Method for introducing a deliberate mismatch on a turbomachine bladed wheel and bladed wheel with a deliberate mismatch
원문보기
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
F01D-005/00
F01D-025/06
F01D-025/00
출원번호
US-0107877
(2005-04-18)
등록번호
US-7500299
(2009-03-10)
우선권정보
FR-04 04130(2004-04-20)
발명자
/ 주소
Dupeux,J��r��me
Dupont,Christian
Lombard,Jean Pierre
Seinturier,Eric
출원인 / 주소
SNECMA
대리인 / 주소
Oblon, Spivak, McClelland, Maier & Neustadt, P.C.
인용정보
피인용 횟수 :
15인용 특허 :
4
초록▼
A method to introduce a deliberate mismatch into a turbomachine bladed wheel so as to reduce vibration amplitudes of the wheel in forced response. The method includes a step of determining an optimum value of the standard deviation for the mismatch as a function of operating conditions of the wheel
A method to introduce a deliberate mismatch into a turbomachine bladed wheel so as to reduce vibration amplitudes of the wheel in forced response. The method includes a step 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. The method further includes a step of at least partly placing blades with different natural frequencies on the wheel such that the standard deviation of the frequency distribution of all blades is equal to at least the mismatch value, the mismatch value being determined statistically.
대표청구항▼
The invention claimed is: 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 functio
The invention claimed is: 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. 2. The method according to claim 1, wherein the number of different blade natural frequencies outside manufacturing tolerances is limited to three. 3. The method according to claim 2, comprising distributing blades according to patterns with blades with natural frequency f1 and blades with natural frequency f2, f2 being different from f1. 4. The method according to claim 3, wherein subsequent patterns are similar or vary slightly from one pattern to the next. 5. The method according to claim 4, wherein each pattern includes (s1+s2) blades, s1 blades with frequency f1 and s2 blades with frequency f2. 6. The method according to claim 5, wherein s1=s2 and s1 is not greater than the total number N of blades in the wheel divided by 4. 7. The method according to claim 4, wherein each pattern comprises (s1+s2+/-2) blades, including (s1+/-1) blades with frequency f1 and (s2+/-1) blades with frequency f2. 8. The method according to claim 2, further comprising subjecting the bladed wheel to a harmonic excitation of n disturbances per revolution, wherein n is less than the number N of blades in the bladed wheel divided by two (nN/2), and wherein a number of patterns is equal to a number of diameters in the mode concerned. 10. The method according to claim 2, further comprising modifying the resonant frequency of the blades by geometrically modifying the blades. 11. The method according to claim 2, further comprising modifying the resonant frequency of the blades by geometrically modifying blade roots, the blades not being modified, so as to modify the stiffness. 12. The method according to claim 2, further comprising modifying the resonant frequency of the blades by adding mass or varying the material from which the blades are made. 13. The method according to claim 12, wherein the blades are hollow or recessed, and said modifying is induced by filling in part of cavities with a material of an appropriate density. 14. The method according to claim 3, wherein a fillet between the blade and a hub varies from one blade to the next. 15. 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: statistically 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, calculating an average of damping coefficients corresponding to each possible phase angle between the blades, and checking that an aeroelastic damping of a mode concerned by floating is less than said average, to firstly determine if introducing a deliberate mismatch improves the aeroelastic stability.
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이 특허에 인용된 특허 (4)
Griffin,Jerry H.; Feiner,Drew M., Fundamental mistuning model for determining system properties and predicting vibratory response of bladed disks.
Kuehhorn, Arnold; Klauke, Thomas, Method of manufacturing integrally designed rotor wheels to exhibit an essentially identical natural frequency and mass using chemical etch machining.
Schlinker, Robert Hans; Napier, James C.; Polak, David R.; Lin, Ray-Sing; Liljenberg, Scott A.; Jones, Anthony C., System for reducing compressor noise.
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