Thermal energy storage in a confined cylindrical heat source filled with phase change materials

Sharma, Aakriti; Trivedi, Mohit; Agarwal, Kalyani; Nirmalkar, Neelkanth

doi:10.1016/j.ijheatmasstransfer.2021.121603

Cited by 10 publications

(7 citation statements)

References 35 publications

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“…min, blue after 6 min, red after 10 min and green after 17 min. Comparing simulations by Brent et al[36] (solid line), Tiari et al[42] (finely dotted), and Sharma et al[43] (dashed) and experiments by Gau and Viskanta[35] (circles) with our simulation results (large dots).Evidently, this creates a shape of the curve that does not agree well with the experiments. One finds a backwards curved front near the top boundary that is not observed in the experiments.…”

contrasting

confidence: 47%

“…No such information is provided in the experimental work of Gau and Viskanta [35], and details provided about the simulation results of Saldi [33] and Brent et al [36] are scarce. Tiari et al [42] and Sharma et al [43] do not provide any deeper insight into the velocity and temperature fields. The flow field at the beginning is characterized by a narrow vertical column of fluid between the hot left wall and the comparably cold melting front, which is advancing evenly towards the right.…”

mentioning

confidence: 98%

“…First, Tiari et al 2021 [42], who use the commercial FVM fluid dynamics code Ansys, with a mesh resolution between 12,500 and 50,000 elements. Secondly, Sharma et al 2021 [43], who use the commercial (Eulerian) FEM code COMSOL. The equations to be solved are clearly described, but no further details about the simulation setup are given in either reference.…”

mentioning

confidence: 99%

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Simulation of the Marangoni Effect and Phase Change Using the Particle Finite Element Method

et al. 2021

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A simulation method is developed herein based on the particle finite element method (PFEM) to simulate processes with surface tension and phase change. These effects are important in the simulation of industrial applications, such as welding and additive manufacturing, where concentrated heat sources melt a portion of the material in a localized fashion. The aim of the study is to use this method to simulate such processes at the meso-scale and thereby gain a better understanding of the physics involved. The advantage of PFEM lies in its Lagrangian description, allowing for automatic tracking of interfaces and free boundaries, as well as its robustness and flexibility in dealing with multiphysics problems. A series of test cases is presented to validate the simulation method for these two effects in combination with temperature-driven convective flows in 2D. The PFEM-based method is shown to handle both purely convective flows and those with the Marangoni effect or melting well. Following exhaustive validation using solutions reported in the literature, the obtained results show that an overall satisfactory simulation of the complex physics is achieved. Further steps to improve the results and move towards the simulation of actual welding and additive manufacturing examples are pointed out.

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confidence: 47%

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confidence: 98%

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Simulation of the Marangoni Effect and Phase Change Using the Particle Finite Element Method

et al. 2021

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“…[2a,b] Within the heat sink, heat transfer is limited to conductive pathways due to the role of PCM confinement between fins effectively eliminating convection, which is valid at low Rayleigh numbers. [13,14] The materials chosen for this study are octadecane. [17] and aluminum alloy AlSi12 which were chosen for their desirable material properties, latent heat and thermal conductivity, respectively, and accessibility of application (Table 1).…”

Section: Problem Statementmentioning

confidence: 99%

“…The use of this approximation has been established as a valid approximation in finned PCM composites in the limit of small length scales (Figure 1a,d) where the associated Rayleigh numbers become relatively small, corresponding to negligible levels of convective heat transfer. [ 13 ] For these conditions, geometric confinement and fluid viscosity dampen the buoyant forces and heat transfer becomes dominated by conduction [5b,9c,14] . Convergence with this approximation is achieved using a critical spacing bifurcation scheme (Figure 1b,c).…”

Section: Introductionmentioning

confidence: 97%

Design of Radially Variant Phase‐Change Material Composites

et al. 2022

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Phase‐change materials (PCMs) and high‐conductivity elements can be combined to form highly compact and efficient composite heat sinks. However, the design challenge presented by thermal composites composed of PCMs and high‐conductivity elements remains unresolved. Herein, design guidelines are presented for radially varying cylindrical PCM composites. Numerical and analytical techniques are utilized to explore the utility and limits of optimal composite designs selecting for 1) temperature minimization, 2) specific effective heat capacity maximization, and 3) volumetric effective heat capacity maximization. Significant increases in each metric are observed when implementing radially variant designs in cylindrical geometries, especially for metrics of heat capacity. Furthermore, a hybrid approach to variant composite design is presented, allowing for the balancing of different design objectives. The utilization of a variable design under high heat flux (10 ± 1.4 W cm−2) and short melting periods (up to 50 s) is experimentally demonstrated, directly resulted in a 65% decrease in total system mass and a 200% increase in specific heat capacity while maintaining strong temperature dampening performance. In a second case study, a 23% decrease in mass is demonstrated while maintaining strong specific heat performance, emphasizing the broad utility of this approach.

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Numerical analysis and optimization of the charging process on a shell‐and‐tube latent heat thermal energy storage unit for a solar power plant with direct steam generation

Deng

Zhu

Wang

et al. 2022

Energy Science & Engineering

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A two-dimensional model of the charging process on a heat storage unit in a shell-and-tube type latent heat subsystem of a solar power plant with direct steam generation was constructed in this study. The effects of the outer diameter to inner diameter ratio, aspect ratio, phase change material (PCM) thermal conductivity, and heat transfer fluid (HTF) mass flow rate were investigated. Results show that increasing the PCM thermal conductivity, HTF mass flow rate, and aspect ratio of the heat storage unit can shorten heat storage time, but the ratio of the outer diameter to the inner diameter of the heat storage unit has an optimal value of 6 in this problem. Using response surface methodology analysis, the influence of the aspect ratio, outer-to-innerdiameter ratio, PCM thermal conductivity, and HTF mass flow rate on the storage time of the phase change heat storage unit is in descending order.After a genetic algorithm optimization, the storage rate of the heat storage unit increased by 35%. The results of this study can guide the heat storage unit to achieve a better practical application performance.

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Thermal energy storage in a confined cylindrical heat source filled with phase change materials

Cited by 10 publications

References 35 publications

Simulation of the Marangoni Effect and Phase Change Using the Particle Finite Element Method

Simulation of the Marangoni Effect and Phase Change Using the Particle Finite Element Method

Design of Radially Variant Phase‐Change Material Composites

Numerical analysis and optimization of the charging process on a shell‐and‐tube latent heat thermal energy storage unit for a solar power plant with direct steam generation

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