Dynamic characteristics of a dual-rotor system with parallel non-concentricity caused by inter-shaft bearing positioning deviation. (June 2023)

• Record Type: Journal Article
• Authors: Hou, Shengliang; Lin, Rongzhou; Hou, Lei; Chen, Yushu
• Is Part Of: Mechanism and machine theory. Volume 184(2023)
• Publication Date: 2023-06
• Subjects: Parallel non-concentricity -- Inter-shaft bearing -- Orbit -- Phase angle -- Frequency; Machine theory -- Periodicals; Machinery -- Periodicals; Machines -- Périodiques; Génie mécanique -- Périodiques; Machine theory; Machinery; Periodicals; 621.81
• DOI: 10.1016/j.mechmachtheory.2023.105262
• Languages: English
• ISSNs: 0094-114X

Abstract

Highlights: A type of parallel non-concentricity is defined. The dual-rotor system model with non-concentricity is established. The envelope curve of the orbit and polar angle difference are discussed. The relation between the polar angle difference and the phase angles is calculated. The effects of the non-concentricity phase angle and the offset are discussed. Abstract: The machining deviation of the positioning hole of the inter-shaft bearing can cause the fault of the non-concentricity of the dual-rotor system. Aiming at the above problem, a type of parallel non-concentricity is defined, the phase angle and the offset of which are utilized to modify the contact force model of the inter-shaft bearing. The results obtained by the Newmark-β method show that the non-concentricity phase angle and the non-concentricity offset will change the amplitude when the dual-rotor system passes the first critical speed. It is observed that there are 2X and 3X frequencies of the rotational speeds of high- and low-pressure rotors and several combination frequencies of the two rotational speeds, in which the subtraction frequency of high- and low-pressure rotors is dominant. With the non-concentricity phase angle changes, the shape of the orbit and the envelope curve of the orbit of high- and low-pressure rotors will shift. The quantitative correspondence between the polar angle difference and the non-concentricity phase angles is discovered, which can be used to diagnose the fault of the non-concentricity of the dual-rotor system.