Technology

  2010 AUG 31 - (VerticalNews.com) -- According to recent research from Hamilton, Canada, "The effect of pulsed electric fields on two-phase flow patterns, heat transfer and pressure drop in horizontal tube side convective condensation was investigated. Experiments were performed for an applied pulse voltage of 8 kV at pulse repetition rates in the range of 0.5 Hz-1.5 kHz and duty cycles of 25%, 50% and 75%."

  "Three mass fluxes of 55,100, and 150 kg/m(2) s were tested with an average vapour quality of 45% which corresponds to an initially stratified flow. The voltage was applied through a central electrode along the centerline of the tube. Changing the pulse repetition rate and duty cycle results in different flow patterns and therefore in different values of heat transfer and pressure drop. For a given mass flux, the heat transfer enhancement due to the applied voltage decreased with the pulse repetition rate and reached a plateau," wrote H. Sadek and colleagues, McMaster University ...read more

  2010 AUG 31 - (VerticalNews.com) -- "Anodizing technique has been recognized as an efficient way to grow the well-ordered oxide nano-structures on metal substrate. In the present experimental study, the nucleate pool boiling heat transfer coefficient and long-term performance of nano-porous surface fabricated by the cost-effective and simple anodizing technique were investigated with water," researchers in the United States report ...read more

  2010 AUG 31 - (VerticalNews.com) -- "Using a typical shear cell arrangement, the degree of accuracy attained in the determination of the interdiffusion coefficients at low and moderate thermal and solutal Rayleigh numbers is analyzed here," scientists in Barcelona, Spain report.

  "It is concluded that, despite the marked directionality of these Fickian processes, thermal convective contamination is always negligible in real experiments but solutal convective contamination can be important even for moderate values of the solutal Rayleigh number," wrote X. Ruiz and colleagues ...read more