An investigation into the flow and heat transfer characteristics of an open cooling gallery in piston

A simulation study on the flow and heat transfer characteristics of an open cooling gallery of piston is conducted by using moving mesh technique of software FLUENT and Volume of Fluid model for multi-phase flow to reveal the rules of the oil trap ratio, oil fill ratio and heat transfer coefficient changed with speed and cooling oil flow. The results show that the oil trap ratio is about 60%~80%; the oil fill ratio highly depends on engine speed and oil flow rate; the cycle-average heat transfer coefficient of oil gallery wall rapidly increases with the rise of speed; too high or too low a oil fill ratio may lead to the worsening of heat transfer performance and a oil fill ratio of some 50% can reduce required oil flow rate of cooling nozzle while assuring the effects of shaking heat transfer of piston.