Empirical equation to estimate viscosity of paraffin

Ferrer, Gerard; Gschwander, Stefan; Solé, Aran; Barreneche, Camila; Fernández, A. Inés; Schossig, Peter

doi:10.1016/j.est.2017.03.002

Cited by 19 publications

(10 citation statements)

References 13 publications

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“…Viscosity results measured for distilled water showed average deviations lower than 1.9% with previous literature[40]. A good agreement was also found between the value of 3.32 mPa•s determined in this work at 303.15 K for bulk-RT21HC and the previous data of 3.16 mPa•s reported at the same temperature for bulk-RT21 (another commercial paraffinic PCM with similar melting point) by Ferrer et al[41]. Shear Viscosity-Shear Rate Flow CurvesFigure 2shows the shear viscosity dependence on shear rate obtained at 278.15 and 303.15 K for water, bulk-RT21HC and four nano-emulsions.…”

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confidence: 91%

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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confidence: 91%

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

et al. 2019

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“…In addition, these results are tied to an analogous study conducted by the authors [28] corrective parameter, as the influence that the carboxylic group has in the melting temperature is different and more important than the carbon atoms difference in paraffin chains. This accordance to study [31] corroborates the suitability of the equation found in this study and indicates that polynomial 3 models are useful equations to predict viscosity of organic PCM.…”

Section: Viscositysupporting

confidence: 89%

Empirical equations for viscosity and specific heat capacity determination of fatty acids

Ferrer

Barreneche

Palacios

et al. 2017

Journal of Energy Storage

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Phase change materials (PCM) used in thermal energy storage (TES) systems have been presented, over recent years, as one of the most effective options in energy storage. Saturated fatty acids are one of the most used PCM in TES systems, as they have high phase change enthalpy but in addition they do not present subcooling nor hysteresis and have proper cycling stability. The simulations and design of a TES system require the knowledge of the thermophysical properties of materials. Thermal conductivity, viscosity, specific heat capacity (C p) can be experimentally determined, but these are material and time consuming tasks. To avoid or to reduce them, and to have reliable data without the need of experimentation, thermal properties can be determined by empirical equations. In this paper, three empirical equations are given to calculate the viscosity, solid C p , and liquid C p of the whole fatty acid family of PCM.

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“…Previous studies measured the viscosity of some of these PCMs at lower temperatures, and Ferrer et al 41 even derived an empirical equation to calculate the viscosity of organic PCM (Equation () and Equation ()):

μ ((), T) ([], italicPa \cdot s) = ((), - 3.66 \times 10^{- 8} \cdot T^{3} + 6.14 \times 10^{- 6} \cdot T^{2} - 4.35 \times 10^{- 4} \cdot T + 1.41 \times 10^{- 2}) \cdot c

c = 0.001 \cdot T_{m}^{2} - 0.0215 \cdot T_{m} + 0.5815

…”

Section: Resultsmentioning

confidence: 99%

Characterisation of commercial phase change materials with potential application in gypsum boards for buildings

Marín

Ushak

Gracia

et al. 2021

Intl J of Energy Research

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Summary Currently, there is an expanded utilisation of lightweight construction structures in buildings, which results in a low structure's thermal storage capacity of the envelope due to the application of thermally unsuitable materials. PCMs incorporated into building structures components are potential alternatives to manage the inadequate thermal energy storage capacity of lightweight structures. To provide a guide for selecting and applying commercial PCMs in construction, nine organic and inorganic bulk materials were selected, and their thermophysical properties were characterised. Thus, the enthalpy of melting/crystallisation, the melting/crystallisation temperature, the stability of 50 cycles, and the verification of the presence of the subcooling phenomenon by DSC and the T‐history method were evaluated. Since the adequate methods to incorporate the PCMs in gypsum are suspension and vacuum impregnation, their thermal properties, together with density and viscosity, need to be considered, properties that are not typically reported in the datasheets of commercial PCMs. Furthermore, the temperature dependence of the viscosity and density of the solid/liquid PCMs were measured by a rheometer and densimeter/pycnometer, respectively. Based on liquid and solid density values, the volumetric expansion of PCMs during the melting process was calculated. Finally, the characterisation parameters were compared with those provided by the suppliers of the different companies. The characterisation's results indicate that for both organic and inorganic PCMs, the fusion temperature (21°C‐26°C) and the density values (0.777‐1.515 g/cm3 for liquid state and 0.895‐1.860 g/cm3 for solid state) were consistent with the values provided in the datasheet from the suppliers'. Viscosity values were found to be higher than expected, and the enthalpy was found to be lower (19%‐30%) when compared with the technical datasheets from manufacturers'. The cycling stability study results were consistent only for the organic samples, without displaying phase segregation or subcooling problems. Based on the thermophysical characterisation, it was possible to establish that three organic RT‐21, RT‐21(TA), RT‐25, and three inorganic SP‐21E, PCM 21C, HS‐24P PCMs would be suitable products for their inclusion into gypsum boards under the conditions analysed. These findings provide new insights regarding the applicability and development of new strategies and materials for passive or active heating/cooling applications in buildings.

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Empirical equation to estimate viscosity of paraffin

Abstract: Està subjecte a una llicència de Reconeixement-NoComercial-SenseObraDerivada 4.0 de Creative Commons

Cited by 19 publications

References 13 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

Empirical equations for viscosity and specific heat capacity determination of fatty acids

Characterisation of commercial phase change materials with potential application in gypsum boards for buildings

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