The Effect of Asymmetrically Confined Circular Cylinder and Opposing Buoyancy on Fluid Flow and Heat Transfer

2017 ◽  
Vol 374 ◽  
pp. 18-28 ◽  
Author(s):  
Houssem Laidoudi ◽  
Mohamed Bouzit
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Transfer Rate ◽  
Richardson Number ◽  
Convection Heat Transfer ◽  
Heat Transfer Characteristics ◽  
Thermal Buoyancy ◽  
Flow And Heat Transfer ◽  
Mixed Convection Heat Transfer

In this paper, a two-dimensional numerical investigation is carried out to understand the effects of opposing thermal buoyancy and Prandtl number on fluid flow and mixed convection heat transfer characteristics of symmetrically and asymmetrically confined cylinder submerged in Newtonian fluid. The detailed flow and temperature field are illustrated in term of streamlines and isotherm contours to interpret the flow and thermal transport visualization. The numerical results are presented and discussed for the range of conditions as: Ri = 0 to -4, Pr = 0.7 to 50, eccentricity factor ε = 0 to 0.7 at Re = 40 and for a fixed blockage parameter B = 0.2. The effect of opposing buoyancy is brought about by varying Richardson numbers. The overall drag coefficient and average Nusselt number are computed to elucidate the role of Prandt number, eccentricity factor and Richardson number on the flow and heat transfer. At ε = 0, it is found that, when the buoyancy is opposed the flow becomes asymmetrically and some rotating zones appear under and above the cylinder. Moreover, the eccentricity factor has a tendency to decrease the rotating regions and to increase the heat transfer rate. For example an increase in eccentricity factor from 0 to 0.6 increases Nu by 77% at Ri = 4.

Numerical Investigation of Mixed Convection Heat Transfer in Steady Flow Past a Row of Three Square Cylinders

2018 ◽  
Vol 389 ◽  
pp. 164-175
Author(s):  
Houssem Laidoudi ◽  
Bilal Blissag ◽  
Mohamed Bouzit
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Mixed Convection ◽  
Convection Heat Transfer ◽  
Convection Heat ◽  
Thermal Buoyancy ◽  
Flow And Heat Transfer ◽  
Square Cylinders ◽  
Laminar Mixed Convection ◽  
Mixed Convection Heat Transfer

In this paper, the numerical simulations of laminar mixed convection heat transfer from row of three isothermal square cylinders placed in side-by-side arrangement are carried out to understand the behavior of fluid flow around those cylinders under gradual effect of thermal buoyancy and its effect on the evacuation of heat energy. The numerical results are presented and discussed for the range of these conditions: Re = 10 to 40, Ri = 0 to 2 at fixed value of Prandtl number of Pr = 1 and at fixed geometrical configuration. In order to analyze the effect of thermal buoyancy on fluid flow and heat transfer characteristics the main results are illustrated in terms of streamline and isotherm contours. The total drag coefficient as well as average Nusselt number of each cylinder are also computed to determine exactly the effect of buoyancy strength on hydrodynamic force and heat transfer evacuation of each cylinder.

Mixed Convection Heat Transfer around a Tandem Circular Cylinders in Incompressible Downward Flow

2018 ◽  
Vol 16 ◽  
pp. 12-20
Author(s):  
Houssem Laidoudi ◽  
Oluwole Daniel Makinde
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Convection Heat Transfer ◽  
Vertical Channel ◽  
Circular Cylinders ◽  
Thermal Buoyancy ◽  
Flow And Heat Transfer ◽  
Mixed Convective Flow

In this paper, we numerically examine the mixed convective flow around a confined tandem heated circular cylinders embedded in a vertical channel in order to determine exactly the effects of opposing thermal buoyancy and distance between cylinders (S) on the behavior of fluid flow and heat transfer rate. The dimensionless governing equations involving momentum, continuity and energy are obtained and solved in a steady laminar flow regime for the conditions:Re= 5 to 40 andS= 0 to 5d, at fixed values of Prandtl numberPr= 1, Richardson numberRi= 1 and blockage ratioβ= 1/5. The fluid flow and temperature field are illustrated in terms of streamline and isotherm contours. The average Nusselt number is also computed to quantify the effect of fluid flow and heat transfer characteristics on amount of heat transfer rate.

