Natural convection in a square enclosure with a circular cylinder according to the bottom wall temperature variation

Purpose This paper aims to study analytically and numerically the problem of transient natural convection heat transfer in a trapezoidal cavity with spatial side-wall temperature variation. Design/methodology/approach The governing equations subject to the initial and boundary conditions are solved numerically by the finite difference scheme consisting of the alternating direction implicit method and the tri-diagonal matrix algorithm. The left sloping wall of the cavity is heated to non-uniform temperature, and the right sloping wall is maintained at a constant cold temperature, while the horizontal walls are kept adiabatic. Findings It is shown that the heat transfer rate increases in non-uniform heating increments, whereby low wave number values are more affected by the convection. The best heat transfer enhancement results from larger side wall inclination angle; however, trapezoidal cavities require longer time compared to that of square to reach steady state. Originality/value The study of natural convection heat transfer in a trapezoidal cavity filled with nanofluid and heated by spatial side-wall temperature has not yet been undertaken. Thus, the authors of the present study believe that this work is valuable.

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Numerical Investigation of Natural Convection and Surface Radiation in an Air Filled Square Enclosure with a Wavy Bottom Wall

Afyon Kocatepe University Journal of Sciences and Engineering ◽

10.5578/fmbd.67764 ◽

2018 ◽

Vol 18 (3) ◽

pp. 1137-1148

Author(s):

Mesut Tekkalmaz

Keyword(s):

Natural Convection ◽

Numerical Investigation ◽

Surface Radiation ◽

Bottom Wall ◽

Square Enclosure

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A lattice Boltzmann analysis of the conjugate natural convection in a square enclosure with a circular cylinder

Applied Mathematical Modelling ◽

10.1016/j.apm.2019.02.012 ◽

2019 ◽

Vol 71 ◽

pp. 31-44 ◽

Cited By ~ 16

Author(s):

Lei Wang ◽

Yong Zhao ◽

Xuguang Yang ◽

Baochang Shi ◽

Zhenhua Chai

Keyword(s):

Natural Convection ◽

Circular Cylinder ◽

Lattice Boltzmann ◽

Square Enclosure ◽

Conjugate Natural Convection

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Numerical computation of natural convection inside a curved-shape nanofluid-filled enclosure with nonuniform heating of the bottom wall

International Journal of Modern Physics C ◽

10.1142/s0129183119500062 ◽

2019 ◽

Vol 30 (01) ◽

pp. 1950006 ◽

Cited By ~ 2

Author(s):

Abdellaziz Yahiaoui ◽

Mahfoud Djezzar ◽

Hassane Naji

Keyword(s):

Heat Transfer ◽

Natural Convection ◽

Rayleigh Number ◽

Volume Fraction ◽

Pure Water ◽

Bottom Wall ◽

Working Fluid ◽

Nonuniform Heating ◽

Square Enclosure ◽

Nusselt Numbers

This paper performs a numerical analysis of the natural convection within two-dimensional enclosures (square enclosure and enclosures with curved walls) full of a H2O-Cu nanofluid. While their vertical walls are isothermal with a cold temperature [Formula: see text], the horizontal top wall is adiabatic and the bottom wall is kept at a sinusoidal hot temperature. The working fluid is assumed to be Newtonian and incompressible. Three values of the Rayleigh number were considered, viz., 103, 104, 105, the Prandtl number is fixed at 6.2, and the volume fraction [Formula: see text] is taken equal to 0% (pure water), 10% and 20%. The numerical simulation is achieved using a 2D-in-house CFD code based on the governing equations formulated in bipolar coordinates and translated algebraically via the finite volume method. Numerical results are presented in terms of streamlines, isotherms and local and average Nusselt numbers. These show that the heat transfer rate increases with both the volume fraction and the Rayleigh number, and that the average number of Nusselt characterizing the heat transfer raises with the nanoparticles volume fraction.

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