Laboratory Experiments on Oil-Jet Cooling of Internal Combustion Engine Pistons: Area-Average Correlation of Oil-Jet Impingement Heat Transfer

Oil-jet cooling of internal combustion engine pistons has risen in prominence with the need to improve fuel economy by increasing the power density of engines. Laboratory tests were performed on a production automotive piston under a range of conditions representative of engine conditions to develop a suitable area-average heat transfer correlation to be employed for numerical evaluation of oil-jet cooling of internal combustion engine pistons. In addition to the Reynolds and Prandtl numbers, the Nusselt number was found to be a function of the dimensionless nozzle diameter and viscosity, and a weak function of the dimensionless nozzle-to-wall spacing.