scholarly journals Зависимость нагрева стабилизированных нержавеющей сталью токоограничивающих элементов на основе ВТСП-лент второго поколения от воздействия тока и параметров теплоотвода на границе с жидким азотом

2020 ◽  
Vol 46 (1) ◽  
pp. 28
Author(s):  
С.В. Самойленков ◽  
В.И. Щербаков ◽  
Д.Р. Кумаров ◽  
Д.А. Горбунова
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Stainless Steel ◽  
Surface Area ◽  
Liquid Nitrogen ◽  
Fault Current ◽  
Current Limiting

Fault current heating of the current limiting modules made of 2G HTS tapes and stabilized with stainless steel was studied. It is demonstrated that the speed of current limiting element heating hardly depends on the degree of the stainless steel stabilization. The ways to improve the heat transfer with the help of the increase of the elements’ surface area were demonstrated with the use of a mathematical model taking into account parameters of heat transfer to liquid nitrogen.

Heat Transfer and Fragmentation During Molten-Metal/Water Interactions

1973 ◽  
Vol 95 (4) ◽  
pp. 521-527 ◽  
Author(s):  
L. C. Witte ◽  
T. J. Vyas ◽  
A. A. Gelabert
Keyword(s):  
Heat Transfer ◽  
Surface Area ◽  
Liquid Nitrogen ◽  
Molten Metal ◽  
High Speed ◽  
Vapor Film ◽  
Molten Metals ◽  
Lead Zinc ◽  
Insight Into ◽  
Rapid Transfer

Molten metals, (mercury, lead, zinc, bismuth, tin, and aluminum) were quenched in water and liquid nitrogen. High-speed photographs provide insight into the fragmentation phenomenon. The key to the vapor explosion is the very rapid transfer of heat which requires substantial surface area: fragmentation provides this necessary surface area. Prior fragmentation theories are examined in light of these experiments and are found to be inadequate. This study indicates strongly that fragmentation occurs when a sample is molten and fragmentation is a response to an external stimulus. Alternate causes of fragmentation are proposed and are predicated upon the initial collapse of a vapor film around the molten metal. The data also show that energy required to form new surface area and to displace water during the fragmentation phenomenon is not significant when compared to the energy available in a molten sample.

Experimental Research of Boiling Heat Transfer Phenomena on Metal Surface in State of Low Gravitational Acceleration Field Between 0g and 1g

2011 ◽  
Author(s):  
Eiji Nemoto ◽  
Tomohiro Saitoh
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Stainless Steel ◽  
Liquid Nitrogen ◽  
Metal Surface ◽  
Boiling Heat Transfer ◽  
Sample Surface ◽  
Gravitational Acceleration ◽  
Maximum Heat ◽  
Acceleration Field

The paper deals with the characteristics of boiling heat transfer phenomena on the metal surfaces where gravitational acceleration between 0g and 1g acts. To conduct the experiment in the field where the gravitational acceleration between 1g and 0g acted accurately, we produced the Atwood machine that was able to obtain the fixed gravitational acceleration field known by physics well. The metallic materials used by the experiment were brass, stainless steel, aluminum, copper and these materials were processed to 10mm in the diameter, and we put these samples in liquid nitrogen and experimented on the boiling phenomenon. As a result, it has been understood that there is the feature shown next in boiling heat transfer phenomena on the metal surface in gravitational acceleration field between 0g and 1g. (1) When brass, copper, stainless steel, and aluminum of the sample were put in the liquid nitrogen, the temperature differentiation coefficient on the sample surface showed the tendency to decrease in proportion to gravitational acceleration changed from 1g into 0g. (2) In boiling heat flux curve in these metals (brass, stainless steel, aluminum and copper), it was clarified for gravitational acceleration 1g to indicate maximum heat flux value qmax.

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