1,721,041 research outputs found
FINITE DIFFERENCES SOLUTION OF THREE PHASES STEFAN PROBLEM WITH HIGH POWER INPUT
No full textThe numerical solution of a one dimensional, three-phases Stefan problem with a low Stefan number is presented. Joule heating and thermal radiation are demonstrated to be negligible compared to the high power input. The Front Tracking Method is used along with a second order Lagrangian interpolation of the temperature profile near the moving surface defined by the location of the phase change. Results are compared with analytical, numerical and experimental solutions available in literature
Experiments on convective heat transfer on air-flows at low Reynolds number through wavy and grooved channels
No full textHeat transfer measurements by IR thermography over enhanced surfaces with skewed ribs
No full textThis paper presents the experimental results on heat transfer characteristics of air forced convection over not-thin plates with transverse and skewed ribs; data are obtained by means of infrared thermography. Compari¬sons of heat transfer distributions for ribbed plates with data over a flat plate suggest the following observations. The periodic development of the boundary layer is very well displayed by the local distribution of the convective heat transfer coefficient; for both enhanced surfaces, the average Nusselt number shows the same dependence on the Reynolds number than the flat plate; the en¬hancement factor is about 1.4 for both ribbed configura¬tion, without appreciable differences between them
APPLICATION OF THE ENHANCED SELECTIVE IONIZATION METHOD TO SILICON PRODUCTION
No full textPresent productions method of high graded pure silicon for electronics purposes involves usage of large quantities of energy, water and chemicals. The possibility to directly separate silica into its constituents with a single step would provide benefits in terms of energy consumption, logistics and environmental impact. This separation is feasible if performed by electromagnetic means on ionized silica and taking advantage of the ionization gap between oxygen and silicon, a process that can be called Enhanced Selective Ionization. In this paper the energetic feasibility of a direct separation of silica using the Enhanced Selective Ionization Method is evaluated in its energetic requirements and conversion yields. The preliminary configuration of a demonstrator devoted to demonstrate the concept is presented. The main functional parts are presented along with the respective power budget. For each part analytical and numerical allow to calculate a global energy cost per unit of silicon, which is compared with traditional production processes
Promozione dello scambio termico in convezione forzata monofase in canali mediante superfici corrugate
No full textPromozione dell'ebollizione e della condensazione in convezione forzata di fluidi frigorigeni
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POWER DISSIPATION IN HEAVY METALS RECOVERY FROM INCINERATOR ASHES
No full textUnder controlled conditions waste-to-energy plants are very useful systems to dispose solid wastes in combination with energy production. For common urban wastes, hence excluding special wastes, the incineration products are fly and heavy ashes where heavy metals are concentrated due to their impossibility to be vaporized. Those metals are usually lost because up to now the common ashes disposal methods have been cement or clay inertization or simple ashes storage in safe places. In order to recover those otherwise lost valuable and useful heavy metals we present the concept of an electromagnetic device able to separate and collect the different atomic species. The proposed device is essentially composed by an atomization stage followed by a separation one. The former atomizes and ionizes ash components allowing the second stage to perform separation of the desired metals by means of an electromagnetic field. Power dissipation represents one of the major issues of such devices due to the high power required to perform species separation. In this paper the major power sources and losses are also identified
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