Close-Contact Melting Inside an Elliptical Cylinder

2000 ◽  
Vol 122 (4) ◽  
pp. 192-195 ◽  
Author(s):  
Sergei A. Fomin ◽  
Alexander V. Wilchinsky ◽  
Takeo S. Saitoh
Keyword(s):  
Mathematical Model ◽  
Thermal Energy ◽  
Close Contact ◽  
Energy Systems ◽  
Elliptic Cylinder ◽  
Melting Process ◽  
Melting Rate ◽  
Contact Melting ◽  
Approximate Mathematical Model ◽  
Characteristic Scales

An approximate mathematical model of contact melting in a horizontal elliptic cylinder is developed. The main characteristic scales and nondimensional parameters that describe the principal features of the melting process are found. It is shown that melting rate depends on the shape of the capsule. This is especially important for the design of practical latent heat thermal energy systems. [S0199-6231(00)00504-9]

scholarly journals Numerical Investigation on the Evolution of Thin Liquid Layer and Dynamic Behavior of an Electro-Thermal Drilling Probe during Close-Contact Heat Transfer

2021 ◽  
Vol 11 (8) ◽  
pp. 3443
Author(s):  
Chan Ho Jeong ◽  
Kwangu Kang ◽  
Ui-Joon Park ◽  
Hyung Ju Lee ◽  
Hong Seok Kim ◽  
...  
Keyword(s):  
Liquid Layer ◽  
Close Contact ◽  
Melting Process ◽  
Transient Behavior ◽  
Liquid Films ◽  
Melting Rate ◽  
Contact Melting ◽  
Contact Heat ◽  
Navier Stokes Equation ◽  
Thermal Drilling

This study investigates the transient behavior of an electro-thermal drilling probe (ETDP) during a close-contact melting process within a glacier. In particular, the present work analyzes the effect of the tip temperature on the formation of molten thin liquid films and the subsequent rate of penetration (ROP) through numerical simulation. We used the commercial code of ANSYS Fluent (v.17.2) to solve the Reynolds-averaged Navier–Stokes equation, together with an energy equation considering the solidification and melting model. The ROP of the drilling probe is determined based on the energy balance between the heating power and melting rate of ice. As the results, the ETDP penetrates the ice through a close-contact melting process. The molten liquid layer with less than 1 mm of thickness forms near the heated probe tip. In addition, the ROP increases with the heated temperature of the probe tip.

Simulation and Dynamic Characteristics of Discharging Process of Storage Tank Used in Conventional Air-Conditioning

2011 ◽  
Vol 383-390 ◽  
pp. 2974-2977
Author(s):  
Xiao Yan Li ◽  
Yan Yan Wu ◽  
Zhi Fen Cen
Keyword(s):  
Thermal Energy ◽  
Storage Tank ◽  
Dynamic Performance ◽  
Melting Process ◽  
Melting Rate ◽  
Heat Transfer Process ◽  
Inlet Temperature ◽  
Appreciable Change ◽  
Apparent Heat Capacity ◽  
Capacity Method

Mathematical model of heat transfer process of a latent heat thermal storage tank was established, dynamic performance and melting process of cool storage tank were simulated by the apparent heat capacity method. the relation of melting rate along with time and cold thermal energy released along with time were obtained. The results show that no appreciable change in the total cold thermal energy released is observed for the increase of flow rate, whereas improvement on total cold thermal energy released due to the increase of inlet temperature is detectable. At the cool discharge condition, the best inlet temperature of storage tank is at 12°C-13°C.

