Ignition of combustible fluids by heated surfaces

Industrial machinery fires are commonly caused bq,flammable operating fluid s leaking onto hot machinery surfaces. This paper discusses doctoral resear ch currently underway, to identify the dominant fundamental mechanisms cont rolling 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 a ble to predict the minimum surface ignition temperature for a given set of lu id and surface properties, more accurately define safe operating boundar ies of equipment to mitigate fire events, and suggest optimal designs to wi den the safe operating envelope. As a result of recent analyses, a surface modification technique has been proposed to use a pattern of micro-cavities , sired to prevent fluid seepage, on the exterior of the heated surface to reduce the heat transfer from surface to liquid (due to reduced direct cont act), and inhibit the formation of superheated vapor films. This behavior c ould increase the temperatures necessary for ignition, permitting! a wider range of safe operating conditions.