4,750 research outputs found

    Transpiration cooled turbine blade manufactured from wires Patent

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    Transpiration cooled turbine blade made from metallic or ceramic wire

    Thermal analysis of cathode and anode regimes of an MPD arc Summary report, Jun. 1965 - Jan. 1967

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    Thermal analysis of anode and cathode heat transfer in magnetohydrodynamic electric arc

    Solar-Thermal Energy Conversion

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    The fact that our conventional fuel resources are finite and will be exhausted some time in the future gives impetus to a consideration of solar radiation for conversion into heat or electric power. The characteristics of the solar radiation - that the enrgy flux density is small and that it arrives intermittently on the ground of our glove has to be considered in any system utilizing this energy source. For home heating parts of the roof offer a sufficiently large area, for electric power production areas of some km2 are required to collect a sufficient amount of energy. Optical concentration, thermal collection by a fluid and electric collection are generally used in series. A crucial element in any scheme is the design of the solar collector. The conditions Imposed by the specific application and the possibilities to obtain high collection efficiencies are Investigated. Recent developments in thin film technology have provided means for improvement of the absorber and the glass envelope of the collector, and have brought solar thermal plants closer to a condition where it is competitive with other energy sources

    Measurement of Prandtl number and thermal conductivity Summary report

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    Prandtl numbers and thermal conductivity of air, argon, and hydrocarbon fuel combustion product

    Intermediate valence behavior in CeCo9Si4

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    The novel ternary compound CeCo9_9Si4_4 has been studied by means of specific heat, magnetisation, and transport measurements. Single crystal X-ray Rietveld refinements reveal a fully ordered distribution of Ce, Co and Si atoms with the tetragonal space group I4/mcm isostructural with other RCo9Si4. The smaller lattice constants of CeCo9Si4 in comparison with the trend established by other RCo9Si4 is indicative for intermediate valence of cerium. While RCo9Si4 with R= Pr, .. Tb, and Y show ferromagnetism and LaCo9Si4 is nearly ferromagnetic, CeCo9Si4 remains paramagnetic even in external fields as large as 40 T, though its electronic specific heat coefficient (g~190 mJ/molK^2) is of similar magnitude as that of metamagnetic LaCo9Si4 and weakly ferromagnetic YCo9Si4.Comment: 2 pages, 3 figures, submitted to SCES 0

    Comparison of effectiveness of convection-, transpiration-, and film-cooling methods with air as coolant

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    Various parts of aircraft propulsion engines that are in contact with hot gases often require cooling. Transpiration and film cooling, new methods that supposedly utilize cooling air more effectively than conventional convection cooling, have already been proposed. This report presents material necessary for a comparison of the cooling requirements of these three methods. Correlations that are regarded by the authors as the most reliable today are employed in evaluating each of the cooling processes. Calculations for the special case in which the gas velocity is constant along the cooled wall (flat plate) are presented. The calculations reveal that a comparison of the three cooling processes can be made on quite a general basis. The superiority of transpiration cooling is clearly shown for both laminar and turbulent flow. This superiority is reduced when the effects of radiation are included; for gas-turbine blades, however, there is evidence indicating that radiation may be neglected

    Analysis of turbulent free-convection boundary layer on flat plate

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    A calculation was made for the flow and heat transfer in the turbulent free-convection boundary layer on a vertical flat plate. Formulas for the heat-transfer coefficient, boundary layer thickness, and the maximum velocity in the boundary layer were obtained

    Experimental investigation of free-convection heat transfer in vertical tube at large Grashof numbers / E. R. G. Eckert, A. J. Diaguila

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    Local free-convection heat-transfer coefficients and temperature fields in the turbulent flow range were obtained within a vertical, stationary tube closed at the boom, heated along its walls, and having a length-to-diameter ratio of 5. Convective heat-transfer coefficients were correlated by the general relations for free-convection heat transfer. These coefficients, converted to dimensionless Nusselt numbers were 35 percent below known relations for vertical flat plates. Air temperature measurements within the tube indicated a thin boundary layer along the heated wall surface and unstable conditions in the air flow
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