Natural convection heat transfer and entropy generation from a heated cylinder of different geometry in an enclosure with non-uniform temperature distribution on the walls

Bhowmick, Debayan; Randive, Pitambar; Pati, Sukumar; Agrawal, Himanshu; Kumar, Amit; Kumar, P. Vijay

doi:10.1007/s10973-019-09054-2

Cited by 40 publications

(4 citation statements)

References 45 publications

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“…Finite elements have also been widely used. For example, Bhowmick et al [12] used the Galerkin Finite Element Method to discretize the governing equations of natural convection heat transfer and entropy generation for a square enclosure, containing a heated circular or square cylinder subjected to non-uniform temperature distributions on the left vertical and bottom walls. The finite element method was also used by Islam et al [13] to analyze temperature transfer within a prismatic cavity filled with Cu-water nanofluid under two different temperature boundary conditions.…”

Section: Ramentioning

confidence: 99%

Numerical Assessment of Nanofluid Natural Convection Using Local RBF Method Coupled with an Artificial Compressibility Model

Nuwairan¹,

Chaabelasri²

2023

Computer Modeling in Engineering &Amp; Sciences

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In this paper, natural heat convection inside square and equilateral triangular cavities was studied using a meshless method based on collocation local radial basis function (RBF). The nanofluids used were Cu-water or Al 2 O 3 -water mixture with nanoparticle volume fractions range of 0 ≤ φ ≤ 0.2. A system of continuity, momentum, and energy partial differential equations was used in modeling the flow and temperature behavior of the fluids. Partial derivatives in the governing equations were approximated using the RBF method. The artificial compressibility model was implemented to overcome the pressure velocity coupling problem that occurs in such equations. The main goal of this work was to present a simple and efficient method to deal with complex geometries for a variety of problem conditions. To assess the accuracy of the proposed method, several test cases of natural convection in square and triangular cavities were selected. For Rayleigh numbers ranging from 10 3 to 10 5 , a validation test of natural convection of Cu-water in a square cavity was used. The numerical investigation was then extended to Rayleigh number 10 6 , as well as Al 2 O 3 -water nanofluid with a volume fraction range of 0 ≤ φ ≤ 0.2. In a second investigation, the same nanofluids were used in a triangular cavity with varying volume fractions to test the proposed meshless approach on non-rectangular geometries. The numerical results appear to be in agreement with those from earlier investigations. Furthermore, the suggested meshless method was found to be stable and accurate, demonstrating that it may be a viable alternative for solving natural heat transfer equations of nanofluids in enclosures with irregular geometries. KEYWORDSNatural heat convection; nanofluids; cavities; meshless method; radial basis function Abbreviations N Number of nodes Cp Specific heat, J/kg/K g Acceleration due to gravity, m/s 2 k Thermal conductivity, W /mK Nu Nusselt number Pr Prandtl number

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Section: Ramentioning

confidence: 99%

Numerical Assessment of Nanofluid Natural Convection Using Local RBF Method Coupled with an Artificial Compressibility Model

Nuwairan¹,

Chaabelasri²

2023

Computer Modeling in Engineering &Amp; Sciences

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“…Cho et al [12] investigated how heat transfer was affected by the distance in a square cage between each of the cylinders. For various cylinder geometries and wall temperatures, Bhowmick et al [13] looked at the effect of buoyancy on the transfer of thermal energy from an enclosed heated cylinder. Other researchers calculated the heat transfer caused by buoyancy between two heated cylinders inside of an enclosure with side walls and an unevenly cooled bottom [14,15].…”

Section: Introductionmentioning

confidence: 99%

Natural Convection in a Circular Enclosure with Four Cylinders under Magnetic Field: Application to Heat Exchanger

Azzouz,

Hamida

2023

Processes

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This paper documents the 2D numerical study of magnetohydrodynamic unsteady natural convective heat transfer in a circular enclosure with four heating cylinders in both the horizontal and the vertical mid-plane. The fluid is an incompressible Newtonian fluid. The main transport equations based on the conservation of mass, momentum, and energy are calculated and solved using a finite element numerical solver with the following parameter ranges: dimensionless distance between cylinders S = 0.05–0.29, Rayleigh number Ra=103–106, and Hartmann number for Ha = 0–120. COMSOL Multiphysics, a numerical simulation program, was used to solve the governing equations. It was demonstrated that for lower Ra values, heat transfer through an applied magnetic field is unaffected for a specific S value because the mechanism of transport is diffusion, whereas for larger Ra, there is a complex interaction among magnetic field and physical thermal properties. The features of the heat transfer rate are determined by the interaction. The Nusselt number virtually stays constant as Ha rises at smaller Ra. However, at high Ra, the Nusselt number initially declines with Ha and thereafter essentially stays constant, and at high Ra values, the switch from conduction to convective heat transfer takes place. Additionally, Nu rises slightly with S at increasing Ra.

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“…The combination of the conditions of the enclosure and the internal bodies provides various reach topics. Thus, numerous studies have dealt with the natural convection for the internal bodies in the enclosure by considering the individual condition or combined conditions such as the thermal boundary [1][2][3][4][5], the shape [3,4,[6][7][8][9], 3D effect [2,[10][11][12], the size [8,9,11,[13][14][15][16][17][18][19][20][21][22], the number of the internal bodies [23], the concentric and eccentric internal body [12,[23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40], Rayleigh number…”

Section: Introductionmentioning

confidence: 99%

Classification of Flow Modes for Natural Convection in a Square Enclosure with an Eccentric Circular Cylinder

Yoon¹,

Shim²

2021

Energies

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The present study investigated the natural convection for a hot circular cylinder embedded in a cold square enclosure. The numerical simulations are performed to solve a two-dimensional steady natural convection for three Rayleigh numbers of 103, 104 and 105 at a fixed Prandtl number of 0.7. This study considered the wide range of the inner cylinder positions to identify the eccentric effect of the cylinder on flow and thermal structures. The present study classifies the flow structures according to the cylinder position. Finally, the present study provides the map for the flow structures at each Rayleigh number (Ra). The Ra = 103 and 104 form the four modes of the flow structures. These modes are classified by mainly the large circulation and inner vortices. When Ra = 105, one mode that existed at Ra = 103 and 104, disappears in the map of the flow structures. The new three modes appear, resulting in total six modes of flow structures at Ra = 105. New modes at Ra = 105 are characterized by the top side secondary vortices. The corresponding isotherms are presented to explain the bifurcation of the flow structure.

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Natural convection heat transfer and entropy generation from a heated cylinder of different geometry in an enclosure with non-uniform temperature distribution on the walls

Cited by 40 publications

References 45 publications

Numerical Assessment of Nanofluid Natural Convection Using Local RBF Method Coupled with an Artificial Compressibility Model

Numerical Assessment of Nanofluid Natural Convection Using Local RBF Method Coupled with an Artificial Compressibility Model

Natural Convection in a Circular Enclosure with Four Cylinders under Magnetic Field: Application to Heat Exchanger

Classification of Flow Modes for Natural Convection in a Square Enclosure with an Eccentric Circular Cylinder

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