Experimental research of viscosity of microencapsulated PCM slurry at the phase change temperature

Dutkowski, Krzysztof; Fiuk, Jacek Jan

doi:10.1016/j.ijheatmasstransfer.2019.02.036

Cited by 39 publications

(23 citation statements)

References 30 publications

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“…In fact, a volumetric study of this nano-emulsion system [32] showed as density of RT21HC(10 wt.%)/Water sample reduced by 1.1% when heated from 292 to 296 K, while pure water only exhibited a density reduction of 0.1% in the same temperature range. Another plausible explanation was recently proposed by Dutkowski and Fiuk [20,21] when the studied Micronal®DS 2039 X, an aqueous slurry containing paraffin micro-capsules coated with a highly cross-linked polymethyl methacrylate. Authors attributed similar deformations in heating µ(T) curves around phase change to the chaotic movement of the non-molten core inside partially melted micro-capsules.…”

Section: Shear Viscosity-temperature Sweepsmentioning

confidence: 82%

“…Such deformations in µ(T) curves were attributed to changes in the shape or volume of PCM droplets undergoing solid-liquid phase transition or to the creation to transient networks among neighboring droplets. In the case of micro-encapsulated paraffin slurries, Dutkowski and Fiuk [20] recently ascribed similar alterations in heating µ(T) sweeps to the chaotic movement of the non-molten core inside partially melted micro-capsules. Hence, non-uniformity in the solid/liquid state of paraffin droplets may increase internal friction resistance between carrier fluid layers.…”

Section: Introductionmentioning

confidence: 86%

“…The friction caused by relative movements between layers of dispersed material makes that the moment of rotation transmitted to the surface layers gets reduced as it moves towards the center of the drops. This internal circulation in liquid particles reduces resulting droplet rotation and, consequently, flow disturbance [20]. The higher the dispersed phase to continuous phase viscosity ratio (i.e., z = µ PCM /µ water ), the more deformed will get the streamlines (approaching the limit of droplet viscosity of rigid-sphere suspensions).…”

Section: Surface Propertiesmentioning

confidence: 99%

“…Some rheological studies on PCM nano-emulsions [4,5,9,13,[15][16][17] or suspensions containing micro-encapsulated PCMs [18][19][20][21] also analyzed changes in dynamic viscosity occurring during the solidifyication/melting of phase change material droplets/micro-capsules. Most of those investigations observed deformations in shear viscosity-temperature evolution at temperatures around solid-liquid transitions.…”

Section: Introductionmentioning

confidence: 99%

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Dynamic Viscosity, Surface Tension and Wetting Behavior Studies of Paraffin–in–Water Nano–Emulsions

et al. 2019

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This work analyzes the dynamic viscosity, surface tension and wetting behavior of phase change material nano–emulsions (PCMEs) formulated at dispersed phase concentrations of 2, 4 and 10 wt.%. Paraffin–in–water samples were produced using a solvent–assisted route, starting from RT21HC technical grade paraffin with a nominal melting point at ~293–294 K. In order to evaluate the possible effect of paraffinic nucleating agents on those three properties, a nano–emulsion with 3.6% of RT21HC and 0.4% of RT55 (a paraffin wax with melting temperature at ~328 K) was also investigated. Dynamic viscosity strongly rose with increasing dispersed phase concentration, showing a maximum increase of 151% for the sample containing 10 wt.% of paraffin at 278 K. For that same nano–emulsion, a melting temperature of ~292.4 K and a recrystallization temperature of ~283.7 K (which agree with previous calorimetric results of that emulsion) were determined from rheological temperature sweeps. Nano–emulsions exhibited surface tensions considerably lower than those of water. Nevertheless, at some concentrations and temperatures, PCME values are slightly higher than surface tensions obtained for the corresponding water+SDS mixtures used to produce the nano–emulsions. This may be attributed to the fact that a portion of the surfactant is taking part of the interface between dispersed and continuous phase. Finally, although RT21HC–emulsions exhibited contact angles considerably inferior than those of distilled water, PCME sessile droplets did not rapidly spread as it happened for water+SDS with similar surfactant contents or for bulk–RT21HC.