The Effect of Blockage Ratio on Fluid Flow and Heat Transfer around a Confined Square Cylinder under the Effect Thermal Buoyancy

2018 ◽  
Vol 16 ◽  
pp. 1-11
Author(s):  
Houssem Laidoudi
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Numerical Study ◽  
Convection Heat Transfer ◽  
Blockage Ratio ◽  
Square Cylinder ◽  
Total Drag ◽  
Thermal Buoyancy ◽  
2D Simulation ◽  
Flow And Heat Transfer

2D simulation is carried out to determine exactly the effect of blockage ratio on the flow and mixed convection heat transfer characteristics of Newtonian fluid across a square cylinder confined in horizontal channel, the numerical study is investigated in the range of these conditions:Re= 10 to 30,Ri= 0 to 1 and blockage ratioβ= 1/10 to 1/2. The flow structure and temperature field are visualized in terms of streamlines and isotherm contours. The total drag coefficient and average Nusselt number are also reported to show the combined effects of thermal buoyancy, Reynolds number and blockage ratio on the hydrodynamic flow forces and heat transfer rate. The obtained results showed that the effect of thermal buoyancy on fluid flow and heat transfer becomes more pronounced by decreasing the blockage ratio.

scholarly journals Mixed convection heat transfer from a heated circular cylinder

2019 ◽  
Vol 54 (1) ◽  
pp. 83-88
Author(s):  
H Laidoudi ◽  
M Bouzit
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Drag Coefficient ◽  
Average Nusselt Number ◽  
Convection Heat Transfer ◽  
Circular Cylinders ◽  
Governing Equations ◽  
Thermal Buoyancy ◽  
Flow And Heat Transfer ◽  
Mixed Convection Heat Transfer

This paper performs the effects of thermal buoyancy and the triangular arrangement of circular cylinders on fluid flow and heat transfer within a horizontal channel, the governing equations involving continuity; momentum and energy are solved in two-dimensional, laminar and steady flow regime. The average Nusselt number and drag coefficient are computed for the range of these conditions: Ri = 0 to 2 at fixed value of Pr = 1, Reynolds number Re = 30 and geometrical configurations (blockage ratio of β = 0.1). In order to observe the flow structure and temperature field under the gradual effect of thermal buoyancy, the streamlines and isotherm contours are illustrated. It is found that, a gradual increase in the value of buoyancy strength creates an asymmetrical flow around the cylinders. Interesting variations of drag coefficient and average Nusselt number are plotted with respect to Richardson number for each cylinder. Bangladesh J. Sci. Ind. Res.54(1), 83-88, 2019

Buoyancy-induced flow and heat transfer in multilayered cavities with openings

2018 ◽  
Vol 28 (8) ◽  
pp. 1774-1790 ◽  
Author(s):  
Jiaolin Wang ◽  
Ye Zhou ◽  
Qi-Hong Deng
Keyword(s):  
Heat Transfer ◽  
Convection Heat Transfer ◽  
Simple Algorithm ◽  
Content Type ◽  
Thermal Buoyancy ◽  
Flow And Heat Transfer ◽  
Flow Interaction ◽  
Single Side ◽  
Open Cavities

Purpose The purpose of this study is to investigate the flow interaction between the cavities and its impact on heat transfer. The role of the openings is examined and three strategies are considered: one opening, two openings on single side and two openings on double sides. Design/methodology/approach A two-dimensional laminar natural convection heat transfer in multilayered open cavities was numerically investigated. The governing equations in primitive variables were discretized by the finite volume method and solved by SIMPLE algorithm. Findings The results show that for the cavities with one opening, the flow in the cavities is connected with each other. The exhaust hot fluid from the lower cavity was entrained into the upper cavities by thermal buoyancy and hence the heat transfer in the upper cavities was decreased because of thermal accumulation. Two openings on the single side could strengthen the flow interaction between the cavities and then enhance the heat transfer. However, the double-sided openings eliminated the flow interaction between the cavities and thus the fluid flow and heat transfer characteristics in all cavities are independent. It was concluded that the flow interaction between the multilayered open cavities has an importance effect on the heat transfer in the cavities. Originality/value The flow interaction between the multilayered open cavities was illustrated. The effect of flow interaction on the heat transfer in the cavities was investigated. The role of openings in the flow interaction and heat transfer in cavities was explored. The cavity below affects above cavity for the openings on single side. No interaction exists between the cavities with openings on double sides.

Simulation of Non Newtonian Power-Law Fluid Flows and Mixed Convection Heat Transfer inside of Curved Duct

2017 ◽  
Vol 378 ◽  
pp. 113-124 ◽  
Author(s):  
Bouzit Fayçal ◽  
Houssem Laidoudi ◽  
Mohamed Bouzit
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Rate ◽  
Power Law ◽  
Transfer Rate ◽  
Richardson Number ◽  
Flow Behavior ◽  
Thermal Buoyancy ◽  
Flow And Heat Transfer ◽  
Curved Duct ◽  
Power Law Fluids

