Influence of transverse temperature gradient on the propagation of triple flames in porous channels

2018 ◽  
Vol 76 (2) ◽  
pp. 406-418 ◽  
Author(s):  
Faisal Al-Malki
2020 ◽  
Vol 10 (6) ◽  
pp. 1980 ◽  
Author(s):  
Lei Zhao ◽  
Ling-Yu Zhou ◽  
Guang-Chao Zhang ◽  
Tian-Yu Wei ◽  
Akim D. Mahunon ◽  
...  

To study the temperature distribution in the China Railway Track System Type II ballastless slab track on a high-speed railway (HSR) bridge, a 1:4 scaled specimen of a simply-supported concrete box girder bridge with a ballastless track was constructed in laboratory. Through a rapid, extreme high temperature test in winter and a conventional high temperature test in summer, the temperature distribution laws in the track on the HSR bridge were studied, and the vertical and transverse temperature distribution trend was suggested for the track. Firstly, the extreme high temperature test results showed that the vertical temperature and the vertical temperature difference distribution in the track on HSR bridge were all nonlinear with three stages. Secondly, the extreme high temperature test showed that the transverse temperature distribution in the track was of quadratic parabolic nonlinear form, and the transverse temperature gradient in the bottom base was significantly higher than that of the other layers of the track. Thirdly, the three-dimensional temperature distribution in the track on HSR bridge was a nonlinear, three-stage surface. Furthermore, similar regularities were also obtained in the conventional high temperature test, in which the temperature span ranges were different from those of the extreme high temperature test. In addition, the conventional high temperature test also showed that under the natural environment conditions, the internal temperature gradient in the track layers changed periodically (over a period of 24 h).


Author(s):  
А.В. Горбатюк ◽  
Б.В. Иванов

AbstractThe effects of a transverse temperature gradient in reversively switched-on dynistors have been studied. Taking into account these effects is important for high-voltage frequency dynistor assemblies because of the problems of a distributed cooling of the devices. A simulation description is given for the spatial dynamics of charges and heat in dynistor chips in switching of repeated current pulses. An estimation method is suggested for calculating the maximum repetition frequency coordinated with the heatsink heatsink cooling power.


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