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Analysis of spray-wall interaction is a major issue in the study of the combustion process in DI diesel engines. Along with spray characteristics, the investigation of impinging sprays and of liquid wall film development is fundamental for predicting the mixture formation. Simulations of these phenomena for diesel sprays need to be validated and improved; nevertheless they can extend and complement experimental measurements. In this paper the wall film thickness for impinging sprays was investigated by evaluating the heat transfer across a temperature controlled wall. In fact, heat transfer is significantly affected by the wall film thickness, and both experiments and simulations were carried out to correlate the wall temperature variations and film height. The numerical simulations were carried out using the STAR-CD and the KIVA-3V, rel. 2, codes.

Heat transfer from impinging sprays in direct injected diesel engines has been found to influence the rate of heat release and the formation of emissions. The use of multiple injections may also affect heat transfer. The objective of this work is to study heat transfer between the wall and the spray, and how the surface temperature of the wall affects spray behaviour in single and split injections. Two different diesel fuels were used in the experiments, noteworthy is that the diesel fuel had a higher radial penetration rate than the Idea fuel at evaporating conditions but not at non-evaporating conditions. The wall temperature has no measurable influence on radial penetration but does have a significant influence on the heat transfer.