Ignition of combustible fluids by heated surfaces

Abstract

AbstractIndustrial machinery fires are commonly caused by flammable operating fluids leaking onto hot machinery surfaces. This paper discusses doctoral research currently underway to identify the dominant fundamental mechanisms controlling the overall ignition process of combustible liquid stream‐fed pools impinging on heated surfaces. Experiments are now underway to characterize these processes, via modeling and the use of dimensional analysis, to be able to predict the minimum surface ignition temperature for a given set of fluid and surface properties, more accurately define safe operating boundaries of equipment to mitigate fire events, and suggest optimal designs to widen the safe operating envelope. As a result of recent analyses, a surface modification technique has been proposed to use a pattern of micro‐cavities, sized to prevent fluid seepage, on the exterior of the heated surface to reduce the heat transfer from surface to liquid (due to reduced direct contact), and inhibit the formation of superheated vapor films. This behavior could increase the temperatures necessary for ignition, permit‐ting a wider range of safe operating conditions.