Laminar CuO–water nano-fluid flow and heat transfer in a backward-facing step with and without obstacle

Togun, Hussein

doi:10.1007/s13204-015-0441-7

Cited by 27 publications

(7 citation statements)

References 19 publications

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“…The THP factor was found to be varying by 5%–8% with a change in Reynolds number. As a result, it is strongly recommended that the placement of ribs from the channel entry point be considered an important component and should be optimized along with other characteristics, such as rib pitch and thickness 25,26 …”

Section: Discussionmentioning

confidence: 99%

“…The validation of the mathematical formulation and numerical scheme was done by comparing with results reported by Togun et al 25 for a 2D backward‐facing step flow. The variation of the Nusselt number with the Reynolds number, as shown in Figure 3A, demonstrates a good agreement between the current investigation and that of Togun et al 25 with a maximum variation of less than 3%.…”

Section: Validation and Grid‐independent Studymentioning

confidence: 99%

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Two‐dimensional‐numerical investigation on the influence of first rib distance from the entrance of channel on Nusselt number and pressure drop

Shashidhara

Thomas

2022

Heat Trans

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Enhancing the heat transfer coefficient in heat sinks can be achieved by surface modification techniques. Although the addition of ribs increases heat transfer capacity, it also increases pressure drop, lowering the channel's thermohydraulic performance (THP) factor. Rib research began a decade ago, with the majority of studies focusing on new rib designs or factors such as relative roughness pitch, relative roughness height, channel width, and channel height (geometric optimization) to improve THP. The goal of this study is to investigate the influence of the positioning of the first rib from the channel entrance on the Nusselt number, pressure drop, and THP factor with a simple design that could be manufactured easily. Three distinct rib designs are evaluated with rib positioning from the channel entrance, rib thickness, pitch, and Reynolds number as the parameters. It was found that the fluid starts settling up at the ribs as the ribs are moved closer to the channel entry point, thus increasing the pressure drop and reducing the fluid velocity. For the proposed design and dimensions, the Nusselt number increases by 3%-5%, and the pressure drop lowers by 4%-14% when the first rib is placed away from the channel entrance.

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Section: Discussionmentioning

confidence: 99%

Section: Validation and Grid‐independent Studymentioning

confidence: 99%

Two‐dimensional‐numerical investigation on the influence of first rib distance from the entrance of channel on Nusselt number and pressure drop

Shashidhara

Thomas

2022

Heat Trans

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“…They observed results similar to those in the previous experimental studies regarding separation and reattachment length at the top and bottom wall of the tube. Separation and reattachment regions of different fluid-flow over the backward and forward-facing arrangements were investigated by numerous researchers [6][7][8][9][10][11][12], and they achieved similar results.…”

Section: Introductionmentioning

confidence: 95%

Effect of flow separation of TiO2 nanofluid on heat transfer in the annular space of two concentric cylinders

et al. 2020

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In the wake of energy crises, the researchers are encouraged to explore new ways of enhancement in the thermal performance of heat exchanging equipment. In the current research, the SST k-ω model and finite volume method were employed to augment heat transfer into the separation flow of TiO 2 nanofluid in the annular space of two concentric cylinders. In the present investigation TiO 2 nanoparticles of volume fractions, 0.5%-2% at Reynolds number range of 10000-40000, and contraction ratios from 1 to 2 were considered at constant heat flux boundary condition. Simulation results reveal that the highest enhancement in the heat transfer coefficient is corresponding to the annular pipe with a contraction ratio of 2 due to the generated re-circulation flow zone that begins after the separation point on the wall. Further, the surface heat transfer coefficient enhances with the increase of nanoparticles volume fraction and Reynolds number. The velocity distribution profile before and after the steps reveals that increasing the height of the step and Reynolds number, re-circulation regions also increases. Numerical results indicate that the highest pressure drop occurs at the Re = 40000 and contraction ratio of 2.

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“…Also, they conclude that the temperatures at both outlets decreased as the number of inlets increased, while an increase is observed as the radius of the cold outlet is increased. Togun [28] numerically investigated simulation by using the finite volume method, the CuO-nanofluid and heat transfers in a backward-facing step with and without obstacles. The obtained results show that the maximum augmentation in heat transfer was about 22% for the backward-facing step with an obstacle of 4.5 mm and using CuO nanoparticles at a Reynolds number of 225 compared to the backward-facing step without an obstacle.…”

Section: Introductionmentioning

confidence: 99%

Second Law Analysis of MHD Forced Convective Nanoliquid Flow Through a Two-Dimensional Channel

Miri

Abbassi

Ferhi

et al. 2022

Acta Mechanica Et Automatica

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The present study deals with fluid flow, heat transfer and entropy generation in a two-dimensional channel filled with Cu–water nanoliquid and containing a hot block. The nanoliquid flow is driven along the channel by a constant velocity and a cold temperature at the inlet, and the partially heated horizontal walls. The aim of this work is to study the influence of the most important parameters such as nanoparticle volume fraction (0%≤ϕ≤4%), nanoparticle diameter (5 nm≤dp≤55 nm), Reynolds number (50≤Re≤200), Hartmann number (0≤Ha≤90), magnetic field inclination angle (0≤γ≤π) and Brownian motion on the hydrodynamic and thermal characteristics and entropy generation. We used the lattice Boltzmann method (LBM: SRT-BGK model) to solve the continuity, momentum and energy equations. The obtained results show that the maximum value of the average Nusselt number is found for case (3) when the hot block is placed between the two hot walls. The minimum value is calculated for case (2) when the hot block is placed between the two insulated walls. The increase in Reynolds and Hartmann numbers enhances the heat transfer and the total entropy generation. In addition, the nanoparticle diameter increase reduces the heat transfer and the irreversibility, the impact of the magnetic field inclination angle on the heat transfer and the total entropy generation is investigated, and the Brownian motion enhances the heat transfer and the total entropy generation.

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Laminar CuO–water nano-fluid flow and heat transfer in a backward-facing step with and without obstacle

Cited by 27 publications

References 19 publications

Two‐dimensional‐numerical investigation on the influence of first rib distance from the entrance of channel on Nusselt number and pressure drop

Two‐dimensional‐numerical investigation on the influence of first rib distance from the entrance of channel on Nusselt number and pressure drop

Effect of flow separation of TiO2 nanofluid on heat transfer in the annular space of two concentric cylinders

Second Law Analysis of MHD Forced Convective Nanoliquid Flow Through a Two-Dimensional Channel

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