Heat Transfering Design For Air-Cooled Turbine Blades

Gas turbine has significant importance for energy, aerospace, and military industries. Higher turbine inlet temperature results in better gas turbine performance, so the inlet temperature of a modern gas turbine always far exceeds that the blade material could bear. It is a critical issue to install blades with proper air-cooling structure through turbine blade heat transferring design and calculation. Technology for turbine blade heat transferring design, which permanently hinders the development of Chinese gas turbine industry, is essential for gas turbine engineering design. However, progresses in computer technology and numerical simulation technology are providing a new platform for gas turbine engineering design. In this situation, the main task of this thesis is to study and composed a new air-cooled blade multi-level heat transferring design method.The procedure of this air-cooled blade heat transferring design method consists of three levels, which are preliminary design, schematic design, and detailed design. Blade cooling structure design uses parameterized design method. Schematic design level uses 1-D pipe-net calculation method, and detailed design level uses 3-D conjugate heat transfer simulation method for preformence prediction. The program & software platform for this air-cooled blade heat transferring design method was built, which reduced the difficulty of designing and enabled automatic design & calculation to some extent.Parameterized air-cooled blade design method includes different methods for blade profile, coolant tunnel, and various cooling structures which were separately built and put together into an integral program platform for parameterized design. The key parameterizing algorithm named"Element Design Method"is invented and introduced, which brings about parameteried design for complex coolant tunnel and accelerates the generation of calculation model for schematic design and detailed design.For schematic design, the automatic pipe-net model generation program was developed based on parameterized method. The pipe-net solver composed consists of pressure solving program, temperature solving program, and film cooling solving program. Pressure solving program uses linearized method to solve the momentum equation, and high stability of the pipe-net solver is achieved subsequently. In detailed design, simulation methodology studied and introduced in this thesis can guarantee higher feasibility, effecincy, and accuracy in conjugate heat transfer simulation using ANSYS CFX. Rational choosing and dividing the conjudate simulation domains could not only reduce the difficulty of pre-treatment, but also increace accuracy for more multi-block structured mesh could be introduced. Data exportation program from parameterized design program to UG NX could cut down time taken by modeling. To reduce the difficulty of grid generation and assure the precision of simulation, certain principles must be adopted when using ANSYS ICEM.Automatic grid generation programs were composed to get general 2-D multi-block structured grid and flow & conjugate heat transfer multi-block structured grid of certain parts of air-cooled blade domains. And unstructured mesh generation program developing is attempted. Automatic grid generation programs, combined with parameterized method, can creat mesh for blade cascade and some cooling structures with considerable speed and quality, so the difficulty of grid generation is reduced and the automatic degree of designing is heighten.