Experimental Investigation of Solid-Liquid Phase Change in Cylindrical Geometry

2007 ◽  
Author(s):  
L. Katsman ◽  
V. Dubovsky ◽  
G. Ziskind ◽  
R. Letan
Keyword(s):  
Melting Point ◽  
Phase Change ◽  
Digital Camera ◽  
Melting Process ◽  
Cylindrical Geometry ◽  
Water Bath ◽  
Free Expansion ◽  
Dimensionless Groups ◽  
Different Diameters ◽  
Solid Liquid

The present study explores experimentally the process of melting of a phase change material (PCM) in cylindrical geometry. The study is performed with a commercially available paraffin-type material with the melting point of about 28 degrees Celsius. The experiments are conducted using vertical tubes of four different diameters, filled with the PCM and immersed in a water bath. In each tube the experiments are performed at the water bath temperatures of 10, 20 and 30°C above the melting point of the paraffin. The tubes are transparent, and the melting process is monitored and recorded by a digital camera. Each tube is thermally insulated at the bottom, and at its top open to atmosphere, to allow free expansion of the melt liquid. The digital pictures of the melting process were analyzed, and the results were graphically presented as melt fraction vs. time, showing for the plain tubes the effects of tube diameter and temperature difference. Numerical simulations are performed in order to provide an insight into the mechanisms governing the process. Generalization of the results is attempted based on the dimensionless groups, including the Fourier, Stefan, and Rayleigh numbers. A correlation connecting the melt fraction with these dimensionless groups is suggested.

Experimental Investigation of Melting in Vertical Circular Tubes

2008 ◽  
Author(s):  
L. Fraiman ◽  
E. Benisti ◽  
G. Ziskind ◽  
R. Letan
Keyword(s):  
Melting Point ◽  
Digital Camera ◽  
Melting Process ◽  
Water Bath ◽  
Free Expansion ◽  
Circular Tubes ◽  
Dimensionless Groups ◽  
Different Diameters ◽  
Vertical Tubes ◽  
Rayleigh Numbers

The present study explores experimentally the process of melting of a phase change material (PCM) in vertical circular tubes. The study is performed with a commercially available paraffin-type material with the melting point of about 28 degrees Celsius. The experiments are conducted using vertical tubes of four different diameters, filled with the PCM and immersed in a water bath. In each tube the experiments are performed at the water bath temperatures of 10, 20 and 30°C above the melting point of the paraffin. Three different initial heights of the PCM inside the tubes are considered, thus bringing the total number of cases explored to thirty six. Each tube is thermally insulated at the bottom, and at its top open to atmosphere, to allow free expansion of the melt liquid. The tubes are transparent, and the melting process is monitored and recorded by a digital camera. The digital pictures of the melting process are analyzed, and the results are graphically presented as melt fraction vs. time, showing the effects of tube diameter, PCM height and temperature difference. Generalization of the results is attempted based on the dimensionless groups, including the Fourier, Stefan, and Rayleigh numbers. A correlation connecting the melt fraction with these dimensionless groups is suggested.

The Lattice Boltzmann Investigation for the Melting Process of Phase Change Material in an Inclined Cavity

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Zhonghao Rao ◽  
Yutao Huo ◽  
Yimin Li
Keyword(s):  
Heat Flux ◽  
Phase Change ◽  
Lattice Boltzmann ◽  
Melting Process ◽  
Clockwise Rotation ◽  
Linear Distribution ◽  
Left Wall ◽  
Inclined Cavity ◽  
Solid Liquid ◽  
Change Material

The solid–liquid phase change process is of importance in the usage of phase change material (PCM). In this paper, the phase change lattice Boltzmann (LB) model has been used to investigate the solid–liquid phase change in an inclined cavity. Three heat flux distributions applied to the left wall are investigated: uniform distribution, linear distribution, and parabolic symmetry distribution. The results show that for all the heat flux distributions, the slight clockwise rotation of the cavity can accelerate the melting process. Furthermore, when more heat is transferred to the cavity through the middle part (parabolic symmetry distribution) or bottom part (linear distribution) of left wall, clockwise rotation of cavity leads to larger temperature of PCM.

