Experimental study of MgO/Mg(OH)2 thermochemical heat storage with direct heat transfer mode

2020 ◽  
Vol 275 ◽  
pp. 115356 ◽  
Author(s):  
J. Yan ◽  
Z.H. Pan ◽  
C.Y. Zhao
Author(s):  
Manel Kraiem ◽  
Mustapha Karkri ◽  
Sassi Ben Nasrallah ◽  
patrick sobolciak ◽  
Magali Fois ◽  
...  

Thermophysical characterization of three paraffin waxes (RT27, RT21 and RT35HC) is carried out in this study using DSC, TGA and transient plane source technics. Then, a numerical study of their melting in a rectangular enclosure is examined. The enthalpy-porosity approach is used to formulate this problem in order to understand the heat transfer mechanism during the melting process. The analysis of the solid-liquid interface shape, the temperature field shows that the conduction is the dominant heat transfer mode in the beginning of the melting process. It is followed by a transition regime and the natural convection becomes the dominant heat transfer mode. The effects of the Rayleigh number and the aspect ratio of the enclosure on the melting phenomenon are studied and it is found that the intensity of the natural convection increases as the Rayleigh number is higher and the aspect ratio is smaller. In the second part of the numerical study, a comparison of the performance of paraffins waxes during the melting process is conducted. Results reveals that from a kinetically RT21 is the most performant but in term of heat storage capacity, it was inferred that RT35HC is the most efficient PCM.


2013 ◽  
Vol 756-759 ◽  
pp. 1679-1683
Author(s):  
Dong Mei Li ◽  
Xin Chun Wang ◽  
Li Nan Shi ◽  
Bo Chao Qu

This article focuses on heat conduction problems in the process of steel industry. Modeling the direct problems of heat transfer, establish heat conduction and thermal radiation model. Model discretization method are used, discussion process from one dimension to two. We give the difference schemes, and the numerical example. Through the results we compare differences between one and two dimensional models, and the impact to the results of the two heat transfer mode.


Author(s):  
Dan Wu ◽  
Hongxing Yu ◽  
Junchong Yu ◽  
Jie Li ◽  
Jiyang Yu

Heat transfer characteristics near the quench front in a reflooding process are quite complex. Large amount of vapor are generated, and the rod clad temperature drops rapidly to near saturation state. Until now, heat transfer mechanism in this region has not been well understood yet. Best estimate codes like RELAP5, COBRA-TF tend to treat the heat transfer mode near the quench front as transition boiling. However, when calculating the reflooding phase of tight lattice, these codes always under-predict the quench temperature, and also the slop of the temperature drop is predicted to be less steep than the experimental data. In this paper, a new heat transfer model near the quench front in the reflooding phase of a tight lattice is developed. Instead of transition boiling, transient liquid film evaporation is considered to be the main heat transfer mode in this region. It is supposed that heat released near the quench front is through liquid film evaporation. Through comparisons with experimental data, it can be concluded that the new model can better predict the quench temperature and the temperature drop slop.


1999 ◽  
Vol 121 (2) ◽  
pp. 481-484 ◽  
Author(s):  
M. R. Jones

The design of heat transfer systems in which radiation is the dominant heat transfer mode is an important industrial problem. Compared to the conventional forward approach, the inverse approach allows a more thorough analysis of a potential design. This note demonstrates that inverse methods can be powerful tools in the analysis of radiative heat transfer systems.


2021 ◽  
Vol 896 ◽  
pp. 111-116
Author(s):  
Yan Li ◽  
Guo You You ◽  
Zhu Qunzhi

Numerical simulation of the melting of paraffin in the inclined straight channel shows that the melting speed of paraffin is faster in the early stage and gradually slows down in the later stage. It is found that heat conduction is the main heat transfer mode in the early stage of paraffin melting. With the increasing number of liquid paraffin, natural convection occurs in the liquid paraffin. The liquid paraffin with higher temperature flows upward due to the effect of buoyance and lift, and convection heat transfer gradually increases and takes the dominant position in the melting process.


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