缸盖热疲劳裂纹扩展特点的模拟试验分析

用试验的方法研究了热疲劳裂纹的扩展过程。利用S1100柴油机模拟火力板试件，在高频感应加热器的循环加热下产生热疲劳裂纹，用光学显微镜观察其热疲劳裂纹，通过摄像机全程跟踪整个过程，并将其记录在计算机里；最后处理、分析计算机里的信息，得出了一些热疲劳裂纹长度与循环数的关系式等，并就热疲劳裂纹扩展的特点等有关问题进行了讨论。     

A New Method for Computing Radiation Heat Flow of In-Cylinder Soot of Diesel Engines

A concise formula for computing radiation heat flow of in-cylinder soot is presented,based on the assumptions that in-cylinder heat transfer of diesel engines is a quasi-equilibrium process and in-cylinder soot particles are spherical. That in this formula there consist neither constants needing adjustments nor variables related to engine types or operating conditions makes it universal and easy to use. Also it can be seen from the formula that radiation heat transfer is proportional to the quotient of in-cylinder soot mass over the average radius of primary particles. Besides, with the help of different algorithms it can be used for predicting cylinders' global as well as local radiation heat flows. As a demonstrative application on its global facet, a three-dimension simulation study about the soot-radiation-related heat flow in the combustion chamber of a diesel engine is carried out. Results show that the range of the soot-radiation-related heat flow computed by this formula agrees well with other researcher's earlier theoretic reasoning and experimental measurements.