREEP ON COOLING OF MICROFLOWS IN SHORT MICROCHANNELS WITH CONSTANT WALL TEMPERATURE

2012 ◽  
Vol 23 (11) ◽  
pp. 1250072 ◽  
Author(s):  
ALI AMIRI-JAGHARGH ◽  
HAMID NIAZMAND ◽  
METIN RENKSIZBULUT
Keyword(s):  
Wall Temperature ◽  
Temperature Jump ◽  
Control Volume ◽  
Velocity Slip ◽  
Temperature Gradients ◽  
Thermal Creep ◽  
Inlet Temperature ◽  
Constant Wall Temperature ◽  
Aspect Ratios ◽  
Wide Range

Fluid flow and heat transfer in the entrance region of rectangular microchannels of various aspect ratios are numerically investigated in the slip-flow regime with particular attention to thermal creep effects. Uniform inlet velocity and temperature profiles are prescribed in microchannels with constant wall temperature. An adiabatic section is also employed at the inlet of the channel in order to prevent unrealistically large axial temperature gradients due to the prescribed uniform inlet temperature as well as upstream diffusion associated with low Reynolds number flows. A control-volume technique is used to solve the Navier–Stokes and energy equations which are accompanied with appropriate velocity slip and temperature jump boundary conditions at the walls. Despite the constant wall temperature, axial and peripheral temperature gradients form in the gas layer adjacent to the wall due to temperature jump. The simultaneous effects of velocity slip, temperature jump and thermal creep on the flow and thermal patterns along with the key flow parameters are examined in detail for a wide range of cross-sectional aspect ratios, and Knudsen and Reynolds numbers. Present results indicate that thermal creep effects influence the flow field and the temperature distribution significantly in the early section of the channel.

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