The effects of variable porosity and cell size on the thermal performance of functionally-graded foams

Iasiello, Marcello; Bianco, Nicola; Chiu, Wilson K. S.; Naso, Vincenzo

doi:10.1016/j.ijthermalsci.2020.106696

Cited by 55 publications

(37 citation statements)

References 41 publications

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“…An exhaustive review of the performance enhancement criterion, as an effective tool for measuring heat and fluid flow characteristics, was provided by Yilmaz et al [34]. The PEC has also been indexed in several heat transfer applications [35][36][37][38]. In the context of heat transfer through jet impingement, the thermal-hydraulic performance evaluation was also carried out using the PEC by Choi et al [32].…”

Section: Target Surface Shape and Spacing Between Jet Plate/nozzle And Target Surfacementioning

confidence: 99%

Heat Transfer Augmentation through Different Jet Impingement Techniques: A State-of-the-Art Review

et al. 2021

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Jet impingement is considered to be an effective technique to enhance the heat transfer rate, and it finds many applications in the scientific and industrial horizons. The objective of this paper is to summarize heat transfer enhancement through different jet impingement methods and provide a platform for identifying the scope for future work. This study reviews various experimental and numerical studies of jet impingement methods for thermal-hydraulic improvement of heat transfer surfaces. The jet impingement methods considered in the present work include shapes of the target surface, the jet/nozzle–target surface distance, extended jet holes, nanofluids, and the use of phase change materials (PCMs). The present work also includes both single-jet and multiple-jet impingement studies for different industrial applications.

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Section: Target Surface Shape and Spacing Between Jet Plate/nozzle And Target Surfacementioning

confidence: 99%

Heat Transfer Augmentation through Different Jet Impingement Techniques: A State-of-the-Art Review

et al. 2021

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“…Chen et al [19] showed numerically that in a double-pipe heat exchanger, the best solution was to employ smaller porosities and PPIs at both sides of the inner pipe. Iasiello et al [20] performed a parametric analysis of different porosities and/or PPI distributions in a channel heated from below and equipped with a foam. The Performance Evaluation Criteria (PEC) of graded foams were compared to those of uniform foams with porosities and PPIs the same as their averaged values; increases of up to 38% in the PEC with variable porosity and up to 42% with both variable porosity and PPI were found.…”

Section: Introductionmentioning

confidence: 99%

Mono- and Multi-Objective CFD Optimization of Graded Foam-Filled Channels

et al. 2022

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Graded foam-filled channels are a very promising solution for improving the thermal performance of heat sinks because of their customized structures that leave large amounts of room for heat transfer enhancement. Accordingly, this paper proposes a comprehensive optimization framework to address the design of such components, which are subjected to a uniform heat flux boundary condition. The graded foam is achieved by parameterizing the spatial distributions of porosity and/or Pores Per Inch (PPI). Mono- and multi-objective optimizations are implemented to find the best combination of the foam’s fluid-dynamic, geometrical and morphological design variables. The mono-objective approach addresses the Performance Evaluation Criterion (PEC) as an objective function to maximize the thermal efficiency of graded foams. The multi-objective approach addresses different objective functions by means of Pareto optimization to identify the optimal tradeoff solutions between heat transfer enhancement and pressure drop reduction. Optimizations are performed by assuming a local thermal non-equilibrium in the foam. They allowed us to achieve a 1.51 PEC value with H* = 0.50, ReH = 15000, iε = iPPI = 0.50, ε(0) = 0.85, ε(1) = 0.97, PPI(0) = 5, PPI(1) = 40, and ks→f = 104 as the design variables. For the three multi-objective functions investigated, one can extrapolate the optimum from the Pareto front via the utopia criterion, obtaining h¯ = 502 W/m2 K and Δp = 80 Pa, NuH,unif¯ = 2790 and f = 42, ⟨Ts*⟩s¯= 0.011, and Δp* = 91. The optimal solutions provide original insights and guidelines for the thermal design of graded foam-filled channels.

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“…Another effective way to increase the surface area of a structure is to use the metal foam heat sinks [5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

“…Reducing porosity increases the heat transfer in the wax. Special effect can also be achieved by using the metal foam with graded porosity or finned-metal foam heat sinks [5,39,40], by increasing the porosity towards the source, the performance of the heat sink can be increased [5].…”

Section: Introductionmentioning

confidence: 99%

Influence of the Fin Shape on Heat Transport in Phase Change Material Heat Sink with Constant Heat Loads

2021

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Nowadays, the heat transfer enhancement in electronic cabinets with heat-generating elements can be achieved using the phase change materials and finned heat sink. The latter allows to improve the energy transference surface and to augment the cooling effects for the heat sources. The present research deals with numerical analysis of phase change material behavior in an electronic cabinet with an energy-generating element. For an intensification of heat removal, the complex finned heat sink with overall width of 10 cm was introduced, having the complicated shape of the fins with width of 0.33 cm and height H = 5 cm. The fatty acid with melting temperature of 46 °C was considered as a phase change material. The considered two-dimensional challenge was formulated employing the non-primitive variables and solved using the finite difference method. Impacts of the volumetric heat flux of heat-generating element and sizes of the fins on phase change material circulation and energy transference within the chamber were studied. It was shown that the presence of transverse ribs makes it possible to accelerate the melting process and reduce the source temperature by more than 12 °С at a heat load of 1600 W/m. It should also be noted that the nature of melting depends on the hydrodynamics of the melt, so the horizontal partitions reduce the intensity of convective heat transfer between the upper part of the region and the lower part.

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The effects of variable porosity and cell size on the thermal performance of functionally-graded foams

Cited by 55 publications

References 41 publications

Heat Transfer Augmentation through Different Jet Impingement Techniques: A State-of-the-Art Review

Heat Transfer Augmentation through Different Jet Impingement Techniques: A State-of-the-Art Review

Mono- and Multi-Objective CFD Optimization of Graded Foam-Filled Channels

Influence of the Fin Shape on Heat Transport in Phase Change Material Heat Sink with Constant Heat Loads

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