Some thermophysical properties of paraffin wax as a thermal storage medium

Haji‐Sheikh, A.; Eftekhar, J.; Lou, D. Y. S.

doi:10.2514/6.1982-846

Cited by 11 publications

(5 citation statements)

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“…It is likely that the liquid trapped within the deposit may produce convective effects, which would yield a higher value of the apparent thermal conductivity. The predicted thermal conductivity values in Table are in agreement with the values for wax deposits reported in the literature. ,, …”

Section: Results and Discussion: Mass Of The Deposit Layersupporting

confidence: 88%

Solids Deposition from Multicomponent Wax−Solvent Mixtures in a Benchscale Flow-Loop Apparatus with Heat Transfer

2005

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The deposition of solids from mixtures of a paraffinic wax (C20−C40) dissolved in a multicomponent solvent (C9−C16) was studied under laminar flow conditions. A novel benchscale flow loop was developed, which consisted of a jacketed heat-exchange section for solids deposition on the inner surface of an aluminum tube. Experiments were performed to investigate the effects of the wax−solvent mixture composition, hot and cold stream temperatures, flow or shear rate, deposition residence time, and hydrodynamic entry length on the deposition process. The data were analyzed with a pseudo-steady-state heat-transfer model, which validated the solids deposition process to be controlled primarily by heat transfer. The mass of deposited solids was related to the ratio of temperature difference across the deposit layer and the overall temperature difference. Gas chromatography (GC) analyses of the deposited layer showed significant shifts in the carbon number distribution. The C20+ content of the deposit layer was observed to be higher, by ∼70%−200%, than that of the corresponding wax−solvent mixture.

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Section: Results and Discussion: Mass Of The Deposit Layersupporting

confidence: 88%

Solids Deposition from Multicomponent Wax−Solvent Mixtures in a Benchscale Flow-Loop Apparatus with Heat Transfer

2005

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“…The steady-state value for δz ss can be obtained from Equation (23), by substituting the solution of r ss estimated from Equation ( 21) when R ss = R(0). The proportion of excess liquid δz ss in the steady state is then given by:…”

Section: Steady-state Regimementioning

confidence: 99%

“…Figure 2 shows the behaviour in the steady-state regime of r ss and R ss /R(0) for increasing values of k . The thermodynamic properties of the PCM that belong to paraffin wax are shown in Table 1 [23]. The internal radius of the cylindrical unit is r 0 = 0.00635 m. The initial values of the region delimited by the liquid-solid interface and outer radius are r(0) = 0.01 m and R(0) = 0.108 m, respectively.…”

Section: Numerical Examplesmentioning

confidence: 99%

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Thermophysical Characterization of Paraffin Wax Based on Mass-Accommodation Methods Applied to a Cylindrical Thermal Energy-Storage Unit

2022

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Two mass-accommodation methods are proposed to describe the melting of paraffin wax used as a phase-change material in a centrally heated annular region. The two methods are presented as models where volume changes produced during the phase transition are incorporated through total mass conservation. The mass of the phase-change material is imposed as a constant, which brings an additional equation of motion. Volume changes in a cylindrical unit are pictured in two different ways. On the one hand, volume changes in the radial direction are proposed through an equation of motion where the outer radius of the cylindrical unit is promoted as a dynamical variable of motion. On the other hand, volume changes along the axial symmetry axis of the cylindrical unit are proposed through an equation of motion, where the excess volume of liquid constitutes the dynamical variable. The energy–mass balance at the liquid–solid interface is obtained according to each method of conceiving volume changes. The resulting energy–mass balance at the interface constitutes an equation of motion for the radius of the region delimited by the liquid–solid interface. Subtle differences are found between the equations of motion for the interface. The differences are consistent with mass conservation and local mass balance at the interface. Stationary states for volume changes and the radius of the region delimited by the liquid–solid interface are obtained for each mass-accommodation method. We show that the relationship between these steady states is proportional to the relationship between liquid and solid densities when the system is close to the high melting regime. Experimental tests are performed in a vertical annular region occupied by a paraffin wax. The boundary conditions used in the experimental tests produce a thin liquid layer during a melting process. The experimental results are used to characterize the phase-change material through the proposed models in this work. Finally, the thermodynamic properties of the paraffin wax are estimated by minimizing the quadratic error between the temperature readings within the phase-change material and the temperature field predicted by the proposed model.

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“…With AT = 80 -47 = 33OC, w = 5 mm, 0 = 1.1 x 10W3 K-' (see [9]), and the material properties from Table I,…”

Section: A Simplified Modelmentioning

confidence: 99%

Optimization of a phase change heat sink for extreme environments

Leland

Recktenwald

Ninteenth Annual IEEE Semiconductor Thermal Measurement and Management Symposium, 2003.

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Results of numerical optimization are reported for a phase change heat sink used to cool electronic equipment in extreme environments. The heat sink consists of a conventional, extruded aluminum sink embedded in a block of phase change material. This type of heat sinkis used ininfraredcamerascaniedby fire fighters into burning buildings.Optimization of the geometry of the heat sink assembly involves determination of the fin length, the fin thichess, and the base thickness that maximizes the time time before the base of the heat sink reaches a critical temperature. The numerical model is briefly described, and representative results of the simulation are presented. The optimum design for a given combination of heat load, conductance to ambient, and phase change material is discussed. The model can easily be applied to other geometries, heat loads, and material properties.

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Some thermophysical properties of paraffin wax as a thermal storage medium

Cited by 11 publications

References 1 publication

Solids Deposition from Multicomponent Wax−Solvent Mixtures in a Benchscale Flow-Loop Apparatus with Heat Transfer

Solids Deposition from Multicomponent Wax−Solvent Mixtures in a Benchscale Flow-Loop Apparatus with Heat Transfer

Thermophysical Characterization of Paraffin Wax Based on Mass-Accommodation Methods Applied to a Cylindrical Thermal Energy-Storage Unit

Optimization of a phase change heat sink for extreme environments

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