A control-volume based finite-element model for solid/liquid phase change including natural convection

1986 ◽  
Author(s):  
G. SCHNEIDER
Keyword(s):  
Finite Element ◽  
Natural Convection ◽  
Liquid Phase ◽  
Finite Element Model ◽  
Phase Change ◽  
Control Volume ◽  
Element Model ◽  
Solid Liquid

scholarly journals Parallel finite-element codes for the simulation of two-dimensional and three-dimensional solid–liquid phase-change systems with natural convection

2020 ◽  
Vol 257 ◽  
pp. 107492
Author(s):  
Georges Sadaka ◽  
Aina Rakotondrandisa ◽  
Pierre-Henri Tournier ◽  
Francky Luddens ◽  
Corentin Lothodé ◽  
...  
Keyword(s):  
Finite Element ◽  
Natural Convection ◽  
Liquid Phase ◽  
Phase Change ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Parallel Finite Element ◽  
Solid Liquid

scholarly journals Integral Solution of Two-Region Solid–Liquid Phase Change in Annular Geometries and Application to Phase Change Materials–Air Heat Exchangers

Energies ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 4474 ◽  
Author(s):  
Hamidreza Shabgard ◽  
Weiwei Zhu ◽  
Amir Faghri
Keyword(s):  
Liquid Phase ◽  
Boundary Conditions ◽  
Phase Change ◽  
Phase Change Materials ◽  
Volume Fraction ◽  
Control Volume ◽  
Solid Volume Fraction ◽  
Solidification Time ◽  
Design And Optimization ◽  
Solid Liquid

A mathematical model based on the integral method is developed to solve the problem of conduction-controlled solid–liquid phase change in annular geometries with temperature gradients in both phases. The inner and outer boundaries of the annulus were subject to convective, constant temperature or adiabatic boundary conditions. The developed model was validated by comparison with control volume-based computational results using the temperature-transforming phase change model, and an excellent agreement was achieved. The model was used to conduct parametric studies on the effect of annuli geometry, thermophysical properties of the phase change materials (PCM), and thermal boundary conditions on the dynamics of phase change. For an initially liquid PCM, it was found that increasing the radii ratio increased the total solidification time. Also, increasing the Biot number at the cooled (heated) boundary and Stefan number of the solid (liquid) PCM, decreased (increased) the solidification time and resulted in a greater (smaller) solid volume fraction at steady state. The application of the developed method was demonstrated by design and analysis of a PCM–air heat exchanger for HVAC systems. The model can also be easily employed for design and optimization of annular PCM systems for all associated applications in a fraction of time needed for computational simulations.

Energy Storage With Solid/Liquid Phase Change in Presence of Natural Convection

2001 ◽  
Author(s):  
M. Pinelli ◽  
S. Piva
Keyword(s):  
Natural Convection ◽  
Energy Storage ◽  
Liquid Phase ◽  
Phase Change ◽  
Change Process ◽  
Solid Phase ◽  
High Energy ◽  
Heat Transfer Process ◽  
Phase Change Process ◽  
Solid Liquid

Abstract Solid/liquid phase change process has received great attention for its capability to obtain high energy storage efficiency. In order to analyse these systems, undergoing a solid/liquid phase change, in many situations the heat transfer process can be considered conduction-dominated. However, in the past years, it has been shown that natural convection in the liquid phase can significantly influence the phase change process in terms of temperature distributions, interface displacement and energy storage. In this paper, a procedure to analyse systems undergoing liquid/solid phase change in presence of natural convection in the liquid phase based on the utilisation of a commercial computer code (FLUENT), has been developed. This procedure is applied to a cylinder cavity heated from above and filled with a Phase Change Material. It was found that when the coupling with the environment, even if small, is considered, natural convection in the liquid phase occurs. The numerical results are then compared with available experimental data. The analysis shows that the agreement between numerical and experimental results is significantly improved when the results are obtained considering the presence of circulation in the liquid phase instead of considering the process only conduction-dominated. Furthermore, some interesting features of the flow field are presented and discussed.

A Comparison of a Penalty Finite Element Model with the Stream Function-Vorticity Model of Natural Convection in Enclosures

1980 ◽  
Vol 102 (4) ◽  
pp. 659-666 ◽  
Author(s):  
J. N. Reddy ◽  
Akio Satake
Keyword(s):  
Finite Element ◽  
Natural Convection ◽  
Finite Element Model ◽  
Stream Function ◽  
Penalty Function ◽  
Degrees Of Freedom ◽  
Element Model ◽  
Flow And Heat Transfer ◽  
Natural Connection ◽  
Function Formulation

This paper is concerned with a comparative study of the stream function-vorticity formulation and penalty function formulation of the two-dimensional equations governing natural connection in enclosures. The penalty function formulation presented herein is the only correct way of describing it for the problem at hand. The penalty-finite element model developed herein is novel with this work, and involves two velocities, temperature, and stream function as degrees of freedom at each node. The model includes, as a special case, the penalty-finite element model of natural convection in enclosures reported in the literature. Numerical results obtained using the two formulations are compared for several geometries, and boundary conditions, and the effects of Rayleigh number and Prandtl number on the flow and heat transfer are studied.

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