The positioning of a metal mesh between a property and a wildfire not only reduces the threat of ember attack, but can also be effective in reducing the radiation heat flux from the fire to the property. A computational technique is used to establish a view factor correlation for the object-screen-wildfire arrangement for screens consisting of woven wire, square-celled elements. The view factor between the object and fire is calculated separately for each square-celled element of the screen and the results are added. The results indicate that the average view factor between an infinite fire and an object of the same size as the square cell is only related to the porosity of screen and is independent of distance of the object from the screen (when the object is in the proximity of the mesh). The results also show the view factor is less than screen porosity, particularly at lower porosities.
Critical heat flux calculation model for tubes with twisted tapes
