Fluid-structure interaction heat transfer of piston with consideration of oil oscillating cooling and in-cylinder local heat transfer

Abstract

Taking the piston of heavy commercial vehicle as an example, in-cylinder local heat transfer boundary condition is obtained through the calculation of intake, spray, combustion and exhaust process; the heat transfer boundaries of the inner oil gallery and the bottom of the piston are obtained by the transient piston injection cooling calculation; the numerical simulation of temperature field of piston is realized by the coupling of gas side, lubrication oil side and structure with consideration of the temperature’s influence on the thermal conductivity of the piston. Furthermore, the thermal deformation of the piston is analysed. Results show that the calculated values are in agreement with the experimental temperature values of the piston measuring points; The highest temperature appears at the junction of the bowl and the top surface of the piston at the exhaust valve side; The heat transfer coefficient and gas temperature at the junction of the bowl and the top surface of the piston are in high value, the in-cylinder local heat transfer is significant ; In the straight inlet pipe of the inner oil gallery, the temperature of the lube oil is the lowest while heat transfer coefficient is the highest, so the cooling effect is the most obvious; The radial expansion deformation is large at the top and bottom of the piston skirt while small at the middle.