ACOUSTICALLY-INDUCED STRUCTURAL FATIGUE OF IMPELLER DISCS ― A BRIEF NOTE

摘要

Coincidence of both the out-of-plane structural wave numbers and frequencies of the impeller disc with the corresponding wave numbers and frequencies of the acoustic waves inside the machine casing may lead to structural-acoustic coupling, to extreme dynamic loading of the impeller disc and consequently to fatigue failures. Of primary concern is the interaction between the diametral structural modes and the higher order diametral acoustic modes. Avoiding the match between the wave numbers and assuring sufficient separation between structural and acoustic frequencies will prevent structural-acoustic coupling and eliminate the dangers of impeller disc failures from acoustic loadings. In this paper, the coupling phenomena and the relationship between the structural and acoustic fields will be discussed more broadly. A numerical example will also be included for illustration.