| Abstract:To accurately control turbine blade throat area, mitigate the negative effect of turbine blade throat area deviation on turbine
performance, taking the 1st stage blade of a GE high pressure turbine as the research object, a turbine blade throat area calculating method
based on airfoil position tolerance, airfoil twist angle tolerance, airfoil profile tolerance, and endwall profile tolerance was proposed. Initial
tolerances for the above-mentioned parameters were set according to the aviation industry standard (HB 5647-98), and detailed analyses
were conducted to reveal their effects on the throat area. A stochastic analysis method was applied to study the deviation distribution of
throat areas. The results show that the airfoil positions have little effect on the throat area due to their opposite effects on throat widths of
left and right passages, the variations of throat areas are no more than ±0.005% when airfoils deviate in axial or circumferential direction.
In contrast, airfoil twist angle and airfoil profile deviation significantly affect the throat area. When the airfoils of the hub, mid and tip sec?
tions are rotated 0.1 degrees, the throat areas vary by 0.13%, 0.14%, and 0.15%, respectively. When the profile of the suction side and trail?
ing edge vary by 0.1mm, the throat area varies by 0.08%. When the endwall profile varies by 0.1mm, the throat area varies by 0.06%. When
the airfoil size parameters all conform to normal distributions within their tolerance range, the deviations of throat areas also conform to
normal distribution, with its ±3 standard deviations equal to ±0.91% of the nominal throat area. |
