| US 7,500,299 B2 | ||
| Method for introducing a deliberate mismatch on a turbomachine bladed wheel and bladed wheel with a deliberate mismatch | ||
| Jérôme Dupeux, Vaux le Penil (France); Christian Dupont, Dammarie les Lys (France); Jean-Pierre Lombard, Pamfou (France); and Eric Seinturier, Bruges (France) | ||
| Assigned to SNECMA, Paris (France) | ||
| Filed on Apr. 18, 2005, as Appl. No. 11/107,877. | ||
| Claims priority of application No. 04 04130 (FR), filed on Apr. 20, 2004. | ||
| Prior Publication US 2005/0249586 A1, Nov. 10, 2005 | ||
| Int. Cl. F01D 5/00 (2006.01); F01D 25/06 (2006.01) | ||
| U.S. Cl. 29—407.07 [29/889; 29/889.1; 29/889.21; 416/61; 416/144; 416/175; 416/203; 416/500; 415/118; 415/119; 73/455; 73/660; 700/98; 700/118; 702/56] | 15 Claims |
| 1. A method for introducing a deliberate mismatch into a turbomachine bladed wheel so as to reduce vibration amplitudes of
the wheel in forced response, the method comprising the steps of:
determining an optimum value of the standard deviation for the mismatch as a function of operating conditions of the wheel
inside the turbomachine, with respect to the maximum vibration amplitude response required on the wheel, and
at least partly placing blades with different natural frequencies on said wheel such that the standard deviation of the frequency
distribution of all blades is equal to at least said mismatch value,
wherein said mismatch value is determined statistically including the following steps:
defining a first value of the mismatch standard deviation σj,
generating a statistically significant number R of random mismatch distributions within said standard deviation σj,
for each of the R random distributions, calculating the forced mismatched response as a function of the operating conditions
of the wheel inside the turbomachine,
extracting from the forced mismatched response a maximum value,
choosing another value of σj, and
repeating said calculating and extracting steps a sufficient number of iterations to obtain response values as a function
of the values σj.
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