Numerical simulation of oscillating heat transfer characteristics in cavity partly filled with cooling liquid

Oscillating heat transfer has been widely used in engine pistons and valves, but the mechanism of heat transport is still not clearly understood, so the design of liquid cooled pistons and valves is mostly based on empirical knowledge and it is difficult to achieve appropriate heat transfer rate. In this study, a numerical simulation on oscillating heat transfer characteristics in a cavity partly filled with cooling liquid was performed by using CFD dynamic mesh method and volume of fluid (VOF) model. The relations of heat transfer coefficient to the speed and stroke of piston and fill ratio of liquid were obtained. The results indicate that the oscillation enhances the heat transfer significantly. The rotation speed is the major factor affecting heat transfer, and the heat transfer enhancement is reinforced with the increase of rotation speed and piston of stroke. When the fill ratio range of liquid is 30%-60%, the enhancement of heat transfer is remarkable, otherwise the effect of enhancement is unsatisfactory. The results are helpful to the design of pistons and valves.