Effect of the mass fraction of a binder in a thermal protective coating on the heat and mass exchange with a high-enthalpy gas flow

1998 ◽  
Vol 34 (6) ◽  
pp. 644-650 ◽  
Author(s):  
V. I. Zinchenko ◽  
V. V. Nesmelov ◽  
A. S. Yakimov ◽  
G. F. Kostin
Author(s):  
E.K. Aliev ◽  
V.V. Volodin ◽  
V.V. Golub ◽  
A.Yu. Mikushkin ◽  
G.G. Timerbaev ◽  
...  

The paper focuses on comparative studies of heat and mass transfer and hydraulic characteristics of two structured packings which provide heat and mass transfer of contacting media in the film flow of liquid Mellapak 250.X and with fluid dispersion in the gas volume PVN.22. The experiments were carried out in a heat-mass exchange column of 400 mm in diameter and of 1 m in height of a packed bed. The method of evaporative cooling of water in the air flow was adapted to obtain heat and mass exchange characteristics of packed contact devices. Findings of research show the effect of irrigation density and gas flow on heat and mass transfer and hydraulic characteristics of packings which provide heat and mass transfer of contacting media in film and droplet flows. A criterion for estimating the efficiency of contact devices is proposed.


Author(s):  
M. Kh. Gadzhiev ◽  
A. S. Tyuftyaev ◽  
Yu. M. Kulikov ◽  
M. A. Sargsyan ◽  
D. I. Yusupov ◽  
...  

Low-temperature plasma is used in metallurgy for steel alloying by nitrogen, deoxidization of magnetic alloys, obtaining of steels with particularly low carbon content, metal cleaning of nonmetallic inclusions, desulfurization and other refining processes. The wide application of those technologies is restrained by absence of reliable generators of low-temperature plasma (GLP) with sufficient resource of continuous operation. As a result of studies, a universal generator of high-enthalpy plasma jet of various working gases was created. The generator has expanding channel of the output electrode with an efficiency of ~60 % for argon working gas and ~80% for nitrogen and air. It was shown that the developed generator of low-temperature plasma ensures formation of a weakly diverging (2α = 12°) plasma jet with a diameter D = 5–12 mm, an enthalpy of 5–50 kJ/g and a mass average temperature of 5–10 kK, at a full electric power of the arc discharge of 5–50 kW and a plasma-forming gas flow rate of 1–3 g/s. Results of the study of propane additions to the plasma-forming gas effect on the state of cathodes with inserts made of pure tungsten, lanthanum tungsten, and hafnium presented. It was shown that a small propane addition (1%) to the plasma-forming gas, results in reducing effect of the insert material. Study of the GLP operation at arc current 100A with addition to the working gas nitrogen maximum possible volume of propane, which don’t disturb stability of arc showed that for the developed plasma generator at the nitrogen flow rate ~0,45 g/s, the propane flow rate was ~0,33 g/s (not more than ~73 % of the plasma-forming gas). The created high-resource GLP with changeable electrodes enables to obtain at the exit a high-enthalpy plasma flow of various gases (argon, nitrogen, air) and can be a prototype of more powerful plasmotrons of various technological application, in particular for plasma metallurgy.


2018 ◽  
Vol 6 (1 (96)) ◽  
pp. 47-54 ◽  
Author(s):  
Aleksey Zagorulko ◽  
Andrii Zahorulko ◽  
Kateryna Kasabova ◽  
Vitalii Chervonyi ◽  
Oleksandr Omelchenko ◽  
...  

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