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Section: Shear Viscosity-temperature Sweepsmentioning

confidence: 82%

Section: Introductionmentioning

confidence: 86%

Section: Surface Propertiesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Dynamic Viscosity, Surface Tension and Wetting Behavior Studies of Paraffin–in–Water Nano–Emulsions

et al. 2019

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“…2 To alleviate the problem, many studies were conducted, including adding conductive nanoparticles, [3][4][5][6] adopting fins, [7][8][9][10] porous materials/ foams, [11][12][13][14] microcapsules, 15,16 and multiple PCMs. 17 Farid 18,19 suggested the use of a range of different PCMs, with different melting points, to obtain phase change heat storage units. Numerical simulation and experimental data indicate that both charge and discharge rates can be improved by using thoroughly selected multiple PCMs.…”

mentioning

confidence: 99%

Experimental and numerical investigation of the melting process and heat transfer characteristics of multiple phase change materials

Wang

et al. 2020

Int J Energy Res

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The melting and heat transfer characteristics of multiple phase change materials (PCMs) are investigated both experimentally and numerically. Multiple PCMs, which consist of three PCMs with different melting points, are filled into a rectangle-shaped cavity to serve as heat storage unit. One side of the cavity is set as heating wall. The melting rate of multiple PCMs was recorded experimentally and compared with that of single PCM for different heating temperatures. A two-dimensional mathematical model to describe the phase change heat transfer was developed and verified experimentally. The properties of multiple PCMs, including the effect of the melting point difference (combined type), thermal conductivity, and latent heat, on the heat transfer performance of the PCM were analyzed numerically. The results show that, the melting time decreases before it increases, with an increasing melting point difference for the multiple PCMs. In addition, the melting point decreases with increasing distance from the heating wall. Most of these types of multiple PCMs melt faster than the single PCM, and the multiple PCMs, with the melting point arranged as 322 K/313 K/304 K, has the shortest melting time in this study. The melting rate of the multiple PCMs, 322 K/313 K/304 K, accelerates faster than for the single PCM as the thermal conductivity, latent heat, and heating wall temperature increase. Finally, generalized results are obtained using a dimensionless analysis for both single and multiple PCMs.

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Research progress on preparation, characterization, and application of nanoparticle‐based microencapsulated phase change materials

Lin

Zhang

et al. 2021

Int J Energy Res

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Summary As an energy storage material, microencapsulated phase change materials (MPCMs) have become a research hotspot in recent years due to their unique thermophysical properties. However, this material usually has limitations in terms of its performance, such as low encapsulation efficiency, leakage during phase change, poor cycle stability, and high degree of supercooling. To solve these problems, nanoparticle as‐modified material to improve the performance of MPCMs has attracted the attention of both domestic and overseas scholars. This paper aims to review the research progress of MPCMs modified by nanoparticle from three aspects: preparation, performance, and application. In this paper, the preparation method and principle of nanoparticles used for the modification of MPCMs are first introduced. Then, based on different properties (mechanical properties, thermal conductivity, thermal stability, and supercooling), the research works of nanoparticle‐modified MPCMs in recent years are reviewed. Finally, the practical applications of nanocomposite MPCM in the field of slurry, building, asphalt pavement, and battery thermal management are reported.

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Experimental research of viscosity of microencapsulated PCM slurry at the phase change temperature

Cited by 39 publications

References 30 publications

Dynamic Viscosity, Surface Tension and Wetting Behavior Studies of Paraffin–in–Water Nano–Emulsions

Dynamic Viscosity, Surface Tension and Wetting Behavior Studies of Paraffin–in–Water Nano–Emulsions

Experimental and numerical investigation of the melting process and heat transfer characteristics of multiple phase change materials

Research progress on preparation, characterization, and application of nanoparticle‐based microencapsulated phase change materials

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