Numerical Simulation of Thermal Energy Storage in Cylindrical Cells

2002 ◽  
Author(s):  
Horacio Ramos-Aboites ◽  
Abel Hernandez-Guerrero ◽  
Salvador M. Aceves ◽  
Raul Lesso-Arroyo
Keyword(s):  
Energy Storage ◽  
Phase Change ◽  
Fluid Flows ◽  
Melting Process ◽  
Inlet Temperature ◽  
Transient Model ◽  
Storage Cell ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Change Material

This paper presents the results of a -numerical transient model for phase change in a storage cell filled with a phase change material (PCM). Phase change occurs under the presence of natural convection. The PCM is encapsulated in a cylindrical energy storage cell. Two cases of PCM melting are analyzed, (1) the surface temperature of the bottom half of the cylindrical cell is kept at a constant temperature, which is higher than the melting temperature of the PCM, and (2) a fluid flows under the cell with an inlet temperature that is higher than the melting point of the PCM. The results show the evolution of the solid-liquid interface, isotherms and flow lines during the melting process.

Thermodynamic Optimization of Phase-Change Energy Storage Using Two or More Materials

1992 ◽  
Vol 114 (1) ◽  
pp. 84-90 ◽  
Author(s):  
J. S. Lim ◽  
A. Bejan ◽  
J. H. Kim
Keyword(s):  
Energy Storage ◽  
Melting Point ◽  
Phase Change ◽  
Phase Change Material ◽  
Finite Thickness ◽  
Melting Process ◽  
Two Phase ◽  
In Series ◽  
Optimal Melting ◽  
Change Material

This paper documents the relative merits of using more than one type of phase-change material for energy storage. In the case of two phase-change systems in series, which are melted by the same stream of hot fluid, there exists an optimal melting point for each of the two materials. The first (upstream) system has the higher of the two melting points. The second part of the paper addresses the theoretical limit in which the melting point can vary continuously along the source stream, i.e., when an infinite number of different (and small) phase-change systems are being heated in series. It is shown that the performance of this scheme is equivalent to that which uses an optimum single phase-change material, in which the hot stream remains unmixed during the melting process. The time dependence, finite thickness and longitudinal variation of the melt layer caused by an unmixed stream are considered in the third part of the paper. It is shown that these features have a negligible effect on the optimal melting temperature, which is slightly higher than (T∞Te)1/2.

scholarly journals Numerical investigation on the phase change process of different shaped macro encapsulated PCM

2018 ◽  
Vol 7 (4.5) ◽  
pp. 587
Author(s):  
Jay R. Patel ◽  
Manish K. Rathod
Keyword(s):  
Energy Storage ◽  
Phase Change ◽  
Phase Change Material ◽  
Melting Process ◽  
Complex Flow ◽  
Ansys Fluent ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Convection Dominated ◽  
Change Material

Latent heat energy storage using macro encapsulated phase change material is an emerging technique for thermal energy storage applica- tions. The main aim of the present investigation is to investigate the melting process of phase change material filled in different shaped configurations. The selected different cavities are square, circular and triangular. A mathematical model based on convection dominated melting is required to be developed, especially in view of the complex flow geometries encountered in such problems. Thus, an attempt has been made to develop a model using ANSYS Fluent 16.2 to investigate the heat transfer rate and solid-liquid interface visualization of PCM filled in different shapes of cavity. It is found that triangular shaped macro encapsulated PCM melts faster than square and circu- lar shaped encapsulated PCM.   

scholarly journals Numerical Investigations on Melting Behavior of Phase Change Material in a Rectangular Cavity at Different Inclination Angles

2018 ◽  
Vol 8 (9) ◽  
pp. 1627 ◽  
Author(s):  
Yong Wang ◽  
Jingmin Dai ◽  
Dongyang An
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Melting Process ◽  
Melting Behavior ◽  
Rectangular Cavity ◽  
Melting Time ◽  
Inclination Angles ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Change Material

This paper investigates the melting process of phase change material in a rectangular cavity at different inclination angles. Paraffin is used as a phase change material in this study. One side of the cavity is heated while the other sides are considered to be adiabatic. The investigated angles of inclination include 0° (bottom horizontal heating), 30°, 60°, 90° (vertical heating), 120°, 150° and 180° (top horizontal heating). Shapes of the solid liquid interface and temperature variations during the melting process were discussed for all the inclination angles. The results reveal that the inclination angles have a significant impact on the melting behavior of paraffin. As the angle increases from 0° to 180°, the complete melting time increases non-linearly.

