A 3-D numerical heat transfer model for silica aerogels based on the porous secondary nanoparticle aggregate structure

This paper presents the results of a study to compare the heat transfer characteristics of silica aerogels to that of air. A small window unit was made with a section having monolithic silica aerogels sandwiched between two plates of window glass. Another section had just an air space in between. Upon constant heating, steady state temperature measurements were made across the window unit. These data were used to infer apparent thermal resistance values for each case. The measured results showed that the aerogel insulation had a thermal resistance approximately 20% greater than that of air alone. A numerical heat transfer model of the system was developed in Cosmosworks. The model was used to match the experimental results and determine calculated thermal conductivity values for each of the interface cases: silica aerogel and air. The calculated thermal conductivity value of the aerogel matched well with typical values for this material. The calculated value for air though was approximately four times higher than the published value. This difference was attributed to the occurrence of free convection in the air space which was not accounted for in the model.

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Numerical Heat Transfer Model of Buried Pipe and Ground Thermal Conductivity Measurement

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.99-100.112 ◽

2011 ◽

Vol 99-100 ◽

pp. 112-115

Author(s):

Ming Zhi Yu ◽

Lei Zhang ◽

Xiao Fei Yu ◽

Zhao Hong Fang

Keyword(s):

Heat Transfer ◽

Thermal Conductivity ◽

Estimation Method ◽

Conductivity Measurement ◽

Heat Transfer Model ◽

Parameters Estimation ◽

Transfer Model ◽

Buried Pipe ◽

Geothermal Heat ◽

Numerical Heat Transfer

A two dimensional numerical heat transfer model of buried geothermal heat exchanger has been established by finite element method. This model is used to analyse the heat transfer between buried vertical pipes and the ground, and determine the ground thermal properties together with parameters estimation method. The ground thermal conductivity of an actual project was measured and the analysis shows that the results can be used for engineering design.

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Development of efficient numerical heat transfer model coupled with genetic algorithm based optimisation for prediction of process variables in GTA spot welding

Science and Technology of Welding & Joining ◽

10.1179/136217108x356791 ◽

2009 ◽

Vol 14 (4) ◽

pp. 333-345 ◽

Cited By ~ 6

Author(s):

S. Bag ◽

A. De

Keyword(s):

Heat Transfer ◽

Genetic Algorithm ◽

Spot Welding ◽

Heat Transfer Model ◽

Transfer Model ◽

Process Variables ◽

Numerical Heat Transfer

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Effects of structural parameters on the thermal insulation properties of coated carbon fiber fabrics

Textile Research Journal ◽

10.1177/0040517519896759 ◽

2019 ◽

Vol 90 (13-14) ◽

pp. 1549-1557

Author(s):

Qian Zhang ◽

Zhenrong Zheng ◽

Kezhu Mao ◽

Wei Zhi ◽

Lijuan Luo ◽

...

Keyword(s):

Heat Transfer ◽

Carbon Fiber ◽

Thermal Insulation ◽

Structural Parameters ◽

Heat Transfer Model ◽

Transfer Model ◽

Numerical Heat Transfer ◽

Structure Density ◽

Coated Carbon ◽

Insulation Performance

In order to predict the thermal insulation performance of coated carbon fiber fabric, a numerical heat transfer model under high temperature was established. The simulation results were validated by quartz lamp ablation experiment. The experimental values were in agreement with the numerical values, and the average relative error between them was 9.47%. Furthermore, the impact of structural parameters on the thermal insulation of coated carbon fiber fabrics, by using the numerical heat transfer model, was investigated. The results show that thermal insulation for the samples is in the order of plain < 2/1 twill < 3/3 twill < 5/3 stain, when using constant structure density and yarn fineness. Thermal insulation performance of the samples dramatically increases as yarn fineness goes from 3 to 12 K. Furthermore, when the structure density increases to more than 70 ends/10 cm, the thermal insulation property shows an increasing trend.

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