An Experimental and Analytical Study of Close-Contact Melting

1986 ◽  
Vol 108 (4) ◽  
pp. 894-899 ◽  
Author(s):  
M. K. Moallemi ◽  
B. W. Webb ◽  
R. Viskanta
Keyword(s):  
Approximate Solution ◽  
Surface Temperature ◽  
Cross Section ◽  
Analytical Study ◽  
Close Contact ◽  
Rectangular Cross Section ◽  
Melting Rate ◽  
Contact Melting ◽  
Series Of Experiments ◽  
Convection Dominated

Close-contact melting was investigated by performing a series of experiments in which blocks of solid n-octadecane (with circular or rectangular cross section) were melted by a horizontal planar heat source at constant surface temperature. Close contact between the source and the solid prevailed throughout the experiments by permitting the uncontained solid to descend under its own weight while squeezing the melt out of the gap separating it from the source. The velocity of the solid was measured and is reported as a function of the instantaneous weight of the solid. Effects of the surface temperature of the source and radius of the solid on its temporal velocity are also reported. A closed-form approximate solution is developed for the motion of solid and predictions are compared with the experimental data. The results for the solid velocity are correlated in terms of the governing parameters of the problem as revealed by the approximate solution. Compared with natural convection-dominated melting from below (solid confined and contained in a rectangular cavity) close contact gives rise to approximately a sevenfold increase in the melting rate of the solid.

Close-contact melting on an isothermal surface with the inclusion of non-Newtonian effects

2019 ◽  
Vol 865 ◽  
pp. 720-742 ◽  
Author(s):  
Y. Kozak ◽  
Yi Zeng ◽  
Rabih M. Al Ghossein ◽  
J. M. Khodadadi ◽  
G. Ziskind
Keyword(s):  
Yield Stress ◽  
Layer Thickness ◽  
Close Contact ◽  
Melting Rate ◽  
Analytical Approximation ◽  
Contact Melting ◽  
Viscoplastic Fluid ◽  
Molten Layer ◽  
Isothermal Surface ◽  
Dimensionless Groups

The present study deals with a theoretical investigation of a close-contact melting (CCM) process involving a vertical cylinder on a horizontal isothermal surface, where the liquid phase is a non-Newtonian viscoplastic fluid that behaves according to the Bingham model. Accordingly, a new approach is formulated based on the thin layer approximation and different quasi-steady process assumptions. By analytical derivation, an algebraic equation that relates the molten layer thickness and the solid bulk height is developed. The problem is then solved numerically, coupled with another equation for the melting rate. The new model shows that as the yield stress increases the melting rate decreases and the molten layer thickness increases. It is found that under certain conditions, the model can be reduced to a form that allows an analytical solution. The approximate model predicts an exponential dependence of both the melt fraction and the molten layer thickness. Comparison between the numerical and analytical solutions shows that the analytical approximation provides an excellent estimation for sufficiently large values of the yield stress. Dimensional analysis, which is supported by the analytical model results, reveals the dimensionless groups that govern the problem. For the general case, the melt fraction is a function of two dimensionless groups. For the analytical approximation, it is shown that the melt fraction is governed by a single dimensionless group and that the molten layer thickness is governed by two dimensionless groups.

scholarly journals Evaluation and Improvement of PCM Melting in Double Tube Heat Exchangers Using Different Combinations of Nanoparticles and PCM (The Case of Renewable Energy Systems)

2021 ◽  
Vol 13 (19) ◽  
pp. 10675
Author(s):  
Ali Motevali ◽  
Mohammadreza Hasandust Rostami ◽  
Gholamhassan Najafi ◽  
Wei-Mon Yan
Keyword(s):  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Heat Exchangers ◽  
Storage System ◽  
Melting Process ◽  
Energy Storage System ◽  
Melting Rate ◽  
Thermal Energy Storage System ◽  
Dispersion Of Nanoparticles

In this work, the melting process of phase change material (PCM) in double tube heat exchangers was investigated and evaluated through the use of different combinations (1, 2, 3% Nano-Enhanced PCM and 1, 3, 5% Nano-HTF) of GQD, as well as SWCNT nanoparticles and PCM (RT82). In this study, the effect of three different methods, namely the dispersion of nanoparticles in PCM (nano-enhanced PCM), the dispersion of nanoparticles in HTF (nano-HTF), and the simultaneous dispersion of nanoparticles in PCM and HTF (nano-enhanced PCM, nano-HTF) concerning the nanoparticles participation in the thermal energy storage system in a double tube heat exchanger was evaluated. Other effective factors, such as the inlet fluid temperature, different Reynolds numbers, fin as well as new parameter of pipe, and fin thickness were also evaluated. The results showed that the highest effect of different parameters on the PCM melting process was related to the 1% nano-HTF and 3% nano-enhanced PCM nanoparticles of SWCNT, which decreased the PCM melting rate by about 39%. The evaluation of the effect of pipe and fan thickness also showed that the melting rate improved by 31% through reducing the thickness of the HTF fin and pipe. In general, the current study followed two purposes first, to examine three methods of the dispersion of nanoparticles in the thermal energy storage system; second, to reduce the thickness of the tube and fin. Findings of the study yielded positive results.

