Diffusion, rotation, and lagging behavior of a thermoelastic micropolar medium with voids and temperature gradient under mechanical pressure

2021 ◽  
pp. 1-20
Author(s):  
Mohamed I. M. Hilal
Keyword(s):  
Temperature Gradient ◽  
Mechanical Pressure ◽  
Micropolar Medium

Zur phänomenologischen Beschreibung der Thermoosmose Überführungswärme und thermomechanischer Homogeneffekt

1965 ◽  
Vol 20 (11) ◽  
pp. 1386-1390
Author(s):  
P. Läuger
Keyword(s):  
Temperature Gradient ◽  
Pressure Difference ◽  
Simple Relation ◽  
Irreversible Processes ◽  
Constant Composition ◽  
Discontinuous System ◽  
Mechanical Pressure ◽  
Liquid Phases ◽  
Temperature And Pressure ◽  
Mechanical Pressure Difference

In a membrane separating two identical liquid phases a temperature gradient მT/მx gives rise not only to a flow of heat but also, in general, to a flow of matter. If, conversily, (მT/მx) =0 and liquid is transported through the membrane under a small mechanical pressure difference, heat is liberated or consumed at the surfaces of the membrane. In the thermodynamic theory of irreversible processes these thermomechanical effects are usually treated by considering the membrane simply as a boundary between two homogenous phases. In the present paper it is shown that, by applying the theory of irreversible processes in continuous media, a somewhat more complete description of the thermomechanical phenomena can be achieved. In this treatment the membrane is considered as a separate phase with continuously varying temperature and pressure. This leads at first to the well-known relation between the heat of transfer and the thermomechanical pressure difference which is also obtained in the theory of the discontinuous system. In addition, the existence of a new thermomechanical heat effect can be predicted which occurs in a phase of constant composition in which a temperature gradient მT/მx and a flow of matter (Φm) are simultaneously present. This thermomechanical heat ϰ Φm (მT/მx) is a direct analogue of the Thomson heat of thermoelectricity (i. e. the heat liberated by an electric current in a non-isothermal conductor of constant composition) . It is further shown that a simple relation exists between the coefficient ϰ and the temperature dependence of the heat of transfer.

Technical Note. Influence of Material Used for the Regenerator on the Properties of a Thermoacoustic Heat Pump

2013 ◽  
Vol 38 (4) ◽  
pp. 565-570 ◽  
Author(s):  
Bartłomiej Kruk
Keyword(s):  
Heat Transfer ◽  
Temperature Gradient ◽  
Acoustic Wave ◽  
Heat Pump ◽  
Sound Wave ◽  
Heat Exchangers ◽  
Heat Pumps ◽  
Technical Note ◽  
New Materials ◽  
Modern Technologies

Abstract Research in termoacoustics began with the observation of the heat transfer between gas and solids. Using this interaction the intense sound wave could be applied to create engines and heat pumps. The most important part of thermoacoustic devices is a regenerator, where press of conversion of sound energy into thermal or vice versa takes place. In a heat pump the acoustic wave produces the temperature difference at the two ends of the regenerator. The aim of the paper is to find the influence of the material used for the construction of a regenerator on the properties of a thermoacoustic heat pump. Modern technologies allow us to create new materials with physical properties necessary to increase the temperature gradient on the heat exchangers. The aim of this paper is to create a regenerator which strongly improves the efficiency of the heat pump.

Field distribution in polymeric MV-HVDC model cable under temperature gradient. Simulation and space charge measurements

2014 ◽  
Vol 17 (5-6) ◽  
pp. 307-325 ◽  
Author(s):  
Thi Thu Nga Vu ◽  
Gilbert Teyssedre ◽  
Bertrand Vissouvandin ◽  
Séverine Le Roy ◽  
Christian Laurent ◽  
...  
Keyword(s):  
Temperature Gradient ◽  
Space Charge ◽  
Field Distribution

SIMULATION OF THE CURRENT-VOLTAGE CHARACTERISTICS OF SOLAR BATTERIES WITH CONSIDERING DECREASE OF LIGHTING DUE TO THE INFLUENCE OF JETS OF THE ELECTRIC PROPULSION

2019 ◽  
pp. 56-64
Author(s):  
Ya.N. MIGUNOV ◽  
V.V. ONUFRIEV
Keyword(s):  
Solar Cells ◽  
Temperature Gradient ◽  
Electric Propulsion ◽  
Protective Coatings ◽  
Rocket Engine ◽  
Solar Array ◽  
Rocket Engines ◽  
Lighting Conditions ◽  
Main Equation ◽  
Voltage Current Characteristic

A model for calculating the voltage-current characteristic of a solar array in the presence of a temperature gradient by its photovoltaic converters and their variable illumination due to possible pollution under the action of space factors, including operation of electric rocket engines, is described. The model is based on the main equation of a solar cell. In this case both a one-dimensional and a two-dimensional temperature gradients are taken into account. The principles of constructing a model are given, and the initial data selection is made. To simulate the lighting conditions of the solar array such a concept as effective illumination is used, i.e. the density of the radiation flux which falls on photovoltaic converters passing through the protective coatings. The features of simulation of the temperature distribution in the solar array and the effective illumination of its surface in cases of parallel, serial and mixed switching of solar cells are described. The calculation procedures and examples of solar cells are given. The construction of the model in universal mathematical package Mathcad is described. Some simulation results are discussed. Key words: solar array, mathematical simulation, illumination, temperature gradient, electric rocket engine, spacecraft, Mathcad.

EFFECTS OF TEMPERATURE GRADIENT ON LAMELLAR ORIENTATIONS OF DIRECTIONAL SOLIDIFIED TiAl--BASED ALLOY

2011 ◽  
Vol 46 (10) ◽  
pp. 1223-1229 ◽  
Author(s):  
Zhixia XIAO ◽  
Lijing ZHENG ◽  
Lili YANG ◽  
Jie YAN ◽  
Hu ZHANG
Keyword(s):  
Temperature Gradient ◽  
Effects Of Temperature
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