scholarly journals Transport of heat through the skin

2017 ◽  
Vol 15 (1) ◽  
pp. 68-71
Author(s):  
Yury I Luchakov ◽  
Petr D Shabanov
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Heat Transport ◽  
Convective Heat ◽  
Human Body ◽  
Blood Stream ◽  
Conductive Heat ◽  
Skin Region ◽  
Superficial Skin ◽  
Different Tissues

The transport of heat through the skin of the human body has been investigated in the paper. The analysis of cytoarchiterture of this region was done, a model of vascular stream of the skin was built where the transient microregion typical for its different tissues was separated. A mathematical model taking part both convective and conductive heat transport was reproduced for this microregion. There was no heat transfer through the blood but only conductive heat transport was shown to be in the superficial skin tissue strates having blood current. In the norm, there was convective heat transport preferably in the deeper skin strates of the hypoderm where arterials and veins of more than 100 and 300 um in diameter were lying. The organism was revealed to able to increase or decrease the skin region where there was only convective or conductive heat transport by means of changing the blood stream. Therefore, the organism is able to change the size of peripheral tissue where there is only convective or only conductive heat transfer according to physiological necessity.

The Effect of Thermal Wall Properties on Natural Convection in Inclined Rectangular Cells

1982 ◽  
Vol 104 (1) ◽  
pp. 111-117 ◽  
Author(s):  
B. A. Meyer ◽  
J. W. Mitchell ◽  
M. M. El-Wakil
Keyword(s):  
Heat Transfer ◽  
Cell Wall ◽  
Natural Convection ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Conductive Heat ◽  
Numerical Work ◽  
Aspect Ratios ◽  
Convection Problem ◽  
Natural Convection Problem

The effects of cell wall thickness and thermal conductivity on natural convective heat transfer within inclined rectangular cells was studied. The cell walls are thin, and the hot and cold surfaces are isothermal. The two-dimensional natural convection problem was solved using finite difference techniques. The parameters studied were cell aspect ratios (A) of 0.5 and 1, Rayleigh numbers (Ra) up to 105, a Prandtl number (Pr) of 0.72 and a tilt angle (φ) of 60 deg. These parameters are of interest in solar collectors. The numerical results are substantiated by experimental results. It was found that convection coefficients for cells with adiabatic walls are substantially higher than those for cells with conducting walls. Correlations are given for estimating the convective heat transfer across the cell and the conductive heat transfer across the cell wall. These correlations are compared with available experimental and numerical work of other authors.

scholarly journals Radiation heat transfer between human and cryocabin walls

2021 ◽  
Vol 2119 (1) ◽  
pp. 012146
Author(s):  
I A Burkov ◽  
S I Khutsieva ◽  
V A Voronov
Keyword(s):  
Heat Transfer ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Human Body ◽  
Transfer Problem ◽  
Radiation Heat Transfer ◽  
Vertical Wall ◽  
Heat Transfer Problem ◽  
Radiation Heat ◽  
The Impact

Abstract The paper considers the particular case of intensive radiation heat transfer in the system consisting of a human body and cryocabin walls of cryosauna. Calculations for three models have been made, namely, human-vertical wall, which is arranged parallel to a human, human-vertical wall, which is positioned at a certain angle, and a human-cryosauna. Analytical calculations are compared with Ansys-bassed numerical calculations. The impact of radiation heat transfer in this radiation-convective heat transfer problem is estimated. Conclusions are drawn about taking into account the radiation heat transfer and a rational method for calculating this heat transfer problem.

Numerical Modeling for the Energy Conversion and Thermal Transmission Accompanying the Process of Oily Cuttings Agitation

2016 ◽  
Author(s):  
Zhipeng Sun ◽  
Hongwu Zhu ◽  
Jian Hua
Keyword(s):  
Heat Transfer ◽  
Energy Conversion ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Solid Phase ◽  
Conductive Heat ◽  
Heat Transmission ◽  
Gas Reservoirs ◽  
Coupling Approach ◽  
Solid Motion

