A thermal buckling analysis method based on sub-model

During the test run of a type of turbofan engine, the lobe-shaped deformation of the inner ring of a turbine nozzle was found. This paper carried out related analysis and research work. Firstly, based on the local thermal buckling theory, a thermal buckling discrimination and optimization method based on the local structure is developed and applied to the deformation failure of the turbine nozzle. The method extracts the boundary conditions of the compressive stress concentration region, and uses the critical pressure derived from the equivalent stress calculation formula as the criterion for determining the local instability. The discriminant results demonstrate that due to the large temperature gradient between the inner and outer rings of the turbine nozzle and the sealing design to prevent airflow backflow, the thermal buckling of the seal lip is caused. Based on the theoretical solution and numerical simulation, the geometry and boundary optimization of the local structure of the turbine nozzle is carried out. After optimization, the static strength and buckling safety factor meet the design criteria. The method proposed to consider the thermal buckling of complex structures caused by thermal stress in a non-uniform temperature field can greatly simplify the calculation process and improve the design level of thermal structure.