Numerical Analysis on the Effect of Wavy Partitions on Natural Convection in Porous Enclosure

2020 ◽  
Vol 142 (9) ◽  
Author(s):  
Jayesh Subhash Chordiya ◽  
Ram Vinoy Sharma
Keyword(s):  
Natural Convection ◽  
Convection Heat Transfer ◽  
Sine Wave ◽  
Flow In Porous Media ◽  
Governing Equations ◽  
Wave Shape ◽  
Square Wave ◽  
Wide Range ◽  
Replacement Scheme ◽  
Porous Enclosure

Abstract The influence of partitions on natural convection in a differentially heated porous enclosure has been investigated for three different partition shapes, namely, sine-wave, corrugated and square-wave shape. The objective is to identify the best partition shape with regard to achieve maximum reduction in the rate of convection heat transfer. Darcy flow model has been used to describe flow in porous media. Coordinate transformation has been used to formulate the governing equations for sine-wave partition owing to its wavy nature. To assess the effectiveness of various partition shapes, the results are compared with porous enclosure without partition and with straight partition. The governing equations are solved using the successive accelerated replacement scheme for a wide range of parameters like partition amplitude, position, Rayleigh number, enclosure aspect ratio (AR), and inclination angle. One of the findings reveals that for the same amplitude and position, the square-wave partition yields the maximum suppression in the value of Nusselt number.

Conjugate Natural Convection in Porous Medium With a Thick Square-Wave Partition

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Jayesh Subhash Chordiya ◽  
Ram Vinoy Sharma
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Natural Convection ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Convection Heat Transfer ◽  
Thermal Conductivity Ratio ◽  
Convection Heat ◽  
Square Wave ◽  
Porous Enclosure

Abstract Natural convection within a differentially heated porous enclosure is substantially affected by the presence of partition, fins, or baffles within it. However, not much is known about the effect of partition shape and size. Thus, a solid thick partition in a square-wave shape embedded within a differentially heated porous enclosure has been investigated in this numerical analysis. Through this study, it is sought to contemplate the reduction in the convection heat transfer rate that could be achieved across a differentially heated porous enclosure. The influence of partition thickness, partition amplitude, thermal conductivity ratio, and partition position has been studied. Darcy’s flow model has been solved using the successive accelerated replacement scheme by the finite difference method. One of the findings of this study suggests that lower thermal conductivity of partition, lower partition amplitude, and higher thickness results in a greater reduction in the convection heat transfer rate.

Natural Convection Heat Transfer From an Isothermal Vertical Surface to a Stable Thermally Stratified Fluid

1992 ◽  
Vol 114 (4) ◽  
pp. 917-923 ◽  
Author(s):  
D. Angirasa ◽  
J. Srinivasan
Keyword(s):  
Natural Convection ◽  
Thermal Stratification ◽  
Average Nusselt Number ◽  
Convection Heat Transfer ◽  
Stratified Fluid ◽  
Vertical Surface ◽  
Natural Convection Heat Transfer ◽  
Plate Temperature ◽  
Transient Nature ◽  
Wide Range

Natural convection from an isothermal vertical surface to a thermally stratified fluid is studied numerically. A wide range of stratification levels is considered. It is shown that at high levels of ambient thermal stratification, a portion at the top of the plate absorbs heat, while a horizontal plume forms around a location where the plate temperature equals the ambient temperature. The plume is shown to be inherently unsteady, and its transient nature is investigated in detail. The effect of the temperature defect in striating the plume is discussed. Average Nusselt number data are presented for Pr=6.0 and 0.7.

Natural Convection of Cu-Gallium Nanofluid in Enclosures

2011 ◽  
Vol 133 (12) ◽  
Author(s):  
Cong Qi ◽  
Yurong He ◽  
Yanwei Hu ◽  
Juancheng Yang ◽  
Fengchen Li ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Nusselt Number ◽  
Natural Convection ◽  
Aspect Ratio ◽  
Convection Heat Transfer ◽  
Low Velocity ◽  
Grashof Number ◽  
Aspect Ratios ◽  
Wide Range ◽  
Temperature Dependent Properties

In this work, the natural convection heat transfer of Cu-gallium nanofluid in a differentially heated enclosure is investigated. A single-phase model is employed with constant or temperature-dependent properties of the fluid. The results are shown over a wide range of Grashof numbers, volume fractions of nanoparticles, and aspect ratios. The Nusselt number is demonstrated to be sensitive to the aspect ratio. It is found that the Nusselt number is more sensitive to thermal conductivity than viscosity at a low velocity (especially for a low aspect ratio and a low Grashof number), however, it is more sensitive to the viscosity than the thermal conductivity at a high velocity (high aspect ratio and high Grashof number). In addition, the evolution of velocity vectors, isotherms, and Nusselt number for a small aspect ratio is investigated.

