Effects of surface roughness and nonparallelism on the measurement of the acoustic nonlinearity parameter in steam turbine blades

Na, Jeong K.; Yost, William T.; Cantrell, John H.; Kessel, Gregory L.
May 2000
AIP Conference Proceedings;2000, Vol. 509 Issue 1, p1417
Academic Journal
The effects of surface roughness and nonparallelism of steam turbine blades have been measured by constructing different specimens made of 410Cb stainless steel, a popular material used in turbine blade construction. The sample specimens contain angles typically encountered in turbine blade measurement. Surface roughness often found in turbines during service life is incorporated in the samples. At each level of surface roughness and at each angle, the nonlinearity parameter β of the specimens has been measured. The experimental results show that β decreases as the level of roughness increases, while it increases as the degree of nonparallelism increases. Calibration factors for both specimen angle and surface roughness are determined, and comparison with some model calculations is made. © 2000 American Institute of Physics.


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