A numerical simulation study of fluid-solid-thermal bidirectional coupling in an aviation kerosene engine piston and piston cooling gallery based on experiments

As engines progressively move toward higher reinforcement, piston reliability faces significant challenges. In this context, the piston cooling gallery (PCG) has gradually become a key technology for highly reinforced pistons. To more accurately simulate piston temperature and gain a deeper understanding of the interaction between the PCG and the piston, a fluid-solid-thermal bidirectional coupling model was established based on thermal boundary conditions derived from three-dimensional combustion (3DC). Temperature measurement experiments were conducted using a self-developed micro temperature measurement device, and the fluid-solid-thermal bidirectional coupling model was validated based on these temperature measurement experiments and oscillating flow experiments. The study investigated the effects of different oil injection parameters on the oscillating flow of oil in the PCG, the average heat transfer coefficient (AHTC) of the wall, piston temperature, and the thermal-mechanical coupling (TMC) stress and deformation of the piston. The findings indicate that when the oil injection pressure is increased from 500 to 1700 kPa, the AHTC of the top wall, bottom wall, inner wall, and outer wall increases by 21.11%, 24.02%, 38.34%, and 34.54%, respectively, while the maximum piston temperature decreases by 7.12°C. As the oil temperature decreases from 121°C to 55°C, the AHTC of the top wall, bottom wall, inner wall, and outer wall increases by 37.71%, 48.67%, 34.76%, and 49.07%, respectively, leading to a reduction in the maximum piston temperature by 12.23°C. The TMC stress and deformation of the piston vary under different oil injection schemes.