Physics

  2010 AUG 31 - (VerticalNews.com) -- According to a study from Prince George, Canada, "Both two-dimensional and three-dimensional numerical simulations of the turbulent flow through a staggered tube bundle are presented. The primary aim of the present study is to search for a turbulent model that could serve as an engineering design tool at a relatively low computational cost."

  "In the present study, the performances of the Spalart-Allmaras model, the k-epsilon model, and large eddy simulation are evaluated by comparing their simulation results against experimental measurements. The turbulence models are assessed mainly based on their ability to resolve time-dependent features of the flow related to vortex shedding. Simulations are performed at a Reynolds number of 9300," wrote Y.Q. Wang and colleagues ...read more

  2010 AUG 31 - (VerticalNews.com) -- According to recent research published in the Journal of Thermophysics and Heat Transfer, "Experimental studies are conducted to investigate the effect of mist on the spray heat transfer in the cooling of a low-carbon steel cylindrical surface heated to the nucleate boiling temperature range. Multiple tests are performed to investigate the effect of the liquid mass flux. liquid-to-air loading. spray speed, and droplet size on the spray heat transfer along the circumference of the annulus cylinder. ...read more

  2010 AUG 31 - (VerticalNews.com) -- According to recent research from Stuttgart, Germany, "HEATS is a layout tool for the determination of transient wall heat flux to a transpiration-cooled parallel fiat plate under laminar or turbulent now conditions. The method is based on heat balances between wall material, transpired coolant, and surrounding hot gas."

  "It is introduced here with particular focus on a reentry mission. The investigation of transpiration cooling necessitates considering the entire flight trajectory. Because of long calculation times, computational fluid dynamics tools cannot be used. The calculation of wall temperatures of an entire trajectory with HEATS takes less than five minutes, which offers the possibility of sensitivity analyses, e.g., of coolant mass flow rate. The results presented within this paper are compared with cooling experiments under laminar flow and a computational fluid dynamics solution of one trajectory point for the second Sharp-Edge Flight Experiment trajectory for turbulent flow. The values compare well with deviations of the wall temperature below 10% and deviations of heat flux below 18%. The investigation of coolant mass flow rates by means of HEATS show that for the entire second Sharp," wrote H. Bohrk and colleagues ...read more