The gas-liquid two-phase flow in reciprocating enclosure with piston cooling gallery application

With the specific power of diesel engines steadily advancing, heat removal from the piston has become a determining factor to ensure engine reliability and durability of engines. However, piston head complex structure makes it very difficult to accurately capture the flow and heat transfer processes of cooling engine oil within the piston gallery. The current study used high-speed photography to obtain periodic interface motions of gas and liquid phases under dynamic conditions, investigated the influences of engine speed and filling ratio on the interface motion, and derived the mechanism for heat transfer enhancement. Numerical simulations further explored turbulent mixing characteristics of gas-liquid mixture and reciprocating impinging effect on walls under various dynamic conditions. Coupled with a geometric reconstruction scheme, gas and liquid flow patterns were tracked by the Eulerian model, and then compared with results from VOF and CLSVOF models. A rough criterion was proposed to qualitatively estimate heat transfer enhancement of gas-liquid two-phase flow during periodic piston motion.