scholarly journals Numerical simulation of an instrument to determine the thermal conductivity of conductive solids

2016 ◽  
Vol 18 (1) ◽  
pp. 105
Author(s):  
J. Xamán ◽  
J. Esquivel-Ramon ◽  
Y. Chávez ◽  
I. Hernández-Pérez
Keyword(s):  
Thermal Conductivity ◽  
Numerical Simulation

Numerical Simulation & Experimental Investigation of SMT Laser Microsoldering Thermal Process

1991 ◽  
Vol 226 ◽  
Author(s):  
Wang Chunqing ◽  
Qian Yiyu ◽  
Jiang Yihong
Keyword(s):  
Thermal Conductivity ◽  
Numerical Simulation ◽  
Experimental Investigation ◽  
Thermal Process ◽  
Light Wave ◽  
Light Reflection ◽  
Lead Wire ◽  
Wire Surface ◽  
Conductivity Variation ◽  
Thermal Conductivity Variation

AbstractIn this paper,a numerical simulation of thermal process in the SMT laser microsoldering joint has been developed, in which, the influence on thermal process of the factors such as the thermal conductivity variation of solder with temperature, light reflection coefficient of the lead wire surface, and heat exchange on the surface of SMT materials all have been considered. In order to carry this numerical calculation practice and prove it's results,the reflexive characteristic of light wave to the SMT materials has been gauged,and the dynamic temperature process of laser microjoint has been measured by a new experimental method which was invented by the authors.The results of numerical simulation have been borne out by the tests, and the influences of heating parameters on thermal process has been analysed in this paper.The conclusions will be advantageous to the further study of the microjoint quality control in the SMT laser microsoldering.

scholarly journals Numerical Simulation of Natural Convection in a Transient Short-Hot-Wire Thermal Conductivity Cell

Netsu Bussei ◽  
2008 ◽  
Vol 22 (4) ◽  
pp. 217-222 ◽  
Author(s):  
Peter L. Woodfield ◽  
Jun Fukai ◽  
Motoo Fujii ◽  
Yasuyuki Takata ◽  
Kanei Shinzato
Keyword(s):  
Thermal Conductivity ◽  
Numerical Simulation ◽  
Natural Convection ◽  
Hot Wire ◽  
Transient Short Hot Wire ◽  
Thermal Conductivity Cell ◽  
Conductivity Cell

scholarly journals Numerical simulation of magma intrusion on the thermal evolution of low rank coal

2021 ◽  
Author(s):  
Jingyu Jiang ◽  
Ke Zhao ◽  
Yuanping Cheng ◽  
Shaojie Zheng ◽  
Shuo Zhang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Numerical Simulation ◽  
Coal Seam ◽  
Water Content ◽  
Thermal Evolution ◽  
Low Rank ◽  
Maximum Temperature ◽  
High Water Content ◽  
Low Rank Coal ◽  
Magma Intrusion

Abstract To study the effect of magma intrusion on the thermal evolution of low-rank coal with high water content, the mathematical relationship between water content variation and thermal conductivity of low-rank coal was analyzed by COMSOL Multiphysics numerical simulation and field validation. Taking Daxing Mine in Tiefa coalfield as the research background, the effects of magma finite time intrusion mechanism and water volatilization in coal on thermal evolution and organic maturity of coal seam are investigated in this paper. The results show that as the sill thickness increases, the thermal evolution temperature of the coal seam increases, the required thermal evolution time increases and the final retention temperature increases after the coal seam is cooled down. Approaching the magma, the maximum temperature that the coal seam can reach increases, the maximum temperature lasts longer, and the final temperature retained by the coal seam becomes higher. The increase of water content of coal makes the thermal conductivity increase, and the rate of heat transfer from coal seam is accelerated, and more heat is transferred to distant places in the same time. At the same time, the heat lost by the magma in the same time increases, the time required for the cooling of the magma decreases, and the maximum temperature reached by the underlying coal seam is significantly lower. The presence of moisture weakens the thermal evolution of the magma to the coal seam and reduces the expected maturity of the coal. The results of average random vitrinite reflectance (Ro) and moisture examination of coal samples collected at the Daxing Mine site verified the numerical simulation results of magma thermal evolution.

