Question

A turbine blade of solution annealed INCOLOY alloy 800 is 18 in long and operates at 1400 degrees Fahrenheit. If the tip clearance is 0.2 in and centrifugal forces induce an average longitudinal stress of 10 ksi. After how many hours is expected the blade to interfere with the turbine stator due to creep?

Answer 1

solution : Griven that working temperature 14004 The Tensile Modulous of Incoloy alloy 800. at the given temporature is given in the below table. modulous = 21.06 x 103 ksi Stress Strain 21.06x103ksi loksi Longitudinal stress a 10 Given that the Strain stress 21.06*103 21.068103 = 0.00047s incher/sec diameter is 18 inches 0.2 inches. Centrifugal face acts both side we have to consider radial growth only time to fill 0.2 = 4 21.2 Seconds 0.000425 Gap the gap = 7.02 min 0.417 howy

Table 4 - Modulus of Elasticity Temperature Shear Modulus Poisson's Ratio °F -310 75 200 400 600 800 1000 1200 1400 1600 Tensile Modulus 108 ksi 30.55 28.50 27.82 26.81 25.71 24.64 23.52 22.37 21.06 19.20 109 ksi 11.45 10.64 10.37 9.91 9.47 9.04 8.60 8.12 7.58 6.82 0.334 0.339 0.341 0.353 0.357 0.363 0.367 0.377 0.389 0.408