scholarly journals Cooling Performance and Thermal Radiation Model of Asphalt Mixture with Modified Infrared Powder

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 245
Author(s):  
Lei Gao ◽  
Yanping Liu ◽  
Jianguang Xie ◽  
Zhaoxu Yang
Keyword(s):  
Thermal Radiation ◽  
Asphalt Mixture ◽  
Radiant Heat ◽  
Equilibrium Temperature ◽  
Radiant Heat Transfer ◽  
Radiation Model ◽  
Compact Structure ◽  
Cooling Performance ◽  
Heat Transfer Theory ◽  
Asphalt Mortar

This research studied a new material named modified infrared powder (MIRP) for decreasing the high temperature of asphalt pavements which can help alleviate the urban heat island effect to some extent. Based on the physical apparent density tests of materials and infrared thermal radiation test, the cooling performance of MIRP was obtained. X-ray diffraction analysis and scanning electron microscopy test (SEM) were conducted to analyze the chemical composition and the microstructure of MIRP, respectively. According to the radiant heat transfer theory, a thermal radiation model of the pavement equilibrium temperature was established by microscopic and chemical analysis to study the influence of thermal radiation asphalt mixture and reveal its cooling performance. The results show that the main components of MIRP are metal oxides and nonmetallic oxides which improve its infrared emissivity. Compared with limestone mineral powder asphalt mortar, the asphalt mortar with MIRP had a more compact structure and uniform distribution, and enhanced the overall structural performance of the mixture. The thermal radiation model reveals that the pavement equilibrium temperature combined with the MIRP in asphalt mixture decreases with the increase of the longwave emissivity, and it diminishes with the decrease of the shortwave absorptivity.

Heat Transfer by Simultaneous Conduction and Radiation in an Absorbing Medium

1962 ◽  
Vol 84 (1) ◽  
pp. 63-72 ◽  
Author(s):  
R. Viskanta ◽  
R. J. Grosh
Keyword(s):  
Heat Transfer ◽  
Thermal Radiation ◽  
Radiant Heat ◽  
Radiant Heat Transfer ◽  
Dimensional System ◽  
Parallel Plates ◽  
Approximate Methods ◽  
One Dimensional ◽  
Finite Distance ◽  
Transfer Problems

Heat transfer by simultaneous conduction and radiation in a thermal radiation absorbing and emitting medium is considered. Consideration is given to a one-dimensional system consisting of two, diffuse, nonblack, infinite, isothermal, parallel plates separated by a finite distance. The space between the plates is filled with a thermal radiation absorbing and emitting medium. The problem is formulated in terms of a nonlinear integro-differential equation and the solution is obtained by reducing it to a nonlinear integral equation. The numerical results are obtained by an iterative method. The temperature distributions and heat transfer are calculated. Two approximate methods for formulating radiant heat-transfer problems are presented and comparisons of the results are made with the most exact solution.

Analyzing steam transfer though various flame-retardant fabric assemblies in radiant heat exposure

2016 ◽  
Vol 47 (5) ◽  
pp. 853-869 ◽  
Author(s):  
Yun Su ◽  
Jun Li
Keyword(s):  
Thermal Radiation ◽  
Thermal Energy ◽  
Thermal Protection ◽  
Heat Exposure ◽  
Radiant Heat ◽  
Positive Influence ◽  
Air Permeability ◽  
Fabric System ◽  
Layered Fabric ◽  
Nonfatal Injuries

Protection from steam burns is beneficial to reduce the nonfatal injuries of firefighters in firefighting and rescue operations. A new multifunctional testing apparatus was employed to study heat and steam transfer in protective clothing under low-pressure steam and low-level thermal radiation. Single-, double-, and triple-layered fabric assemblies were selected in this experiment. It is indicated that the existence of hot steam weakens the positive influence of the fabric’s thickness, but increases the importance of the air permeability on the thermal protection. The fabric assemblies entrapping moisture barrier can better resist the penetration of steam through the fabric system, and significantly improve the thermal protection in low steam and thermal radiation exposure due to the low air permeability. Additionally, the total transmitted energy ( Qe) and dry thermal energy ( Qd) under low steam and thermal radiation are dramatically larger than that under thermal radiation ( p < 0.05), while hot steam insignificantly reduces the thermal energy during the cooling ( p = 0.143 > 0.05). The understanding of steam heat transfer helps to provide proper guidance to improve the thermal protection of the firefighter’s clothing and reduce steam burns.

Radiant Heat Transfer From Isothermal Dispersions With Isotropic Scattering

1967 ◽  
Vol 89 (4) ◽  
pp. 300-308 ◽  
Author(s):  
R. H. Edwards ◽  
R. P. Bobco
Keyword(s):  
Heat Transfer ◽  
Approximate Solutions ◽  
Radiant Heat ◽  
Second Order ◽  
Isotropic Scattering ◽  
Radiant Heat Transfer ◽  
Approximate Methods ◽  
First Order ◽  
Order Solution ◽  
Radiant Transfer

Two approximate methods are presented for making radiant heat-transfer computations from gray, isothermal dispersions which absorb, emit, and scatter isotropically. The integrodifferential equation of radiant transfer is solved using moment techniques to obtain a first-order solution. A second-order solution is found by iteration. The approximate solutions are compared to exact solutions found in the literature of astrophysics for the case of a plane-parallel geometry. The exact and approximate solutions are both expressed in terms of directional and hemispherical emissivities at a boundary. The comparison for a slab, which is neither optically thin nor thick (τ = 1), indicates that the second-order solution is accurate to within 10 percent for both directional and hemispherical properties. These results suggest that relatively simple techniques may be used to make design computations for more complex geometries and boundary conditions.

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