Influence of vibration on aerothermal characteristics of turbine blade tips under maneuvering loads

In order to investigate the influence of high-pressure turbine rotor vibration caused by dynamic load on the aerodynamic and heat transfer characteristics of the rotor blade tip with grooves, the time-averaged and transient aerodynamic and thermal performance of the non-air-cooled and air-cooled grooved blade tips under the influence of vibration were compared and analyzed by numerical simulation method. The influence of vibration on the time-averaged characteristics is limited. The average total pressure loss coefficient under the condition of no air-cooled blade tip vibration is 0.2% lower than that without vibration (from 0.094 6 to 0.094 4), and the fluctuation of the surface average heat transfer coefficient is less than 0.2%. For the air-cooled blade tip vibration condition, the average total pressure loss coefficient is 3.8% lower than that without vibration, and the surface average heat transfer coefficient is reduced by 0.8%. The transient characteristics analysis shows that the instantaneous leakage flow rate, the surface average total pressure loss coefficient and the heat transfer coefficient of the air-cooled blade tip are positively correlated with the amplitude. The heat transfer coefficient of the 10%-70% axial chord length at the bottom of the groove and the 10%-60% axial chord length at the top of the shoulder wall is sensitive to the amplitude change. Under the combined action of cooling air mixing and vibration, the strength of the vortex system increases, the fluctuation of the aerodynamic loss increases, and the non-uniformity of the heat transfer at the bottom of the groove increases. Among them, the heat transfer coefficient of the top surface of the trailing-edge shoulder wall is significantly affected by vibration and hardly covered by the coolant, to which should be paid attention in the design.