Simulations of melting performance enhancement for a PCM embedded in metal periodic structures

Zhao, Chunrong; Opolot, Michael; Liu, Ming; Bruno, Frank; Mancin, Simone; Flewell-Smith, Ross; Hooman, Kamel

doi:10.1016/j.ijheatmasstransfer.2020.120853

Cited by 45 publications

(18 citation statements)

References 34 publications

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“…Flow over and through the porous media is encountered in several natural phenomena and a wide range of industrial applications. Cooling of electronic devices with metal foam heat sinks [1,2], energy storage systems [3,4], heat exchangers [5,6], noise control in the aerospace industry [5,7,8], and flow over vegetation in the canopies in environmental engineering [9][10][11] can be a few examples of typical flow over and through the porous media. Remarkable research has been conducted in literature either experimentally or numerically to explore the flow physics over fluid-saturated porous media.…”

Section: Introductionmentioning

confidence: 99%

Flow leakage and Kelvin–Helmholtz instability of turbulent flow over porous media

et al. 2022

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In the present paper, turbulent flow in a composite porous-fluid system including a permeable surface-mounted bluff body immersed in a turbulent channel flow is investigated using pore-scale large eddy simulation. The effect of Reynolds number (Re) on the flow leakage from porous to non-porous regions, Kelvin-Helmholtz (K-H) instabilities, as well as coherent structures over the porous-fluid interface are elaborated. Results show that more than 52% of the fluid entering the porous blocks leaks from the first half of the porous region to the non-porous region through the porous-fluid interface. As the Re number increases, the flow leakage decreases by 24%. Flow visualization shows that the Re number affects the size of counter-rotating vortex pairs and coherent hairpin structures above the porous block. Moreover, turbulence statistics show that by reducing the Re number, turbulence production is delayed downstream; at the Re=14400, it begins from the leading edge of the porous block (X/D=0), while at the Re=3600, turbulence production is postponed and starts nearly at the middle of the porous block (X/D=4.6). Finally, the distribution of pressure gradient for the three Re numbers confirms the occurrence of the K-H instability vortices over the porous-fluid interface. For Re = 3600, the K-H instability vortices show a linear growth rate in the vertical and horizontal directions with the slope of 0.136 and 0.05, respectively. However, by increasing the Re from 3600 to 14400, the growth rate slop in the horizontal direction decreases by nearly 33.8%, while in the vertical direction, it increases by 201%.

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Section: Introductionmentioning

confidence: 99%

Flow leakage and Kelvin–Helmholtz instability of turbulent flow over porous media

et al. 2022

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“…The missing part in the literature is to identify pertinent parameters and investigate their impacts on the heat transfer performance so that an optimised system can be designed regardless of the enhancer and PCM material properties. Hence, this paper is presented to fill this gap using a previously developed periodic structure model [23] .…”

Section: Critical Cell Sizementioning

confidence: 99%

“…Opolot et al [22] investigated the effects of wall thermal contact resistance for such geometry and offered theoretical and numerical results to evaluate and minimize the thermal contact resistance. Zhao et al [23] numerically studied the effects of pore density of a 0.9 porosity periodic structure on the PCM melting time reduction for different ligament materials (copper, aluminium, nickel, and stainless steel). Two different trends of the melting time curves with respect to PPI, i.e., monotonical decline and parabolic, were reported depending on the material (enhancer) properties.…”

Section: Introductionmentioning

confidence: 99%

Periodic structures for melting enhancement: observation of critical cell size and localized melting

Zhao

Opolot

Liu

et al. 2022

International Journal of Heat and Mass Transfer

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“…They are often based on either play/design with the tune geometry of the device or system for TES usage [12] or to increase the thermal conductivity of the PCM-based composite. The latter can be achieved by using additions and/or high-conducting particles such as carbon microfibers [13,14], fine materials such as copper [15], graphite [16], aluminum [17], bronze [18], nickel and stainless steel [19], graphene nano-platelets [20], and carbon nanotubes [21].…”

Section: Introductionmentioning

confidence: 99%

Multiobjective Optimization of Cement-Based Panels Enhanced with Microencapsulated Phase Change Materials for Building Energy Applications

2022

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Thermal energy storage using phase change materials (PCMs) is a promising technology for improving the thermal performance of buildings and reducing their energy consumption. However, the effectiveness of passive PCMs in buildings depends on their optimal design regarding the building typology and typical climate conditions. Within this context, the present contribution introduces a novel multiobjective computational method to optimize the thermophysical properties of cementitious building panels enhanced with a microencapsulated PCM (MPCM). To achieve this, a parametric model for PCM-based cementitious composites is developed in EnergyPlus, considering as design variables the melting temperature of PCMs and the thickness and thermal conductivity of the panel. A multiobjective genetic algorithm is dynamically coupled with the building energy model to find the best trade-off between annual heating and cooling loads. The optimization results obtained for a case study building in Sofia (Bulgaria-EU) reveal that the annual heating and cooling loads have contradictory performances regarding the thermophysical properties studied. A thick MPCM-enhanced panel with a melting temperature of 22 °C is needed to reduce the heating loads, while a thin panel with a melting temperature of 27 °C is required to mitigate the cooling loads. Using these designs, the annual heating and cooling loads decrease by 23% and 3%, respectively. Moreover, up to 12.4% cooling load reduction is reached if the thermal conductivity of the panels is increased. Therefore, it is also concluded that the thermal conductivity of the cement-based panels can significantly influence the effectiveness of MPCMs in buildings.

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Simulations of melting performance enhancement for a PCM embedded in metal periodic structures

Cited by 45 publications

References 34 publications

Flow leakage and Kelvin–Helmholtz instability of turbulent flow over porous media

Flow leakage and Kelvin–Helmholtz instability of turbulent flow over porous media

Periodic structures for melting enhancement: observation of critical cell size and localized melting

Multiobjective Optimization of Cement-Based Panels Enhanced with Microencapsulated Phase Change Materials for Building Energy Applications

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