Thermal-Flow Coupling Simulation Analysis of Small and Special Underwater Gas Turbine Disk

For the high temperature and high-speed incoming flow of small and special underwater gas turbines and the high rotary speed of the turbine disk, the temperature field of the disk and its channel are simulated by using the shear stress transport(SST) turbulence model for the fluid domain and the conjugate heat transfer method for the solid domain. Then, the temperature field is loaded into the strength analysis to simulate the thermal stress and deformation of the disk under the worst conditions. Calculation results show that the turbine disk temperature reaches the extreme value when the number of nozzles is 3; and the reverse exhaust can effectively reduce the surface temperature of the turbine disk, but its function will be limited. Without any cooling measures, the maximum temperature of the disk exceeds the maximum temperature tolerance of the material, and there is a large disk elongation in its extreme temperature range, moreover, the maximum stress value of the disk at high temperature and high rotary speed exceeds the allowable stress of the material. Therefore, certain cooling measures should be taken for the disk areas where the temperature is higher. This research may provide a reference for safety design of gas turbines.