Natural Convection Heat Transfer From a Cylinder With High Conductivity Permeable Fins

2003 ◽  
Vol 125 (2) ◽  
pp. 282-288 ◽  
Author(s):  
Bassam A/K Abu-Hijleh
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Rayleigh Number ◽  
Convection Heat Transfer ◽  
High Heat ◽  
Horizontal Cylinder ◽  
High Conductivity ◽  
Transfer Rates ◽  
High Heat Transfer ◽  
Wide Range

The problem of laminar natural convection from a horizontal cylinder with multiple equally spaced high conductivity permeable fins on its outer surface was investigated numerically. The effect of several combinations of number of fins and fin height on the average Nusselt number was studied over a wide range of Rayleigh number. Permeable fins provided much higher heat transfer rates compared to the more traditional solid fins for a similar cylinder configuration. The ratio between the permeable to solid Nusselt numbers increased with Rayleigh number, number of fins, and fin height. This ratio was as high as 8.4 at Rayleigh number of 106, non-dimensional fin height of 2.0, and with 11 equally spaced fins. The use of permeable fins is very advantageous when high heat transfer rates are needed such as in today’s high power density electronic components.

scholarly journals Double-Diffusive of Natural Convection in an Inclined Porous Square Domain Generalized Model

2019 ◽  
Vol 12 (3) ◽  
pp. 151-160
Author(s):  
Khaled Al-Farhany ◽  
A. Turan
Keyword(s):  
Natural Convection ◽  
Lewis Number ◽  
Boussinesq Approximation ◽  
Darcy Number ◽  
Governing Equations ◽  
Simpler Algorithm ◽  
Wide Range ◽  
Finite Volume Approach ◽  
Buoyancy Ratio ◽  
Double Diffusive

Numerical investigate of double-diffusive natural convection in an inclined porous square. Two opposing walls of the square cavity are adiabatic; while the other walls are, kept at constant concentrations and temperatures. The Darcy–Forchheimer–Brinkman model is used to solve the governing equations with the Boussinesq approximation. A code written in FORTRAN language developed to solve the governing equations in dimensionless forms using a finite volume approach with a SIMPLER algorithm. The results presented in U-velocity and V-velocity, isotherms, iso-concentration, streamline, the average Nusselt number, and the average Sherwood number for different values of the dimensionless parameters. A wide range of these parameters have been used including; Darcy Number, modified Rayleigh number, Lewis number, buoyancy ratio, and inclination angle.  The results show that for opposite buoyancy ratio (N≤-1), the Nu decreases when the Le increases and the Sh increase when the Le increases. For an (N>0), the Nu increases when the Le increases until Le is equal to 1 and then it decreases, also Sh increases when the Le increases

scholarly journals Simulation of Natural Convection Heat Transfer in a 2-D Trapezoidal Enclosure

2019 ◽  
Vol 16 (4) ◽  
pp. 7375-7390 ◽  
Author(s):  
K. Venkatadri ◽  
S. Abdul Gaffar ◽  
Ramachandra Prasad V. ◽  
B. Md. Hidayathulla Khan ◽  
O. Anwar Beg
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Rayleigh Number ◽  
Prandtl Number ◽  
Vertical Wall ◽  
Convection Heat Transfer ◽  
Side Wall ◽  
Practical Applications ◽  
Wide Range ◽  
Trapezoidal Enclosure

Natural convection within trapezoidal enclosures finds significant practical applications. The natural convection flows play a prominent role in the transport of energy in energyrelated applications, in case of proper design of enclosures to achieve higher heat transfer rates. In the present study, a two-dimensional cavity with adiabatic right side wall is studied. The left side vertical wall is maintained at the constant hot temperature and the top slat wall is maintained at cold temperature. The dimensionless governing partial differential equations for vorticity-stream function are solved using the finite difference method with incremental time steps. The parametric study involves a wide range of Rayleigh number, Ra, 103 ≤ Ra ≤ 105 and Prandtl number (Pr = 0.025, 0.71 and 10). The fluid flow within the enclosure is formed with different shapes for different Pr values. The flow rate is increased by enhancing the Rayleigh number (Ra = 104 ). The numerical results are validated with previous results. The governing parameters in the present article, namely Rayleigh number and Prandtl number on flow patterns, isotherms as well as local Nusselt number are reported. 

scholarly journals Convection Heat Transfer of MgO-Ag /Water Magneto-Hybrid Nanoliquid Flow into a Special Porous Enclosure

2020 ◽  
Vol 2 (2) ◽  
pp. 84-95
Author(s):  
Fateh Mebarek Oudina ◽  
◽  
Fares Redouane ◽  
Choudhari Rajashekhar ◽  
◽  
...  
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Computational Study ◽  
Convection Heat Transfer ◽  
Darcy Number ◽  
Governing Equations ◽  
Galerkin Finite Element ◽  
Element Technique ◽  
The Magnetic Field ◽  
Porous Enclosure

This work explores numerically a computational study of free convection in a grooved porous enclosure filled with water-based hybrid-nanoliquid in the presence of an external magnetic field. To solve the governing equations of the problem, the Galerkin finite element technique is utilized. For a several governing parameters such as Rayleigh number (102≤Ra ≤106), magnetic field parameter (0≤Ha≤100), Darcy number (10-2≤ Da ≤10-4) the results are obtained and discussed via streamlines, isotherms and average Nusselt number. The magnetic field has a good regulating effect for the fluid flow and the heat transfer in porous media

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