As a kind of unconventional gas reservoirs, shale gas reservoirs are full of potential to develop and have attracted global attention. Accompanying the exploiting of shale gas, a large amount of drilling cuttings contaminated by the oil-based drilling fluid are generated inevitably. How to deal with the drilling cuttings in a environmental-friendly way is tough especially for offshore oilfield. So it is important to investigate this aspect deeply and develop methods to clean the contaminated drilling cuttings. As is known to all, the thermal desorption technology has outstanding performance in oily cuttings cleaning. This paper bases on a kind of mechanical-thermal cuttings cleaning apparatus where the contaminated drilling cuttings are heated up by friction heat produced by the friction between the cuttings and the agitating vanes. And the harmful substance is separated from the cuttings in the agitated and high temperature flow field. This thesis investigates the fundamental of the energy conversion in the frictional process, infer formulas analyzing the thermo-physical phenomena and quantitatively model the energy conversion and thermal transmission accompanying the friction. Firstly, the principle of heat transfer and the law of conservation of energy are employed to investigate the natural law of the energy conversion in the frictional process. Based on the investigation, taking the liquid bridge between the oily cuttings and the agitating vane into account, this paper deduces the physical equations and the frictional energy model to calculate the total frictional heat, heat density and temperature distribution. Following up the frictional model, in the Eulerian-Lagrangian coupling framework, this paper develops a parallel numerical platform of computational fluid dynamics combined with discrete element method (CFD-DEM). In the coupling approach, the gas motion is solved at the computational grid level while the solid motion is resolved at the particle-scale level. Furthermore, the coupling approach is extended with the frictional energy model. The numerical platform can calculate the dense gas-solid motion in the fluidizing apparatus, the convective heat transfer between gas and solid phase, and the conductive heat transfer between particles. Based on the platform, the mechanical-thermal energy conversion and the convective heat transfer between gas and oily cuttings, and the conductive heat transfer between cuttings and the agitating vanes are investigated. Meanwhile an experiment is conducted. By comparing the numerical results with the experiment data, the paper can come to the conclusion that how to dispose the nonlinear parameters such as the friction contact area, the friction coefficient and the normal pressure is the key to accurately model the energy conversion and the heat transmission. What’s more, it can be understood that the convective heat transfer between gas and solid phase play an important role in the heat transmission.

Three-Dimensional Flow Effects on Convective Heat Transfer From a Window Covered by a Simple Plane Blind With No Top Covering

2006 ◽  
Author(s):  
Patrick H. Oosthuizen
Keyword(s):  
Heat Transfer ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Vertical Wall ◽  
Three Dimensional ◽  
Approximate Model ◽  
Conductive Heat ◽  
Three Dimensional Flow ◽  
Dimensional Flow ◽  
Flow Effects

Most studies of convective heat transfer in window-blind systems assume that the flow over the window-blind arrangement is two-dimensional. In some cases, however, three-dimensional flow effects can become important. The present study was undertaken to determine how significant such effects can be for the particular case of a window covered by a simple plane blind. Only convective heat transfer has been considered. The situation considered is only an approximate model of the real window-blind situation. The window is represented by a rectangular vertical isothermal wall section embedded in a large vertical adiabatic plane wall surface and exposed to a large surrounding "room" in which the temperature is lower than the window temperature. The plane blind is represented by a thin vertical wall having the same size as the "window" which offers no resistance to heat transfer across it and in which conductive heat transfer is negligible. The gaps between the blind and the window at the sides and at the top of the window-blind system are assumed to be open. The flow has been assumed to be laminar and it has been assumed that the fluid properties are constant except for the density change with temperature which gives rise to the buoyancy forces. The solution has been obtained by numerically solving the three-dimensional governing equations written in dimensionless form. The effects of the dimensionless governing variables on the window Nusselt number have been numerically examined.

Heat transfer modeling within the microclimate between 3D human body and clothing: effects of ventilation openings and fire intensity

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Miao Tian ◽  
Jun Li
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Temperature Distribution ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Human Body ◽  
Thermal Environment ◽  
Heat Transfer Process ◽  
Fire Intensity ◽  
Content Type

PurposeThe purpose of this study is to determine the effect of ventilation openings and fire intensity on heat transfer and fluid flow within the microclimate between 3D human body and clothing.Design/methodology/approachOn account of interaction effects of fire and ventilation openings on heat transfer process, a 3D transient computational fluid dynamics model considering the real shape of human body and clothing was developed. The model was validated by comparing heat flux history and distribution with experimental results. Heat transfer modes and fluid flow were investigated under three levels of fire intensity for the microclimate with ventilation openings and closures.FindingsTemperature distribution on skin surface with open microclimate was heavily depended on the heat transfer through ventilation openings. Higher temperature for the clothing with confined microclimate was affected by the position and direction of flames injection. The presence of openings contributed to the greater velocity at forearms, shanks and around neck, which enhanced the convective heat transfer within microclimate. Thermal radiation was the dominant heat transfer mode within the microclimate for garment with closures. On the contrary, convective heat transfer within microclimate for clothing with openings cannot be neglected.Practical implicationsThe findings provided fundamental supports for the ease and pattern design of the improved thermal protective systems, so as to realize the optimal thermal insulation of the microclimate on the garment level in the future.Originality/valueThe outcomes broaden the insights of results obtained from the mesoscale models. Different high skin temperature distribution and heat transfer modes caused by thermal environment and clothing structure provide basis for advanced thermal protective clothing design.

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