scholarly journals A Numerical Method for Analysing Heat Conduction in Composites Containing Encapsulated Phase Change Materials

2018 ◽  
Vol 237 ◽  
pp. 02012
Author(s):  
Hui Wang ◽  
Qing-Hua Qin
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Composite System ◽  
Matrix Material ◽  
Heat Transfer Model ◽  
Transient Heat Transfer ◽  
Cement Matrix ◽  
Transfer Model ◽  
Two Phase ◽  
Three Phase

In this study, a three-dimensional transient heat transfer model in a three-phase composite system is established to investigate effects of temperature reduction in a composite system due to the use of encapsulated phase change material (PCM). The entire composite system is composed of cement matrix material, PCM, and hollow metal microspheres (HMSs) which are introduced to accelerate the phase change efficiency of the PCM and to simultaneously hold the liquid phase of the PCM. The present transient heat transfer model is numerically solved via finite element technique for investigating the transient thermal performance of the three-phase composite system. The temperature distribution on the specific area is compared to that in the pure cement material and the two-phase composite system without metal shell for demonstrating the ability of temperature adjustment of the PCM. Finally, effects of the spatial distribution of HMS on the temperature variation in the three-phase composite system is further investigated to provide comprehensive understanding on energy adjustment of this composite system.

Theoretical Post-Dryout Heat Transfer Model

2018 ◽  
Vol 1 (1) ◽  
pp. 142-150
Author(s):  
Murat Tunc ◽  
Ayse Nur Esen ◽  
Doruk Sen ◽  
Ahmet Karakas
Keyword(s):  
Heat Transfer ◽  
Droplet Diameter ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Operating Pressure ◽  
Vertical Pipe ◽  
Two Phase ◽  
Experimental Values ◽  
Reactor Operating ◽  
Coolant System

A theoretical post-dryout heat transfer model is developed for two-phase dispersed flow, one-dimensional vertical pipe in a post-CHF regime. Because of the presence of average droplet diameter lower bound in a two-phase sparse flow. Droplet diameter is also calculated. Obtained results are compared with experimental values. Experimental data is used two-phase flow steam-water in VVER-1200, reactor coolant system, reactor operating pressure is 16.2 MPa. On heater rod surface, dryout was detected as a result of jumping increase of the heater rod surface temperature. Results obtained display lower droplet dimensions than the experimentally obtained values.

Transient Heat Transfer Simulation of the Coupling 3-D Moving Piston Assembly-Lubricant Film-Liner System

2006 ◽  
Author(s):  
Liu Zhien ◽  
Jiang Yankun ◽  
Chen Guohua ◽  
Yang Wanli
Keyword(s):  
Heat Transfer ◽  
Piston Ring ◽  
Cylinder Liner ◽  
Heat Transfer Model ◽  
Lubricant Film ◽  
Transient Heat Transfer ◽  
Transfer Model ◽  
Friction Heat ◽  
Liner System ◽  
Piston Assembly

Transient heat transfer model of the coupling 3-D moving piston assembly-lubricant film-liner system is successfully developed for predicting the temperature distributions in the component system of internal combustion chamber, in which the effect of the friction heat generated at the piston ring/cylinder liner interfaces has been taken into account. The finite element method (FEM) is employed in the model for establishing the heat transfer relation among the moving piston assembly-lubricant film-cylinder liner. The 3-D discrete model of the coupling system is obtained by hypothesizing the lubricant film as 1-D thermal resistances and the friction heat as heat flux boundary conditions. The allocation and distribution model of friction heat on piston ring pack and liner are also established. The 3-D coupling heat transfer model has been used to analyze the heat transfer of a gasoline engine.

Development of transient heat transfer model for controlled gradient drilling

2019 ◽  
Vol 148 ◽  
pp. 331-339 ◽  
Author(s):  
Hongwei Yang ◽  
Jun Li ◽  
Gonghui Liu ◽  
Jiangshuai Wang ◽  
Kuidong Luo ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Model ◽  
Transient Heat Transfer ◽  
Transfer Model

Improvement of Transient Heat Transfer Models for the Coupled 3-D Moving Piston Assembly-Liner System

2007 ◽  
Author(s):  
Yankun Jiang ◽  
Zhien Liu ◽  
Rolf D. Reitz ◽  
Zheling Dong ◽  
Xiaoming Ye
Keyword(s):  
Heat Transfer ◽  
Gasoline Engine ◽  
Sparse Matrix ◽  
Cylinder Liner ◽  
Heat Transfer Model ◽  
Transient Heat Transfer ◽  
Transfer Model ◽  
Piston Rings ◽  
Liner System ◽  
Piston Assembly

A transient heat transfer model for the coupling 3-D moving piston assembly-liner system has been successfully improved for predicting temperature distributions in the components of internal combustion engine chamber. In the model the effect of the 3-D friction heat generated at the piston ring/cylinder liner interfaces and the multi-dimensional lubricant film thickness between the piston rings and the liner has been taken into account. A directly coupled finite element method (FEM) is employed in the model for establishing the heat transfer relation among the moving piston assembly-cylinder liner components. A 3-D discrete model of the coupling system is formulated, which includes the piston rings, piston, liner and cylinder. Due to the complexity of the temperature stiffness matrix, a sparse matrix data structure is employed in the model to save the memory and calculation time. Finally, the 3-D coupling heat transfer model has been used to analyze heat transfer processes in a gasoline engine.

Flow Boiling in Horizontal Tubes: Part 3—Development of a New Heat Transfer Model Based on Flow Pattern

1998 ◽  
Vol 120 (1) ◽  
pp. 156-165 ◽  
Author(s):  
N. Kattan ◽  
J. R. Thome ◽  
D. Favrat
Keyword(s):  
Heat Transfer ◽  
Annular Flow ◽  
Flow Boiling ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Two Phase ◽  
Horizontal Tubes ◽  
High Vapor ◽  
Coefficient Versus ◽  
The Heat Transfer Coefficient

A new heat transfer model for intube flow boiling in horizontal plain tubes is proposed that incorporates the effects of local two-phase flow patterns, flow stratification, and partial dryout in annular flow. Significantly, the local peak in the heat transfer coefficient versus vapor quality can now be determined from the prediction of the location of onset of partial dryout in annular flow. The new method accurately predicts a large, new database of flow boiling data, and is particularly better than existing methods at high vapor qualities (x > 85 percent) and for stratified types of flows.

Parallel Heat Transfer Model of a Panel with Phase Change Material for Thermal Storage Applications Computed on Graphics Processing Units

2014 ◽  
Vol 1077 ◽  
pp. 118-123 ◽  
Author(s):  
Lubomír Klimeš ◽  
Pavel Charvát ◽  
Milan Ostrý ◽  
Josef Stetina
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Phase Change Material ◽  
Graphics Processing Units ◽  
Parallel Implementation ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Wide Range ◽  
Graphics Processing ◽  
Change Material

Phase change materials have a wide range of application including thermal energy storage in building structures, solar air collectors, heat storage units and exchangers. Such applications often utilize a commercially produced phase change material enclosed in a thin panel (container) made of aluminum. A parallel 1D heat transfer model of a container with phase change material was developed by means of the control volume and effective heat capacity methods. The parallel implementation in the CUDA computing architecture allows the model for running on graphics processing units which makes the model very fast in comparison to traditional models computed on a single CPU. The paper presents the model implementation and results of computational model benchmarking carried out with the use of high-level and low-level GPUs NVIDIA.

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