Film Cooling Design And Multi-field Coupling Analysis Of Turbine Vanes

With the increase of the inlet temperature of gas turbines, cooling should be used for the hot-sections. Film cooling is one of the most effective cooling techniques. Film cooling properties and mechanism for the flat-plate and turbine guide vane are studied in the present work. And a new assessment method for the cooling structure is put forward as the reference of cooling design of guide vanes.In the study of flat-plate film cooling, the combination of numerical method and experiment is applied to the investigation of properties and mechanism of cylindrical, fan-shaped and double jet film cooling (DJFC) holes. The technology of pressure sensitive paint (PSP) is utilized for measurement of cooling effectiveness. Before the measurements, a calibration device is established and the PSP is calibrated. The effects of streamwise distance, spanwise distance, compound angle and blowing ratios on the cooling performance are comprehensively studied. The results showed that the vortex structures mainly affect the cooling effectiveness of DJFC holes. Choosing suitable geometrical parameters to form the effective anti-kidney vortices is the key of improving the cooling effectiveness. For the film cooling of the guide vane, numerical method is used to study the cooling effectiveness of double jet holes on the pressure surface and suction surface, and improvement is achieved by arranging the DJFC holes according to the cooling mechanism studied on flat-plate. The results showed that DJFC holes perform very well on the suction surface, but on the pressure surface the cooling effectiveness of DJFC holes is easily affected by the local secondary flow.Multi-field coupling method is used to assess the film cooling properties of the flat-plate and the guide vane. The effects of blowing ratios and hole types on the stress around the film cooling holes on a flat plate are studied and compared. In the analysis of the cooling effectiveness of the guide vane, creep strain is used to evaluate the cooling structure, in order to take into account the effects of both temperature and thermal stress. Corresponding studies e and improvement on the guide van are made in order to prolong the life of usage.