Simulation of two-phase flow boiling heat transfer in cylinder head cooling water jacket

The computational fluid dynamics software CFX was applied and the thermodynamic phase change characteristics of the cylinder head cooling water were considered. The calculation model of sub-cooled boiling heat transfer for gas-liquid two-phase flow was used for the fluid-solid coupling heat transfer system which is composed by the diesel engine cylinder head and the cooling water jacket with the method of discretizing and solving for the entire domain. The cylinder head temperature field distribution was obtained under the different influence factor conditions and validated by the experimental data. The results show that, compared with the single-phase flow without considering the boiling heat transfer, the sub-cooled boiling heat transfer of gas-liquid two-phase flow can effectively reduce the highest temperature of the cylinder head flame-face, and increase the inlet speed of cooling water and lower the inlet temperature. In addition, the cooling system pressure drops appropriately which further reduces the cylinder head flame-face temperature, thus lowering the heat load of the cylinder head flame-face.