Nonsteady-state radiant-conductive heat exchange in a semitransparent medium with phase transition

1987 ◽  
Vol 28 (1) ◽  
pp. 91-93 ◽  
Author(s):  
A. L. Burka ◽  
N. A. Rubtsov ◽  
N. A. Savvinova
Keyword(s):  
Phase Transition ◽  
Heat Exchange ◽  
Conductive Heat ◽  
Nonsteady State ◽  
Semitransparent Medium

scholarly journals Lecciones de mecánica de fluidos en el tratado hipocrático Sobre los flatos

2012 ◽  
pp. 13
Author(s):  
César Sierra Martín
Keyword(s):  
Phase Transition ◽  
Heat Exchange ◽  
Fluid Mechanics ◽  
Physical Laws

En el presente trabajo abordaremos el tratado hipocrático Sobre los flatos, conocido por su influencia sofista y vocación retórica. Nuestro objetivo es destacar las analogías y referencias de su autor a leyes y principios físicos como el intercambio de calor, los cambios de estado y la circulación de fluidos. Creemos que todo ello forma parte de la intención de otorgar credibilidad al discurso y a las teorías del autor.This paper is about the Hippocratic treatise On Breaths, characterized by its Sophist influence and its rhetoric vocation. The aim of the article is to highlight the similarities and the references did by the author on physical laws such as heat exchange, phase transition and fluid mechanics. In our opinion this references aimed to reinforce the speech and theories of the author.

scholarly journals Heat exchange of a roller with a particle from polymeric material when it is pressed into tissue

2019 ◽  
Vol 298 ◽  
pp. 00086
Author(s):  
Vladimir Fedyaev ◽  
Valentin Khaliulin ◽  
Marat Faskhutdinov ◽  
Alexey Belyaev ◽  
Liliya Sirotkina
Keyword(s):  
Heat Transfer ◽  
Heat Exchange ◽  
Initial Conditions ◽  
Thermal Contact ◽  
Polymer Particle ◽  
Heat Propagation ◽  
Conductive Heat ◽  
Polymer Particles ◽  
Heat Conservation ◽  
The Heat Balance

We study the heat transfer of polymer particles with a roller that presses the material of the particles into the fabric. Provided that the speed of movement of the tissue with the particles relative to the roller is small, the heat exchange of the pressed particles with the environment is not taken into account, a mathematical model of conductive heat transfer in the contacting roller, polymer particle and reinforcing fabric is proposed. This model includes heat conservation equations written with respect to average temperatures of the roller, particles, fabric, as well as boundary and initial conditions. Assuming that there is perfect thermal contact between the polymer particles and the fabric, in the direction of heat propagation the average thickness of the pressed tissue particle is small, the layer of material of particles and fabric is considered thermally thin, the temperature in it varies slightly in thickness. As a result, the initial system of three equations is reduced to one equation with respect to the temperature of the roller, which is supplemented by the corresponding boundary and initial conditions. In the case when the temperature along the radius of the roller varies along its radius linearly, the specific heat flux on the surface of the roller is estimated. After that, this expression is substituted into the heat balance equation of a thermally thin layer consisting of particle material and tissue, which is integrated after certain transformations.

Reversible Heat Exchange in the Nozzle with Water–Ice Phase Transition in Filtration of Air

2019 ◽  
Vol 28 (1) ◽  
pp. 103-113 ◽  
Author(s):  
I. V. Mezentsev ◽  
Yu. I. Aristov ◽  
N. N. Mezentseva ◽  
V. A. Mukhin
Keyword(s):  
Phase Transition ◽  
Heat Exchange ◽  
Water Ice ◽  
Ice Phase

scholarly journals Thermal conductivity of firn at Lomonosovfonna, Svalbard, derived from subsurface temperature measurements

2019 ◽  
Vol 13 (7) ◽  
pp. 1843-1859 ◽  
Author(s):  
Sergey Marchenko ◽  
Gong Cheng ◽  
Per Lötstedt ◽  
Veijo Pohjola ◽  
Rickard Pettersson ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Heat Exchange ◽  
Effective Thermal Conductivity ◽  
Vertical Profile ◽  
Systematic Errors ◽  
Conductive Heat ◽  
Glacier Surface ◽  
Optimization Routine ◽  
Subsurface Temperatures ◽  
Over Time

Abstract. Accurate description of snow and firn processes is necessary for estimating the fraction of glacier surface melt that contributes to runoff. Most processes in snow and firn are to a great extent controlled by the temperature therein and in the absence of liquid water, the temperature evolution is dominated by the conductive heat exchange. The latter is controlled by the effective thermal conductivity k. Here we reconstruct the effective thermal conductivity of firn at Lomonosovfonna, Svalbard, using an optimization routine minimizing the misfit between simulated and measured subsurface temperatures and densities. The optimized k* values in the range from 0.2 to 1.6 W (m K)−1 increase downwards and over time. The results are supported by uncertainty quantification experiments, according to which k* is most sensitive to systematic errors in empirical temperature values and their estimated depths, particularly in the lower part of the vertical profile. Compared to commonly used density-based parameterizations, our k values are consistently larger, suggesting a faster conductive heat exchange in firn.

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