Numerical studies of temperature fields in cable lines to analyze the possibility of compacting a cable channel

2014 ◽  
Vol 85 (11) ◽  
pp. 657-659 ◽  
Author(s):  
N. M. Trufanova ◽  
E. Yu. Navalikhina
2003 ◽  
Vol 125 (1) ◽  
pp. 138-145 ◽  
Author(s):  
Yuh J. Chao ◽  
X. Qi ◽  
W. Tang

In the friction stir welding (FSW) process, heat is generated by friction between the tool and the workpiece. This heat flows into the workpiece as well as the tool. The amount of heat conducted into the workpiece determines the quality of the weld, residual stress and distortion of the workpiece. The amount of the heat that flows to the tool dictates the life of the tool and the capability of the tool for the joining process. In this paper, we formulate the heat transfer of the FSW process into two boundary value problems (BVP)—a steady state BVP for the tool and a transient BVP for the workpiece. To quantify the physical values of the process the temperatures in the workpiece and the tool are measured during FSW. Using the measured transient temperature fields finite element numerical analyses were performed to determine the heat flux generated from the friction to the workpiece and the tool. Detailed temperature distributions in the workpiece and the tool are presented. Discussions relative to the FSW process are then given. In particular, the results show that (1) the majority of the heat generated from the friction, i.e., about 95%, is transferred into the workpiece and only 5% flows into the tool and (2) the fraction of the rate of plastic work dissipated as heat is about 80%.


2020 ◽  
Vol 42 ◽  
pp. e10
Author(s):  
Jean Jonathan Schuster ◽  
Áttila Leães Rodrigues ◽  
Luis Fernando Camponogara ◽  
Luis Eduardo Medeiros ◽  
Felipe Denardin Costa

Despite recent advances in understanding the physical capacity of the thermal and mechanical parameters that control or isolate the nocturnal boundary layer, these are not yet fully understood. The emergence of natural intermittence in runoff is also not a consensus in the boundary layer scientific community. Many of the studies that present numerical studies on intermittence make use of external flow, forcing that is responsible for the resurgence of turbulence. Thus, the current proposal aims to develop a numerical experiment to study the laminar-turbulent transition using computational fluid dynamics. In this case, the thermal stratification will be applied to a turbulent flow entirely generated to obtain conditions of robust stability and to reproduce an intermittent flow. The results show that when the flow regime is thoroughly turbulent, all levels are coupled by turbulence, making speed and temperature fields more homogeneous in the center of the domain. The results show that when the flow regime is completely turbulent, all levels are coupled by turbulence, making speed and temperature fields more homogeneous in the center of the domain. As a temperature gradient is introduced into the flow, the vertical levels become uncoupled, and under very stable conditions, the turbulence is wholly suppressed. While the distinction between flow regimes is evident, the transition between flow regimes occurs intermittently.


1972 ◽  
Vol 14 (2) ◽  
pp. 107-127 ◽  
Author(s):  
R. G. Brooks ◽  
S. D. Probert

The temperature fields and the transfer of heat within vertical, inclined and horizontal air layers are examined for each of three different heat transfer regimes. Experimental evidence is offered which explains the difference between the heat transfer correlations of previous investigations in which the Nusselt modulus is based on the heat flux leaving the heated wall and those in which the Nusselt number is based upon the rate at which heat is transferred to the cooled wall. It is also shown that some of the thermal boundary conditions which have generally been assumed in numerical studies are unrealistic.


2019 ◽  
Vol 111 ◽  
pp. 02018
Author(s):  
Cristiana Croitoru ◽  
Ilinca Nastase ◽  
Florin Bode ◽  
Gabriel Cojocaru

This study is a part of a larger experimental and numerical campaign intended to evaluate the influence of the turbulence intensity at the inlet of the terminal air distribution systems on the local draft sensation and thermal discomfort of ventilation users. In this paper we present preliminary results of CFD simulations using a realistic model of human body along with an experimental validation. The model is further used in a piston distribution scheme to evaluate the influence of turbulence intensity on the comfort indicators. The recorded velocity, turbulence and temperature fields allowed us to estimate the distributions of DR, PPD and PMV indexes. For the investigated case, the results indicated a direct correlation.


2016 ◽  
Vol 683 ◽  
pp. 540-547
Author(s):  
Igor V. Miroshnichenko ◽  
Mikhail A. Sheremet

Two-dimensional numerical studies were performed for investigation of the effect of thermophysical properties of solid walls on turbulent <em>convective </em>– <em>radiative </em>heat transfer in an air filled square cavity. The <em>main attention was paid to the influence of </em>thermal conductivity ratio1 ≤ κ1, 2 ≤ 1000 and an emissivity of internal surfaces of the solid walls 0 £ < 1 on velocity and temperature fields. Numerical results were obtained by means of the finite difference method. The effect of the governing parameters on the average Nusselt number has been defined. The obtained results provide better technical support for development and research of energy-efficient building materials


2020 ◽  
Vol 1 (23) ◽  
Author(s):  
Sergey Gridnev ◽  
Igor Podlesnykh ◽  
Aleksandr Rezunov ◽  
Yuri Skalko

The article studies the effect of solar radiation at different seasons on the mode of deformation (MD) of a span structure with an orthotropic plate. The temperature fields of the elements of the structure were measured during daylight hours at different times of year at various air temperatures and sun positions. Cases were identified in which it is necessary to clarify the temperature values of the asphalt concrete road surfacing and the main beams obtained using a non-contact pyrometer, and by measuring the temperature with a contact thermometer. During the year the elements of the span are in a wide temperature range. Using the developed finite element model of the span, taking into account the layers of road surfacing, the MD calculations were performed for each case of exposure to solar radiation according to the corrected results of field measurements. An analysis of the results of numerical studies allows us to conclude that diurnal and seasonal temperature fluctuations create significant additional stresses in the span, which should be taken into account when calculating the MD of spans of road bridges.


Author(s):  
A. Baronnet ◽  
M. Amouric

The origin of mica polytypes has long been a challenging problem for crystal- lographers, mineralogists and petrologists. From the petrological point of view, interest in this field arose from the potential use of layer stacking data to furnish further informations about equilibrium and/or kinetic conditions prevailing during the crystallization of the widespread mica-bearing rocks. From the compilation of previous experimental works dealing with the occurrence domains of the various mica "polymorphs" (1Mr, 1M, 2M1, 2M2 and 3T) within water-pressure vs temperature fields, it became clear that most of these modifications should be considered as metastable for a fixed mica species. Furthermore, the natural occurrence of long-period (or complex) polytypes could not be accounted for by phase considerations. This highlighted the need of a more detailed kinetic approach of the problem and, in particular, of the role growth mechanisms of basal faces could play in this crystallographic phenomenon.


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