Stress analysis of twin web disk in cooled turbine rotor with cooling air

Using twin web disks instead of single disks in turbine rotor is the new idea, which provides the necessary space for cooling and thus reducing the temperature level and the resulting stresses. The disk is subject to mechanical and thermal loading. Mechanical loading involves the effect of the disk rotation and the centrifugal load caused by the blade rotation at the external surface. Thermal loading is applied due to thermal changes between the internal and external surfaces on the disk. Disk boundary conditions are considered as dual-cantilever. Using the analytical solution method, the theory of elasticity of the plate is derived from the relations that govern the thickness of a rotating disk in a plane stress state. In the following, the disk was analysed under consideration the actual thickness profile using the TimoshenkoGrameel’s numerical method. In order to reach a twin web disk with a proper profile, this disk is studied with stepped holes in 400 different geometrical modes, and the state with the lowest possible mass and acceptable reliability coefficient is obtained. The results of the analysis show the reduction of mass, reduction of stress levels and improvement of the coefficient of confidence through the use of an optimal twin web disk.