Numerical modeling flow and heat transfer in dimpled cooling channels with secondary hemispherical protrusions

Liu, Jian; Song, Yidan; Xie, Gongnan; Sundén, Bengt

doi:10.1016/j.energy.2014.05.075

Cited by 67 publications

(13 citation statements)

References 32 publications

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“…Protruded surfaces are classified as one of the passive heat transfer enhancement methods and can significantly enhance the heat transfer by reducing the thermal resistance of the sublayer adjacent to the solid walls. This is done by generating secondary flows, disrupting the boundary layer growth, flow recirculation and shear-layer reattachment, promoting mixing and increasing the turbulence intensity [4]. In the other hand, using protruded surfaces in thermal systems causes a higher pressure drop due to the losses induced by secondary flow, increasing shear-stresses and velocity gradients, and intensive interactions between vortices and the channel walls [5].…”

Section: Introductionmentioning

confidence: 99%

An investigation on thermo-hydraulic performance of a flat-plate channel with pyramidal protrusions

Ebrahimi

Naranjani

2016

Applied Thermal Engineering

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h i g h l i g h t sPyramidal protrusions are proposed for heat transfer enhancement applications. CFD is used to study the hydrothermal performance of the proposed surface pattern. The overall performance of a flat-plate channel is enhanced. The obtained results are investigated using entropy generation analysis. a b s t r a c tIn this study, a flat-plate channel configured with pyramidal protrusions are numerically analysed for the first time. Simulations of laminar single-phase fluid flow and heat transfer characteristics are developed using a finite-volume approach under steady-state condition. Pure water is selected as the coolant and its thermo-physical properties are modelled using a set of temperature-dependent functions. Different configurations of the channel, including a plain channel and a channel with nature-inspired protruded surfaces, are studied here for Reynolds numbers ranging from 135 to 1430. The effects of the protrusion shape, size and arrangement on the hydrothermal performance of a flat-plate channel are studied in details. The temperature of the upper and lower surfaces of the channel is kept constant during the simulations. It is observed that utilizing these configurations can boost the heat transfer up to 277.9% and amplify the pressure loss up to 179.4% with a respect to the plain channel. It is found that the overall efficiency of the channels with pyramidal protrusions is improved by 12.0-169.4% compared to the plain channel for the conditions studied here. Furthermore, the thermodynamic performance of the channel is investigated in terms of entropy generation and it is found that equipping the channels with pyramidal protrusions leads to lower irreversibility in the system.

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Section: Introductionmentioning

confidence: 99%

An investigation on thermo-hydraulic performance of a flat-plate channel with pyramidal protrusions

Ebrahimi

Naranjani

2016

Applied Thermal Engineering

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“…where q″ represents the heat flux, and ΔT -the average temperature difference between the wall and the fluids [3,20,21]. The whole TP factor considers both the heat transfer and the friction resistance, which is described as:…”

Section: Governing Equations and Data Reductionmentioning

confidence: 99%

Genetic algorithm-based heat transfer enhancement technique of a protruded micro-channel

2019

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As an innovative type of passive flow control structure, the protrusion exhibits great potential for heat transfer enhancement. In this paper, genetic algorithm is used for the dimensional optimization of a protruded micro-channel. The protruded micro-channel is studied at four mass-flow rates. In all the cases, thermal performance is selected as the objective function that represents both heat transfer and flow friction. The radius of the protrusion and the distance are selected as the two optimized parameters, and their ranges are decided by physical topologies. The objective function thermal performance is calculated by an auto-CFD batch program. The results shows that there are two peaks of thermal performance values when R and δ change in the cases with flow rates equaling 4 ⋅ 10-5 kg/s and 6 ⋅ 10-5 kg/s, while at the other two flow rates, the thermal performance values increase monotonously. The global optimal solutions for the four flow rates and two local optimal solutions are given in this research, and it is helpful to choose the best design variables to achieve the highest thermal performance. It also can be found that at all the different flow rates, the optimized shape of micro-channel has the same point that (R-δ) is nearly 45 µm in the studied ranges of optimized parameters.

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“…In the literature, one can find numerous works devoted to the intensification of heat exchange between a solid surface and a liquid flow along it due to the formation of indentations -dimples on the surface [1][2][3][4][5][6][7][8][9][10]. It was established that such surface profiling leads to the generation of non-stationary vortex structures in the flow, mixing of the liquid, and, as a result, noticeable intensification of heat exchange as compared with a smooth surface.…”

Section: Introductionmentioning

confidence: 99%

Heat Exchange Between Air and a Liquid Film Flowing Down Along a Profiled Surface

Dubrovsky¹,

Shraiber²

2020

IJHT

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The laws of heat exchange between air and a liquid film flowing down along a solid surface with spherical dimples were investigated experimentally. Three cases of heat transfer were considered: quiescent air, air – liquid counter flow, or their cross flow. In all cases, a significant growth of the heat exchange intensity, especially at air – liquid cross flow, was observed. This is caused by the substantial turbulization of flow and mixing of liquid layers in the film. As a result, it was established that surface profiling (manufacture of dimples) under the optimal conditions leads to an increase in heat exchange intensity by an unexpended factor of 2.5 – 2.8 as compared with a smooth surface, other conditions being equal. The obtained experimental data were generalized in the form of dimensionless dependences Nu vs. Re. The best heat transfer surface can be recommended for use in different heat exchangers.

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Numerical modeling flow and heat transfer in dimpled cooling channels with secondary hemispherical protrusions

Cited by 67 publications

References 32 publications

An investigation on thermo-hydraulic performance of a flat-plate channel with pyramidal protrusions

An investigation on thermo-hydraulic performance of a flat-plate channel with pyramidal protrusions

Genetic algorithm-based heat transfer enhancement technique of a protruded micro-channel

Heat Exchange Between Air and a Liquid Film Flowing Down Along a Profiled Surface

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