A two-dimensional numerical simulation is carried out to understand the combined effects of thermal buoyancy strength and rheological flow behavior of non Newtonian power-law fluids on laminar flow and heat transfer rate through a 180° curved duct. The governing equations including the full Navier-Stokes, the continuity and the energy are solved using the commercial code ANSYS-CFX. The numerical results are presented and discussed for the range of conditions as: Re = 40 to 1000, Ri = 0 to 1 and n = 0.4 to 1.2 for fixed value of Prandt number of Pr = 1. In order to analyze the obtained results, the representative streamlines and isotherm patterns are presented. The average Nusselt number of the inner and outer walls of duct is computed to determine the role of Reynolds number, Richardson number and power-law index on flow and heat transfer. It is found that increase in Richardson number creates alternative vortices on duct walls. Moreover, the alternative vortices enhance the heat transfer rate for shear thinning, Newtonian and shear thickening fluids.

Effect of Variable Sidewall Temperatures on the Combined Surface Radiation—Convection in a Discretely Heated Enclosure

2018 ◽  
Vol 140 (9) ◽  
Author(s):  
S. Saravanan ◽  
N. Raja
Keyword(s):  
Heat Transfer ◽  
Transfer Rate ◽  
Surface Radiation ◽  
Computational Results ◽  
Heat Transfer Characteristics ◽  
Total Heat Transfer ◽  
Flow And Heat Transfer ◽  
Volume Method ◽  
Made In

This paper reports the changes made in the flow and heat transfer characteristics of a closed enclosure in the presence of sidewalls with symmetrical linear heating. The flow inside the enclosure is primarily driven by a centrally placed discrete heater with thermal radiation included at all surfaces involved. Finite volume method-based computational results corresponding to the resulting steady-state were obtained. The factors causing augmentation and suppression of heat transfer are discussed for two types of sidewall heating. Moreover, it is found that the role of radiation is well stronger than convection in determining the total heat transfer rate when the sidewall heating is decreasing with height.

The Flow and Mixed Convection around Tandem Circular Cylinders at Low Reynolds Number

2017 ◽  
Vol 378 ◽  
pp. 59-67
Author(s):  
Houssem Laidoudi ◽  
Blissag Bilal ◽  
Mohamed Bouzit
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Mixed Convection ◽  
Drag Coefficient ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Richardson Number ◽  
Circular Cylinders ◽  
Thermal Buoyancy ◽  
Flow And Heat Transfer

A numerical investigation is carried out to understand the effects of thermal buoyancy and Reynolds number on flow characteristics and mixed convection heat transfer over three isothermal circular cylinders situated in a tandem arrangement within a horizontal channel. The distance between cylinders is fixed at the value of 2.5 widths of the cylinder. The obtained results are presented and discussed for the range of conditions as: Re = 5 to 40, Ri = 0 to 2 at fixed Pr number of 1 and blockage ratio β = 0.25. The main results are depicted in terms of streamlines and isotherm contours to analyze the effect of thermal buoyancy on fluid flow and heat transfer rate. Moreover, the overall drag coefficient and Nusselt number are computed to elucidate the role of Reynolds number and Richardson number on the flow and heat transfer. It is found that increase in the Richardson number increases the drag coefficient of the upstream cylinder whereas it decreases the heat transfer rate of this cylinder. The superimposed of thermal buoyancy created a new sort of recirculation zones between the tandem cylinders.

scholarly journals Effect of thermal buoyancy on flow pattern from a pair of side-by-side confined triangular cylinders

2020 ◽  
Vol 55 (1) ◽  
pp. 9-14
Author(s):  
H Laidoudi ◽  
M Bouzit
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Drag Coefficient ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Richardson Number ◽  
Average Nusselt Number ◽  
Convection Heat Transfer ◽  
Thermal Buoyancy ◽  
Energy Equations

The effects of ax ial and radial thermal buoyancy on fluid flow and mixed convection heat transfer from a pair of identical triangular cylinders in side-by-side arrangement confined within a straight channel. The numerical simulations are carried out by solving continuity, momentum and energy equations using the commercial code ANSYS-CFX. The obtained results are presented and discussed within the range of following conditions: Richardson number Ri = 0 to 2, Reynolds Re = 20, and Prandtl number Pr = 1 at fixed value of blockage ratio β = 0.2. The main results are depicted in terms of streamline and isotherm contours to analyze the fluidic and energetic behaviors. The total drag coefficient and average Nusselt number are also computed. Moreover, a simple correlation indicating the variations of drag coefficient and average Nusselt number versus Richardson number are also provided. It was found that for axial effect of thermal buoyancy, increase in buoyancy strength enhances the heat transfer rate for both cylinders. In other hand, for radial effect, increase in buoyancy strength increases the heat transfer rate of down cylinder and it is reduced for the upper cylinder. Bangladesh J. Sci. Ind. Res.55(1), 9-14, 2020

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