Surface Emissivity Effect on the Performance of Composite Metal Foam against Torch Fire Environment

Abstract

Abstract. According to the US Department of Transportation (DOT), there are millions of liters of hazardous materials (HAZMATS) transported each year via railroad. This has translated to stringent safety measures taken to alleviate the effects of accidents involving tank cars carrying these HAZMATs. One of such measures is in the creation of the thermal protection system of tank cars in which the tank car must have sufficient thermal resistance when subjected to a simulated pool fire for 100 mins and a torch fire for 30 mins without its back plate temperature exceeding 427 ºC at any point of time. This requires a suitable material as a thermal blanket and insulation in tank car lining. Steel-steel composite metal foam (S-S CMF) is a novel metal foam with unique properties of high strength to density ratio, lightweight, and high energy absorption. It consists of metallic hollow spheres that are closely packed within a metal matrix. The large percentage of air within the hollow spheres provide both lightweight and insulating effects for CMF. S-S CMF is being investigated using the standard torch fire test requirement to determine its suitability as a material for tank car thermal protection. This is accomplished by developing a numerical model using the Fire dynamics simulator (FDS) as a form of validation for experimental work done. To properly evaluate this, there are various thermal properties of S-S CMF that need to be established for predicting CMF’s thermal response. Surface emissivity has been a challenging property to evaluate and hence this study focuses on developing an experimental and numerical procedure in evaluating this property for composite materials such as CMF. Preliminary data shows an acceptable prediction of emissivity, which will be applied to the FDS model for the torch fire test.