On flow structure, heat transfer and pressure drop in varying aspect ratio two-pass rectangular channel with ribs at 45°

Siddique, Waseem; Shevchuk, Igor V.; El-Gabry, Lamyaa A.; Hushmandi, Narmin Baagherzadeh; Fransson, Torsten

doi:10.1007/s00231-013-1111-5

Cited by 66 publications

(10 citation statements)

References 36 publications

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“…The first cell height for each mesh was as follows: 54 μm for the coarse mesh, 51.4 μm for the medium density mesh and 49.0 μm for the fine mesh, which corresponds to y+ values between 0.78 and 0.86. The solution's independence from the mesh was confirmed by comparing the calculation results on all three meshes for the case of 100 W and using the k-ε EWT turbulence model in a similar way as previously demonstrated by Siddique et al[31,32].…”

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confidence: 69%

Experimental and numerical heat transfer analysis of heat-pipe-based CPU coolers and performance optimization methodology

Može

Nemanič

Poredoš

2020

Applied Thermal Engineering

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This paper presents an experimental and numerical heat transfer analysis of heat-pipe-based CPU coolers and a performance optimization methodology. The first part of the study focuses on the performance of two commercial HP-based CPU coolers under inclination angles of 0°, 90° and 180°. The results show that the 90° orientation provides the best thermal performance. The influence of heat pipe orientation on the performance of the entire system is obscured due to the much higher thermal resistance on the air-side of the cooler. A fourfold increase in air volumetric flow rate has only a minor effect on the cooling performance enhancement with a reduction of the thermal resistance from 0.11 K W-1 to 0.074 K W-1 at the highest heating power. In the second part of the study, heat transfer numerical simulations of the finned part of a cooler were performed and validated using experimental results. The output of the simulation is a 2-D temperature field, which is used as an input for the optimization methodology based on fin effectiveness and fin efficiency. Optimizing the fin geometry by removing unnecessary material yielded a 23% increase of the fin efficiency and decreased the weight of a fin by approx. 30%, proving the usefulness of the proposed methodology, which helps reduce costs, weight and development time of finned HP-based coolers.

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supporting

confidence: 69%

Experimental and numerical heat transfer analysis of heat-pipe-based CPU coolers and performance optimization methodology

Može

Nemanič

Poredoš

2020

Applied Thermal Engineering

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“…The coefficient obtained under various resolutions does not show much difference, i.e., a relative difference of less than 0.2% between the results obtained at the 256 × 128 and 512 × 256 grid, thus the 512 × 256 grid was deemed sufficient for this simulation. In this work, we performed a grid sensitivity study for the H•W/D 2 = 0.04 cases with a square cylinder (H/D = W/D = 0.2), a vertically placed plate with H/D = 0.8, and a horizontally placed plate with W/D = 0.8 using the 256 × 256, 512 × 256, and 512 × 512 grids following the manner described in [28,29]. The computed mean Nusselt numbers on the enclosure surface are given in Table 3.…”

Section: Methodsmentioning

confidence: 99%

Effect of Orientation and Aspect Ratio of an Internal Flat Plate on Natural Convection in a Circular Enclosure

Wang

Ying²,

Wang³

et al. 2019

Processes

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This work presents a numerical investigation on natural convection in a circular enclosure with an internal flat plate at Ra = 106. The cross-section area of the plate was fixed at three values, H·W/D2 = 0.01, 0.04, and 0.09, in which H and W are the height and width of the plate and D is the diameter of the enclosure while the aspect ratio changes, which makes the plate vertically placed (H > W) or horizontally placed (H < W). The objective of this work was to explore the effects of the orientation and aspect ratio of the plate on the characteristics of natural convection in various aspects. The numerical results reveal that the overall heat transfer rate is higher for the vertically placed plate and increases with the cross-section area, while the width of the plate has almost no effect for the horizontally placed plate, especially for the plate with a relatively large cross-section area. Depending on the orientation and aspect ratio, there can be one primary vortex, one primary and one secondary vortex, or one secondary and two separated vortices to each side of the plate, and the thermal plume structure may appear at the sharp top corners of the plate. Consequently, local heat transfer on the surfaces of the enclosure and plate is affected. Synergy analysis reveals that the enhancement of heat transfer from the fluid circulation is the most significant at the center of the vortices and at the boundary between them.

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“…It is obvious that rotation has a substantial impact on the heat transfer enhancement because it can cause flow spreading in the spanwise direction and hence enhancing the spanwise heat transfer. The normalized Nusselt number ( ) is used to evaluate the performance of heat transfer from a surface [28], [29], [33].…”

Section: Re=3000mentioning

confidence: 99%

Effect of rotation on forced convection in wavy wall channels

Al-Zurfi

Alhusseny

Nasser

2020

International Journal of Heat and Mass Transfer

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In this paper, flow field and heat transfer performance in stationary and rotating wavy channels with different shapes were numerically investigated. Three different geometries were generated through three different values of phase-shift angles of = 0, 90 and 180 degrees between ∅ the two opposite wavy walls. A cell-centred finite-volume technique was employed to solve the three-dimensional governing equations based on the SIMPLE algorithm technique. Besides, the Menter k-SST turbulence model was used to simulate the turbulent flow in the current study. The wavelength and wave amplitude of the channel examined were L w =20 mm and a=2 mm, respectively. Numerical simulations were carried out over a range of design and operating conditions including the phase-shift angle of = 0-180 degrees, Reynolds number of Re=1,000-∅ 10,000, and rotating speed of 0-1000 rpm. The results showed that the surface-averaged Ω = Nusselt number increases as Re increases for all shapes of the wavy channel, however, at the expense of the raised pressure losses. Also, the wavy channel with a phase-shift of = 0 deg ∅ showed the highest enhancement in the performance of heat transfer followed by that of 90 ∅ = and 180 deg, respectively. The rotation had a strong impact on the flow field and heat transfer performance. With the increase of rotating speed, lower wall heat transfer coefficient significantly increased, while the upper wall heat transfer coefficient exhibited a slight increase, indicating that those three different geometries of the wavy channels had a good versatility at various values of rotating speeds. The numerical results were compared with those available in the literature, and the results were in a good agreement.

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On flow structure, heat transfer and pressure drop in varying aspect ratio two-pass rectangular channel with ribs at 45°

Cited by 66 publications

References 36 publications

Experimental and numerical heat transfer analysis of heat-pipe-based CPU coolers and performance optimization methodology

Experimental and numerical heat transfer analysis of heat-pipe-based CPU coolers and performance optimization methodology

Effect of Orientation and Aspect Ratio of an Internal Flat Plate on Natural Convection in a Circular Enclosure

Effect of rotation on forced convection in wavy wall channels

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