The piston Thermal Analysis
Create a Thermal Load. When Pistons are operating, they directly touch the high temperature gas and their transient temperature can reach more than 2500K and generates the 18KW power. Piston is heated seriously and its heat transfer coefficient is 167 w/m ° C and its heat dissipation condition is poor, so the piston temperature can reach 600 ~ 700 K approximately and the temperature distributes unevenly. On the basis of these conditions, we will make thermal analysis for the piston.
Results and Analysis. Through the analysis of the operation, we can get the pistons temperature field distribution, as shown in figure4. The piston temperature distributes unevenly. The maximum steady state temperature of the piston is 2500K under the temperature effect of the repeated changes in the high temperature gas. The highest temperature appears the top surface of the piston. The temperature of piston pin changes between 700K and 800K. The temperature of the first ring groove is the important evaluation index of thermal load of piston and its temperature is between 1300 K and 1500K. The highest temperature differs by 1800 K from the minimum temperature, which will
make piston cause larger thermal stress and thermal damage.
From the diagram, we can find the piston temperature is gradient descent along the piston axis direction from up to down, but the temperature change of piston skirt is lesser. The diagram indicates that thermal deformation of the piston is bigger from bottom to top and heat distortion of the bottom is minimum. These findings are consistent with domestic researchers results.