Ignition of pine needle fuel bed by the coupled effects of a hot metal particle and thermal radiation

In the Study of small metal particles the shape is a very Important parameter. Using electron microscopy Ino and Owaga(l) have studied the shape of twinned particles of gold. In that work electron diffraction and contrast (dark field) experiments were used to produce models of a crystal particle. In this work we report a method which can give direct information about the shape of an small metal particle in the amstrong- size range with high resolution. The diffraction pattern of a sample containing small metal particles contains in general several systematic and non- systematic reflections and a two-beam condition can not be used in practice. However a N-beam condition produces a reduced extinction distance. On the other hand if a beam is out of the bragg condition the effective extinction distance is even more reduced.

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Increase of desulphurization potential of technological systems of hot metal injection desulphurization by various reagents

Ferrous Metallurgy Bulletin of Scientific Technical and Economic Information ◽

10.32339/0135-5910-2019-11-1237-1243 ◽

2019 ◽

Vol 75 (11) ◽

pp. 1237-1243

Author(s):

A. F. Shevchenko ◽

I. A. Manachin ◽

B. V. Dvoskin ◽

A. S. Vergun ◽

S. A. Shevchenko ◽

...

Keyword(s):

Technological Systems ◽

Hot Metal

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Review of methods of slag removal from melt surface in hot metal and steel ladles

Ferrous Metallurgy Bulletin of Scientific Technical and Economic Information ◽

10.32339/0135-5910-2020-12-1243-1252 ◽

2020 ◽

Vol 76 (12) ◽

pp. 1243-1252

Author(s):

B. A. Sivak ◽

A. V. Protasov ◽

L. A. Smirnov

Keyword(s):

Settling Tank ◽

Necessary Condition ◽

Hot Metal ◽

Slag Removal ◽

Production Scale ◽

Technical Parameters ◽

Ecological Requirements ◽

The Usa ◽

Work Done ◽

Technological Methods

The removal of slag from melt surface of hot metal and steel ladles is a necessary condition to provide a deep desulphurization and dephosphorization of hot metal and steel in the process of their processing. A review of methods of slag skimming presented, mainly based on slag mechanical shoveling and its removal out of ladles by vacuum sucking. It was shown, that manipulators design for the slag skimming working instrument moving depends on the production scale, mass of the processed heats, amount and properties of the slag to be removed, production process intensity and ecological requirements. Peculiarities of designs and technical parameters of machines for slag skimming presented, designed by Irkutsk plant of heavy machinery, Scientific and Production Enterprise n.a. M.I. Platov, VNIIMETMASH, Kuznetsk and Novolipetsk steel plants. Technological methods of control of slag composition and physical properties considered, first of all of viscosity and fluidity, which have significant effect on selection of a method of slag skimming. Advantages and drawbacks of actions, aimed at more complete slag removal from metal surface by a scraper noted including bath blowing off by an inert gas, liquid slag tapping into am intermediate settling tank following its removal into a slag bowl. In case of satisfactory fluidity it is possible to slag removal by vacuum sucking, which at the same time promoted the melt degassing. Work done in this area abroad noted. Methods of vacuum slag removal developed in the USA and Japan described.

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Characterizing the convective heat exchange with plastic shading nets under natural arid conditions

International Journal of Energy Technology ◽

10.32438//ijet.11415 ◽

2019 ◽

pp. 11-20

Author(s):

Ahmed M Abdel-Ghanya ◽

Ibrahim M Al-Helal

Keyword(s):

Wind Speed ◽

Thermal Radiation ◽

Convective Heat ◽

Convective Heat Transfer Coefficient ◽

Convective Heat Exchange ◽

Radiative Properties ◽

Wooden Frame ◽

Arid Conditions ◽

Air Temperatures ◽

Radiation Fluxes

Plastic nets are extensively used for shading purposes in arid regions such as in the Arabian Peninsula. Quantifying the convection exchange with shading net and understanding the mechanisms (free, mixed and forced) of convection are essential for analyzing energy exchange with shading nets. Unlike solar and thermal radiation, the convective energy, convective heat transfer coefficient and the nature of convection have never been theoretically estimated or experimentally measured for plastic nets under arid conditions. In this study, the convected heat exchanges with different plastic nets were quantified based on an energy balance applied to the nets under outdoor natural conditions. Therefore, each net was tacked onto a wooden frame, fixed horizontally at 1.5-m height over the floor. The downward and upward solar and thermal radiation fluxes were measured below and above each net on sunny days; also the wind speed over the net, and the net and air temperatures were measured, simultaneously. Nets with different porosities, colors and texture structures were used for the study. The short and long wave’s radiative properties of the nets were pre-determined in previous studies to be used. Re and Gr numbers were determined and used to characterize the convection mechanism over each net. The results showed that forced and mixed convection are the dominant modes existing over the nets during most of the day and night times. The nature of convection over nets depends mainly on the wind speed, net-air temperature difference and texture shape of the net rather than its color and its porosity.

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