Numerical simulation of leading-edge film cooling on the rotating twisted turbine blade

Under actual high-speed rotation conditions of aero-engine and gas turbine, the fluid experienced enhanced effects from rotational forces including Coriolis force, centrifugal force, and buoyancy force. This resulted in differences in how parameters such as rotation (angle of attack) and blowing ratio (M) influenced the film cooling effectiveness (η) on turbine blade leading edges, compared with low-speed experimental conditions. A numerical simulation was performed under real aero-engine high-speed rotation conditions to investigate the effects of rotational angular velocity and M on the film cooling characteristics of an actual twisted turbine blade leading edge. The rotational angular velocities were set to 1350 rad/s (positive angle of attack), 1400 rad/s (zero angle of attack), and 1450 rad/s (negative angle of attack), with a M ranging from 0.5 to 1.25 and a jet-to-mainstream density ratio of 1.04. The mechanism by which rotation (angle of attack) and M affected the of the actual twisted turbine blade leading edge in a high-speed rotating state was revealed. Results indicated that the rotation (angle of attack) is a key factor determining the distribution on the leading edge. The stagnation line position shifted from the region between the pressure-side row and the stagnation row holes, first to near the stagnation row holes centerline, and then to the region between the stagnation row and the suction-side row holes. The spanwise-averaged film cooling effectiveness （$ \overline{\eta } $） on the leading edge region exhibited a nonlinear variation with the increasing M, and differences were observed in specific areas. When no take-off phenomenon occurred on the leading edge (M=0.5), the Coriolis force component acting on the coolant in the leading edge cavity was directly oriented toward the stagnation row of holes. This not only facilitated the outflow of coolant from the stagnation row holes but also promoted a greater flow rate of coolant discharging from lower-radius locations. Another component of the Coriolis force drove the coolant toward the pressure-side, making it beneficial for the coolant outflow from the pressure-side row holes.