An Analytical and Experimental Model for a Thermosyphon That Employs Solid/Liquid Phase Change Materials

2000 ◽  
Author(s):  
A. G. Agwu Nnanna ◽  
Kendall T. Harris ◽  
A. Haji-Sheikh
Keyword(s):  
Heat Transfer ◽  
Liquid Phase ◽  
Phase Change ◽  
Analytical Method ◽  
Practical Importance ◽  
Melting Process ◽  
Passive Cooling ◽  
Efficient Design ◽  
Quick Method ◽  
Solid Liquid

Abstract Application of solid/liquid phase change material (PCM) for passive cooling of electronic modules is on the increase. A simplified method of predicting the thermal performance of passive cooling systems is needed for efficient design of thermal storage systems. This paper presents an experimental and approximate analytical method for quick estimation of the rate of thermal transport in solid/liquid PCM during and after the melting process. However, the emphasis of this paper is on the transport phenomena after the melting process is completed. This research is motivated in part by the need for a simplified analytical method of predicting the rate of heat transfer in buoyancy-driven fluids within a partitioned enclosure, and the need for a fundamental understanding of the rate of heat transfer in liquid melt after the phase change phenomena. These needs are of practical importance for efficient design of a thermal energy storage system. The approximate analytical model serves as a quick method of studying the performance of a thermosyphon system.

Inward Melting in a Vertical Tube Which Allows Free Expansion of the Phase-Change Medium

1982 ◽  
Vol 104 (2) ◽  
pp. 309-315 ◽  
Author(s):  
E. M. Sparrow ◽  
J. A. Broadbent
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Numerical Solutions ◽  
Melting Process ◽  
Vertical Tube ◽  
Conduction Model ◽  
Free Expansion ◽  
Melting Front ◽  
Quantitative Results ◽  
Change Temperature

Experiments on the melting of a phase-change medium in a vertical tube yielded quantitative results both for the heat transfer and the timewise evolution of the melting front. The upper surface of the phase-change medium was bounded by an insulated air space, which accommodated the volume changes which accompany the melting process. Numerical solutions based on a pure conduction model were also performed for comparison purposes. It was found that the rate of melting and the heat transfer are significantly affected by fluid motions in the liquid melt induced by the volume change and by natural convection, with the former being significant only at early times. For melting initiated with the solid at the phase-change temperature, the experimentally determined values of the energy transfer associated with the melting process were about 50 percent higher than those predicted by the conduction model. Furthermore, the measured values of the energy stored in the liquid melt were about twice the conduction prediction. A compact dimensionless correlation of the experimental results was achieved using the Fourier, Stefan, and Grashof numbers. Initial subcooling of the solid substantially decreased the rate of melting, with corresponding decreases in the energy transfers for melting and sensible heat storage.

scholarly journals Numerical Study on Melting Heat Transfer in Dendritic Heat Exchangers

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2504 ◽  
Author(s):  
Xinmei Luo ◽  
Shengming Liao
Keyword(s):  
Heat Exchanger ◽  
Liquid Phase ◽  
Phase Change ◽  
Heat Exchangers ◽  
Numerical Study ◽  
Phase Interface ◽  
Dendritic Structure ◽  
Melting Process ◽  
High Efficient ◽  
Solid Liquid

The dendritic fin was introduced to improve the solid-liquid phase change in heat exchangers. A theoretical model of melting phase change in dendritic heat exchangers was developed and numerically simulated. The solid-liquid phase interface, liquid phase rate and dynamic temperature change in dendritic heat exchanger during melting process are investigated and compared with radial-fin heat exchanger. The results indicate that the dendritic fin is able to enhance the solid-liquid phase change in heat exchanger for latent thermal storage. The presence of dendritic fin leads to the formation of multiple independent PCM zones, so the heat can be quickly diffused from one point to across the surface along the metal fins, thereby making the PCM far away from heat sources melt earlier and faster. In addition, the dendritic structure makes the PCM temperature distribution more uniform over the entire zone inside heat exchangers due to high-efficient heat flow distribution of dendritic fins. As a result, the time required for the complete melting of the PCM in dendritic heat exchanger is shorter than that of the radial-fin heat exchanger.

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