Analysis Of Flow Performance And Strength Of Blades With Tip Slots

Secondary flow loss holds a sizable part in total turbomachinery loss. In modern turbomachine design, it is important to improve the efficiency through controlling the secondary flow loss in cascade. The distortion of blade shape appears due to the measures adopted to improve the turbomachinery efficiency, which makes the problem of turbomachinery strength much more crucial.First, numerical simulation of the first stage in one LP turbine is carried out. Slots with different types and locations across from pressure surface to suction surface at rotor tip are machined so as to allow the transfixion of pressure surface and suction surface at end wall and air flowing in along suction surface to influence secondary flow at end wall. Contrasts and analyses of flow fields in turbine stage with different slotting types are made to investigate the impact of slot at rotor tip on the turbine efficiency and secondary flow loss. Second, two types of slotting at stator tip across from suction to suction surface and from pressure to suction surface are created and the contrast of flow field fore and aft slotting is made to study the influence of stator tip slotting on turbine stage efficiency and secondary flow loss.Third, Finite Element Method and Fluid-Structure Interaction Method are applied combined with thermodynamic results to the strength analysis of rotor blade at the common action of thermodynamic force and centrifugal force. Contrast of blade strengths fore and aft slotting is made to investigate the impact of slotting on blade strength.Finally, prestressed modal analysis of rotor fore and aft slotting is made to investigate the impact of slotting on the natural mode shape and frequency which could provide reference for blade vibration analysis.