Technology

  2010 MAR 16 - (VerticalNews.com) -- "We consider the steady state, viscous, incompressible two-dimensional magneto hydrodynamic flow of an electrically conducting power law fluid over a vertical stretching sheet The stretching of the surface velocity and the prescribed surface temperature are assumed to vary linearly with the distance from the slit The coupled partial differential equations governing the flow and heat transfer are transformed into non-linear coupled ordinary differential equations by a similarity transformation The transformed boundary layer equations are solved numerically by Keller-Box method for several sets of values of the parameters governing the flow and heat transfer," scientists in the United States report ...read more

  2010 MAR 16 - (VerticalNews.com) -- According to recent research from the United States, "In structural fire engineering, it is well-known that the radiative heat exchange in unprotected steel I-section is attenuated due to geometric effect."

  "An analytical approach to formulate the geometric effect by employing view factors is presented in this paper for concave structures in general In particular, the exact solution is extended to predict the net radiation flux and the temperature evolution for unprotected steel I-sections in fire. which are fully characterized by the I-section aspect (width-to-depth) ratio. The proposed method is validated by comparison to the conventional model in Eurocode 3. as well as to experimental investigations," wrote Z.H. Wang and colleagues, Princeton University ...read more

  2010 MAR 16 - (VerticalNews.com) -- "Mixed convection in a square enclosure with a rotating cylinder centered within it is numerically studied. Depending on the rotation of the cylinder, the natural and forced convection effects can be combined or opposite," researchers in Aveiro, Portugal report.

  "However, due to the complex flow structure assumed by the flow, in some conditions the combined effects do not lead to the maximum overall heat transfer crossing the enclosure. The rotating cylinder participates on both the conductive and convective heat transfer processes, and exchanges heat with the fluid naturally, without imposition of a thermal condition at its surface. It is explored the influence of the cylinder through its radius, rotating velocity, thermal conductivity and thermal capacity on the resulting mixed convection problem. Thermal field is visualized using the isotherms, the flow structure is visualized through the streamlines, and the heat transfer process is visualized through the heat-lines. For the first time, these visualization tools are applied to a moving solid. The overall thermal performance of the enclosure is analyzed through the overall Nusselt number," wrote V.A.F. Costa and colleagues, University of Aveiro ...read more