Session: 27-04 Methods and Modeling in Rotordynamics

Paper Number: 128790

128790 - Accuracy Analysis of Multi-Plane Unbalance Identification Using Different Model Order Reduction Techniques 

The reliability in the estimation of multi-plane unbalance in the turbomachinery is an active area of research. Different model-based identification algorithms are being utilized to identify the magnitude and the phase of the residual unbalances from the vibration responses. However, with a limited number of measurement planes, model reduction techniques are usually employed in the identification algorithms. These techniques can reduce the degrees of freedom (Dofs) of the model, but they may also alter the dynamic behavior of the system. Therefore, it is necessary to analyze the accuracy in the prediction of the faults in scenarios where the model is reduced. In the present work, for the identification of unbalances at multiple planes, model-based approaches are compared by implementing different reduction techniques such as static Guyan reduction, dynamic Guyan reduction, dynamic Guyan reduction with gyroscopic effect, and system equivalent reduction expansion process (SEREP). Rotor bearing systems with multiple disks located in between bearings as well as in overhung condition are considered as a case example to ensure the general applicability of the algorithm in industrial applications with versatile configurations of impellers. The vibration responses at the disk locations are considered for the estimation of the unbalances. It is observed that with different reduced model, the accuracy in estimation varied significantly, especially in the vicinity of resonance and at higher speeds due to presence of gyroscopic effects in the system. The percentage error in the unbalance estimation is compared for different reduction methods at several operating speeds. These results are used to establish the suitable speed range in which each individual reduction method can be used for balancing with estimated unbalance values. 

Presenting Author: Khurram Shehzad Lappeenranta-Lahti University of Technology LUT

Presenting Author Biography: Khurram Shehzad was born in Rawalpindi, Pakistan in 1987. He received his MSc. degree in mechanical engineering from University of Engineering and Technology Taxila in 2019.He was research associate in Institute of Space Technology Islamabad, Pakistan from 2012 to 2022.Currently, he is a junior researcher pursuing his D.Sc. degree at Machine Dynamics Laboratory, LUT University. His area of interest is applied dynamics, modal analysis and unbalance identification in turbomachinery.

Authors:

Khurram Shehzad Lappeenranta-Lahti University of Technology LUT
Gyan Ranjan Lappeenranta-Lahti University of Technology LUT
Tuhin Choudhury Lappeenranta-Lahti University of Technology LUT
Charles Nutakor Lappeenranta-Lahti University of Technology LUT
Jussi Sopanen Lappeenranta-Lahti University of Technology LUT