Experiments on Melting of Unfixed Ice in a Horizontal Cylindrical Capsule

1987 ◽  
Vol 109 (2) ◽  
pp. 454-459 ◽  
Author(s):  
B. W. Webb ◽  
M. K. Moallemi ◽  
R. Viskanta
Keyword(s):  
Natural Convection ◽  
Flow Structure ◽  
Close Contact ◽  
Flow Regimes ◽  
Melting Process ◽  
Contact Melting ◽  
Cylinder Wall ◽  
Liquid Region ◽  
Inversion Point ◽  
Heated Cylinder

Melting of unrestrained ice in a horizontal cylindrical capsule has been investigated experimentally to determine the interaction of fluid flow induced by motion of the solid and natural convection with density inversion of the water–ice system. During the melting process the ice is drawn by buoyancy to the top of the heated cylinder where close-contact melting occurs. Natural convection-dominated melting whose intensity depends on wall temperature prevails in the liquid region below. Three distinct flow regimes were identified for the cylinder wall temperatures of 3.5, 7, and 12° C studied. The flow structure for temperatures below the inversion point is similar to that for melting of unfixed n-heptadecane reported previously. Photographs of flow regimes are presented, and dependence of the solid–liquid interface morphology on the flow structure is discussed.

Numerical Simulation Study of Consumable Electrode Melting Process in Electro-Slag Remelting Ingots

2011 ◽  
Vol 189-193 ◽  
pp. 3895-3898 ◽  
Author(s):  
Lei Rao ◽  
Qi Yao Hu ◽  
Xiao Long Li
Keyword(s):  
Mathematical Model ◽  
Droplet Diameter ◽  
Melting Process ◽  
Melting Rate ◽  
Entire System ◽  
Technological Parameters ◽  
High Quality ◽  
Diameter Droplet ◽  
Melting Current

Electro-slag remelting (ESR) is a kind of special metallurgy techniques to produce high quality alloy materials. The interface of electrode and slag is the energy entrance of entire system in the remelting process. Mathematical model of consumable electrode’s melting process has been built in this paper. Some valuable variation rules of droplet diameter, droplet forming time, melting rate and purification coefficient following melting current and slag bath depth have been studied through a series of simulation work. Based on the mechanism studying of the consumable electrode’s melting, some meaningful experience to optimize the technological parameters and improve material quality of electro slag ingot has been gotten.

Solving the Problem of Silicon Dioxide Melting Based on Deviation Model

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Yuhan Sun
Keyword(s):  
Silicon Dioxide ◽  
Blast Furnace Slag ◽  
Melting Process ◽  
Melting Rate ◽  
Dissolution Behavior ◽  
Characteristic Parameters ◽  
Contour Feature ◽  
Time Periods ◽  
Main Component ◽  
Furnace Slag

Abstract: In order to reveal the dissolution behavior of iron tailings in blast furnace slag, we studied the main component of silica in iron tailings. First, edge contour features need to be established to represent the melting process of silica. We choose shape, perimeter, area and generalized radius as objects. By independently analyzing the influence of these four indexes on the melting rate, the area and shape were selected as the characteristic parameters of the edge contour of the silica particles. Then, the actual melting rate of the silica is estimated by the edge contour feature index. Finally, we can calculate the melting rate of the first second of three time periods of 0.00010312mm3/s，0.0002399mm3/s，0.0000538mm3/s.

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