scholarly journals The numerical simulation of enhanced heat transfer on a Linear Fresnel molten salt-type receiver tube filled with porous media

2019 ◽  
Vol 118 ◽  
pp. 01041
Author(s):  
Chenggang Yang ◽  
Yuning Zhang ◽  
Fenghe Yan ◽  
Wenguang Zhang ◽  
Wei Li
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Numerical Simulation ◽  
Porous Media ◽  
Molten Salt ◽  
Temperature Difference ◽  
Wall Temperature ◽  
Three Dimensional ◽  
Heat Transfer Fluid ◽  
Filling Rate

In this paper, three-dimensional numerical simulation was taken on a Linear Fresnel solar receiver tube using molten salt as heat transfer fluid (HTF), in which the porous media was filled to enhance the heat transfer efficiency. The simulation was to analyze the influence of the different conditions (filling rate, porosity and thermal conductivity) on heat transfer effect and wall temperature difference. The results revealed that the Nu (Nusselt number) increased firstly and then decreased with the increasing filling rate in both center filling and annular filling types. The optimal thermal performance were obtained when filling rate were 0.8 and 0.2 in center filling and annular filling, respectively. The Nu were about 1.7 and 1.5 times as the clear receiver. The circumferential temperature difference decreased firstly and then increased with filling rate increasing in both center filling and annular filling types. The lowest circumferential temperature differences were achieved at the filling rate 0.8 and 0.4 in center filling and annular filling types, and temperature difference decreased 15.88°C and 22°C compared with clear receiver, respectively. The Nu and PEC both decreased with porosity increasing. However, the thermal conductivity of porous media had little influence to the Nu and circumferential wall temperature.

A Study of Porosity Influence on Thermal Diffusivity of Aluminium Foam by Experimental Analysis and Numerical Simulation

2010 ◽  
Vol 297-301 ◽  
pp. 814-819 ◽  
Author(s):  
A. Adamčíková ◽  
B. Taraba ◽  
J. Kováčik
Keyword(s):  
Thermal Conductivity ◽  
Numerical Simulation ◽  
Thermal Diffusivity ◽  
Transfer Task ◽  
Aluminium Foam ◽  
Flash Method ◽  
Inverse Heat Transfer ◽  
High Thermal Diffusivity ◽  
Specific Heat Capacities ◽  
Measured Specific Heat

Aluminium foam is a unique material possessing very high thermal diffusivity due to high thermal conductivity of the cell walls accompanied with rather low overall thermal conductivity, controlled via porosity [1]. There is a presumption of increasing influence at thermal diffusivity of aluminium foam by decreasing porosity, following the presented results (e.g. by using the transient plane source method [2]) and relation between thermal diffusivity and density. Thermal diffusivity of aluminium foam considering various porosity and various compositions of precursors were observed. The Aluminium foam was prepared by the powder metallurgy route, also well known as the ALULIGHT process, and various densities were achieved by changing of parameters (temperature, time) of foaming. The following types of foamable precursors were used: AlMg1Si0.6, AlSi10, as blowing agent was used 0.8 wt. % of TiH2.The thermal diffusivity of particular precursors by the flash method was measured. Specific heat capacities of samples with different density were measured by a calorimeter for various temperatures. The coefficient of thermal conductivity as a function of temperature was calculated by heat transient experiment data and numerical simulation consequently as an inverse heat transfer task. The problem was solved by the finite element method using the engineering-scientific program code ANSYS. The results depend on the thermal diffusivity, on the porosity and the type of precursor. Despite that aluminium foam is considered as a type of composite, thermophysical properties could be calculated upon known volume of aluminium alloy and air in the pores However there is a presumption that this rule cannot be used in case of porous materials. Values obtained by the mentioned methodology shown a significant influence on the porosity and the thermal diffusivity of the aluminium foam.

Sign in / Sign up

Export Citation Format

Share Document