Second Law Analysis Through a Porous Poiseuille–Benard Channel Flow

2015 ◽  
Vol 138 (2) ◽  
Author(s):  
Amel Tayari ◽  
Nejib Hidouri ◽  
Mourad Magherbi ◽  
Ammar Ben Brahim
Keyword(s):  
Heat Transfer ◽  
Finite Element Method ◽  
Channel Flow ◽  
Entropy Generation ◽  
Control Volume ◽  
Second Law ◽  
Brinkman Model ◽  
Second Law Analysis ◽  
Medium Porosity ◽  
Control Volume Finite Element

This paper proposes a numerical analysis of entropy generation during mixed convection inside a porous Poiseuille–Benard channel flow, where the Darcy–Brinkman model is used. Irreversibilities due to heat transfer and viscous dissipation have been derived, and then calculated by numerically solving mass, momentum, and energy conservation equations, by using a control volume finite element method (CVFEM). For a fixed value of the thermal Rayleigh (Ra = 104) and the modified Brinkman (Br* = 10−3) numbers, transient entropy generation exhibits a periodic behavior for the medium porosity ε ≥ 0.2, which is described by the onset of thermoconvective cells inside the porous channel. Highest irreversibility is obtained at ε = 0.5. More details about the effects of the Darcy, the Rayleigh, and the modified Brinkman numbers on entropy generation and heat transfer are discussed and graphically presented.

scholarly journals Analytical Assessment of (Al2O3–Ag/H2O) Hybrid Nanofluid Influenced by Induced Magnetic Field for Second Law Analysis with Mixed Convection, Viscous Dissipation and Heat Generation

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 498
Author(s):  
Wasim Ullah Khan ◽  
Muhammad Awais ◽  
Nabeela Parveen ◽  
Aamir Ali ◽  
Saeed Ehsan Awan ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Viscous Dissipation ◽  
Entropy Generation ◽  
Heat Generation ◽  
Transfer Rate ◽  
Second Law ◽  
Hybrid Nanofluid ◽  
Entropy Generation Number ◽  
Generation Number ◽  
Second Law Analysis

The current study is an attempt to analytically characterize the second law analysis and mixed convective rheology of the (Al2O3–Ag/H2O) hybrid nanofluid flow influenced by magnetic induction effects towards a stretching sheet. Viscous dissipation and internal heat generation effects are encountered in the analysis as well. The mathematical model of partial differential equations is fabricated by employing boundary-layer approximation. The transformed system of nonlinear ordinary differential equations is solved using the homotopy analysis method. The entropy generation number is formulated in terms of fluid friction, heat transfer and Joule heating. The effects of dimensionless parameters on flow variables and entropy generation number are examined using graphs and tables. Further, the convergence of HAM solutions is examined in terms of defined physical quantities up to 20th iterations, and confirmed. It is observed that large λ1 upgrades velocity, entropy generation and heat transfer rate, and drops the temperature. High values of δ enlarge velocity and temperature while reducing heat transport and entropy generation number. Viscous dissipation strongly influences an increase in flow and heat transfer rate caused by a no-slip condition on the sheet.

Second Law Analysis of Spray Evaporation

1990 ◽  
Vol 112 (2) ◽  
pp. 130-135 ◽  
Author(s):  
S. K. Som ◽  
A. K. Mitra ◽  
S. P. Sengupta
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Entropy Generation ◽  
Exergy Analysis ◽  
Droplet Evaporation ◽  
Second Law ◽  
Hot Gas ◽  
Second Law Analysis ◽  
Initial Drop ◽  
Parallel Stream

A second law analysis has been developed for an evaporative atomized spray in a uniform parallel stream of hot gas. Using a discrete droplet evaporation model, an equation for entropy balance of a drop has been formulated to determine numerically the entropy generation histories of the evaporative spray. For the exergy analysis of the process, the rate of heat transfer and that of associated irreversibilities for complete evaporation of the spray have been calculated. A second law efficiency (ηII), defined as the ratio of the total exergy transferred to the sum of the total exergy transferred and exergy destroyed, is finally evaluated for various values of pertinent input parameters, namely, the initial Reynolds number (Rei = 2ρgVixi/μg) and the ratio of ambient to initial drop temperature (Θ∞′/Θi′).

Numerical Study of Transient Convection With Volumetric Radiation Using an Hybrid Lattice Boltzmann Bhatnagar–Gross–Krook–Control Volume Finite Element Method

2017 ◽  
Vol 139 (9) ◽  
Author(s):  
Raoudha Chaabane ◽  
Faouzi Askri ◽  
Abdelmajid Jemni ◽  
Sassi Ben Nasrallah
Keyword(s):  
Heat Transfer ◽  
Finite Element Method ◽  
Finite Element ◽  
Radiative Heat Transfer ◽  
Lattice Boltzmann ◽  
Radiative Heat ◽  
Control Volume ◽  
Double Population ◽  
Control Volume Finite Element ◽  
Element Method

In this paper, a new hybrid numerical algorithm is developed to solve coupled convection–radiation heat transfer in a two-dimensional cavity containing an absorbing, emitting, and scattering medium. The radiative information is obtained by solving the radiative transfer equation (RTE) using the control volume finite element method (CVFEM), and the density, velocity, and temperature fields are calculated using the two double population lattice Boltzmann equation (LBE). To the knowledge of the authors, this hybrid numerical method is applied at the first time to simulate combined transient convective radiative heat transfer in 2D participating media. In order to test the efficiency of the developed method, two configurations are examined: (i) free convection with radiation in a square cavity bounded by two horizontal insulating sides and two vertical isothermal walls and (ii) Rayleigh–Benard convection with and without radiative heat transfer. The obtained results are validated against available works in literature, and the proposed method is found to be efficient, accurate, and numerically stable.

Sign in / Sign up

Export Citation Format

Share Document