Entropy Generation in Thermally Developing Laminar Forced Convection Through a Slit Microchannel

2010 ◽  
Author(s):  
Arman Sadeghi ◽  
Mostafa Baghani ◽  
Mohammad Hassan Saidi
Keyword(s):  
Forced Convection ◽  
Entropy Generation ◽  
Energy Equation ◽  
Integral Transform ◽  
Axial Coordinate ◽  
Entropy Generation Number ◽  
Group Parameter ◽  
Laminar Forced Convection ◽  
Thermal Entrance ◽  
Increasing Function

The issue of entropy generation in laminar forced convection of a Newtonian fluid through a slit microchannel is analytically investigated by taking the viscous dissipation effect, the slip velocity and the temperature jump at the wall into account. Flow is considered to be hydrodynamically fully developed but thermally developing. The energy equation is solved by means of integral transform. The results demonstrate that to increase Knudsen number is to decrease entropy generation, while the effect of increasing values of Brinkman number and the group parameter is to increase entropy generation. Also it is disclosed that in the thermal entrance region the average entropy generation number over the cross section of channel is an increasing function of axial coordinate.

scholarly journals Numerical investigation of entropy generation in laminar forced convection flow over inclined backward and forward facing steps in a duct under bleeding condition

2014 ◽  
Vol 18 (2) ◽  
pp. 479-492 ◽  
Author(s):  
Meysam Atashafrooz ◽  
Nassab Gandjalikhan ◽  
Babak Ansari
Keyword(s):  
Numerical Investigation ◽  
Forced Convection ◽  
Entropy Generation ◽  
Fluid Dynamic ◽  
Numerical Results ◽  
Convection Flow ◽  
Bejan Number ◽  
Entropy Generation Number ◽  
Forced Convection Flow ◽  
Laminar Forced Convection

A numerical investigation of entropy generation in laminar forced convection of gas flow over a recess including two inclined backward and forward facing steps in a horizontal duct under bleeding condition is presented. For calculation of entropy generation from the second law of thermodynamics in a forced convection flow, the velocity and temperature distributions are primary needed. For this purpose, the two-dimensional Cartesian coordinate system is used to solve the governing equations which are conservations of mass, momentum and energy. These equations are solved numerically using the computational fluid dynamic techniques to obtain the temperature and velocity fields, while the blocked region method is employed to simulate the inclined surface. Discretized forms of these equations are obtained by the finite volume method and solved using the SIMPLE algorithm. The numerical results are presented graphically and the effects of bleeding coefficient and recess length as the main parameters on the distributions of entropy generation number and Bejan number are investigated. Also, the effect of Reynolds number and bleeding coefficient on total entropy generation which shows the amount of flow irreversibilities is presented for two recess length. The use of present results in the design process of such thermal system would help the system attain the high performance during exploitation. Comparison of numerical results with the available data published in open literature shows a good consistency.

Second Law Analysis for Extended Graetz Problem Including Viscous Dissipation in Microtubes

2010 ◽  
Author(s):  
Arman Sadeghi ◽  
Mostafa Baghani ◽  
Mohammad Hassan Saidi
Keyword(s):  
Entropy Generation ◽  
Integral Transform ◽  
Entropy Generation Rate ◽  
Dimensionless Temperature ◽  
Brinkman Number ◽  
Axial Coordinate ◽  
Entropy Generation Number ◽  
Nusselt Numbers ◽  
Heating Effects ◽  
Second Law Analysis

The entropy generation rate has become a useful tool for evaluating the intrinsic irreversibilities associated with a given process or device. This work presents an analytical solution for entropy generation in hydrodynamically fully developed thermally developing laminar flow in a microtube. The rarefaction effects as well as viscous heating effects are taken into consideration, but axial conduction is neglected. Using fully developed velocity profile, the energy equation is solved by means of integral transform. The solution is validated by comparing the local Nusselt numbers against existing literature data. From the results it is realized that the entropy generation decreases as Knudsen number increases, while the effect of increasing values of Brinkman number and the ratio of Brinkman number to dimensionless temperature difference is to increase entropy generation. The average entropy generation number over the cross section of channel increases with increasing values of axial coordinate, until it reaches a constant value at fully developed conditions.

Entropy generation analysis for microscale forced convection with radiation in thermal entrance region

2014 ◽  
Vol 51 (3) ◽  
pp. 307-312 ◽  
Author(s):  
Cyrus Aghanajafi ◽  
Maziar Alasvand Bakhtiarpoor ◽  
Mehran Taghipour ◽  
Farid Mohamadi
Keyword(s):  
Forced Convection ◽  
Entropy Generation ◽  
Entrance Region ◽  
Thermal Entrance Region ◽  
Thermal Entrance

Entropy generation of laminar-forced convection along the wavy surface

2010 ◽  
Vol 7 (5) ◽  
pp. 564 ◽  
Author(s):  
Cha'o Kuang Chen ◽  
Yue Tzu Yang ◽  
Kuei Hao Chang
Keyword(s):  
Forced Convection ◽  
Entropy Generation ◽  
Wavy Surface ◽  
Laminar Forced Convection

Analytical solution of MHD micropolar nanofluid flow and forced convection heat transfer with entropy generation analysis past a linearly stretching sheet

2021 ◽  
Author(s):  
Sina Sadighi ◽  
Hossein Afshar ◽  
Mohsen Jabbari ◽  
Hossein Ahmadi danesh ashtiani
Keyword(s):  
Angular Velocity ◽  
Forced Convection ◽  
Entropy Generation ◽  
Stretching Sheet ◽  
Convection Heat ◽  
Local Skin ◽  
Entropy Generation Number ◽  
Temperature Distributions ◽  
Generation Number ◽  
Micropolar Nanofluid

Abstract This perusal attempts to model and interpret the entropy generation analysis and the flow field of 2-D, steady, viscous, incompressible and laminar boundary layer and forced convection heat transport of micropolar ferrofluid past a stretching sheet including suction and normal magnetic field effects. The porous sheet’s velocity and temperature are presumed to change linearly. Exact explicit solutions of the velocity, angular velocity and temperature distributions have been derived. The impacts of physical parameters on the local skin friction coefficient, the local Nusselt number, the entropy generation number further the velocities and temperature distributions are analyzed by tables and graphs. The angular velocity has more value than velocity for the least value of the magnetic and material parameters. The entropy generation number has a direct relation with material parameter and Brinkman either Reynolds numbers. Moreover, an inverse relation with the Prandtl number.

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