A steady heat transfer model of hollow double glazing under entire wave length heat radiation

2014 ◽  
Vol 81 ◽  
pp. 72-83 ◽  
Author(s):  
Tian-Peng Wang ◽  
Liang-Bi Wang
2014 ◽  
Vol 924 ◽  
pp. 329-335 ◽  
Author(s):  
Cong Hang Li ◽  
Shi Chen Jiang ◽  
Zheng Ping Yao ◽  
Song Sheng ◽  
Xin Jian Jiang ◽  
...  

Based on the nanoporous network structure features of silica aerogel, the gas-solid coupled heat transfer model of silica aerogel is analyzed, and the calculation formulas of the gas-solid coupled, the gas thermal conductivity and the heat radiation within the aerogel are derived. The thermal conductivity of pure silica aerogel is calculated according to the derived heat transfer model and is also experimentally measured. Moreover, measurements on the thermal conductivities of silica aerogel composites with different densities at ambient conditions are performed. And finally, a novel design of silica aerogel based integrated structure and thermal insulation used for withstanding the harsh thermal environment on the Martin surface is presented.


2016 ◽  
Vol 685 ◽  
pp. 90-93
Author(s):  
Alexander Yu. Chebotarev ◽  
Andrey E. Kovtanyuk

A boundary multiplicative control problem for a nonlinear steady-state heat transfer model accounting for heat radiation effects is considered. The aim of control consists in obtaining a prescribed temperature or radiative intensity distributions in a part of the model domain by controlling the boundary reflectivity. The solvability of this control problem is proved, and optimality conditions are derived.


2016 ◽  
Vol 836-837 ◽  
pp. 430-435
Author(s):  
Huan Lu ◽  
Shu Long Wang ◽  
Ning He ◽  
Liang Li ◽  
Xiu Qing Hao

Laser assisted machining (LAM) is one important solution for machining difficult-to-machine materials. The heat transfer model of quasi steady state in laser assisted micro machining is built, and the simulation software for temperature distribution measurement is developed based on MATLAB. The simulated temperature distribution of the ZrO2 ceramic heated by pulse laser shows a good agreement of tendency with the corresponding experimental results through the infrared temperature measurement method, while the simulated temperature is consistently overestimated. This difference maybe results from the neglect of the heat loss caused by the heat radiation and the heat convection in the model. The proposed model in this paper could provide reference for the selection of optimal process parameters and improve the machining quality, which are closely related to the temperature distribution.


2019 ◽  
Vol 13 (11) ◽  
pp. 21
Author(s):  
Man-Jing Li ◽  
Mao Zhu ◽  
Jia-Xu Han ◽  
Yuan-Biao Zhang

The thermal protective clothing for high-temperature operation usually consists of three-layer fabrics and a gap called the air layer or Layer IV between Layer III and skin. In order to design more effective thermal protective clothing at less cost, based on the heat transfer principles, we establish heat transfer models of fabrics and air layer, which are one-dimensional nonlinear partial differential equations with constant coefficients. In the three-layer fabrics, we consider the effects of heat conduction and heat radiation in Layer I but only consider heat conduction in Layer II and Layer III. Furthermore, the heat transfer model of Layer IV is decoupled and simplified to steady-state heat conduction in Layer IV and radiation heat transfer on surface of Layer IV. According to the explicit difference schemes for the models, we use the parameters in an experiment which puts a thermal manikin in high-temperature environment for some time and measures the temperature of lateral skin at regular time, to solve the models and calculate the temperature of each layer. With MATLAB, the visual interface of three-dimensional temperature distribution is provided, which is reference for functional design of thermal protective clothing. We also compare the simulation result of skin surface with the experimental data. The results show that at the same position, the temperature rises over time but with decreasing rate and finally reaches the steady state. Moreover, at one moment after reaching the steady state, the temperature has a gradual decrease with the increase of distance from the external environment.


2013 ◽  
Vol 706-708 ◽  
pp. 152-157
Author(s):  
Tang Wei Liu ◽  
He Hua Xu ◽  
Xue Lin Qiu ◽  
Xiao Bin Shi

In this paper, for heat conductivity identification of three dimension steady heat transfer model of composite materials, a new hybrid Tikhonov regularization mixed multiscale finite-element method is present. First the mathematical models of the forward and the coefficient inverse problems are discussed. Then the forward model is solved by mixed multiscale FEM which utilizes the effects of fine-scale heterogeneities through basis functions formulation computed from local heat transfer problems. At last the numerical approximation of inverse coefficient problem is obtained by Tikhonov regularization method.


2018 ◽  
Vol 1 (1) ◽  
pp. 142-150
Author(s):  
Murat Tunc ◽  
Ayse Nur Esen ◽  
Doruk Sen ◽  
Ahmet Karakas

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.


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