A New Method for Field-Balancing of High-Speed Flexible Rotors without Trial Weights

Abstract

Flexible rotor balancing, in general, relies to a great extent on physical insight into the modal nature of the unbalance response. The objective of this investigation is to develop a hybrid experimental/analytical technique for balancing high-speed flexible rotors. The developed technique adopts an approach that combines the finite element modeling, experimental modal analysis, vibration measurements, and mathematical identification. The modal imbalances are identified and then transformed to the nodal space, in order to determine a set of physical balancing masses at some selected correction planes. The developed method does not rely on trial runs. In addition, the method does not require operating the supercritical rotor in a high-speed balancing facility, while accounting for the contribution of higher significant modes. The developed scheme is applied to a multidisk, multibearing, high-speed flexible rotor, where the interaction between the rotor-bending operating deflections and the forces resulting from the residual unbalance are appreciable. Some new benchmark solutions and observations are reported. The applicability, reliability, and challenges that may be encountered in field applications are addressed.

Investigation on a No Trial Weight Spray Online Dynamic Balancer

“…In 2009, Niebsch and Ramlau [17,18] used wind turbines as the research object to study illconditioned phenomena in the inverse problem of the no trial weight balance method. Khulief et al [19] and Li et al [20] simulated the functional expressions of the principal modes of the various stages of the rotor based on the finite element theory, and a good balancing effect is achieved. Research on spindle online vibration suppression technology began in the middle of the last century.…”

Methodology to improve mode identification and modal parameter extraction for rotor dynamic analysis

“…Recently, a general procedure using modal analysis for the balancing of a flexible rotor, which can be applied to a single mode, was described in [10]. According to [10], using the proposed method generates an unbalanced residue due to the modal coupling effects.…”

“…Recently, a general procedure using modal analysis for the balancing of a flexible rotor, which can be applied to a single mode, was described in [10]. According to [10], using the proposed method generates an unbalanced residue due to the modal coupling effects. In addition, an angular error in the localization of the shaft mass, caused mainly by a deviation between the angular position of the transducer and the Principal Axes of Stiffness (PAS), is reported in [11].…”

Rotor Unbalance Estimation with Reduced Number of Sensors

“…Several vibration-based rotor fault identification methods have been proposed in the literature [1][2][3][4][5][6][7][8][9][10]. The influence coefficient (IC) balancing method [11][12][13][14][15], the modal balancing [7] and other balancing methods [16][17][18][19][20][21][22][23][24][25][26][27][28][29] are the most utilized vibration-based unbalance identification methods.…”

“…The influence coefficient (IC) balancing method [11][12][13][14][15], the modal balancing [7] and other balancing methods [16][17][18][19][20][21][22][23][24][25][26][27][28][29] are the most utilized vibration-based unbalance identification methods. In order to apply the modal balancing method effectively, an accurate numerical model of the rotor and a highly skilled engineer with thorough knowledge of rotor dynamics are required [8].…”