Session: 23-11, Labyrinth Seals

Paper Number: 126770

126770 - Effect of Labyrinth Seal Parameters on Leakage and Rotordynamics in a Centrifugal Compressor Supported by Active Magnetic Bearings 

Centrifugal compressors will play a key role in efficiency of energy transition from fossil fuels in commercial and district heating applications. The overall efficiency of such compressors can be further improved by incorporating active magnetic bearings and high-speed direct drives, especially in high temperature, high-capacity heat pumps. However, at high speeds, the sealing of the refrigerants can present several challenges related to leakage and rotordynamic instability. Typically, hermetically sealed compressor design provides a simple, cost-effective solution with radial or axial labyrinth seals to separate compressor stages from the motor components and bearings. However, significant leakage from labyrinth seals could have adverse effect on magnetic bearings, such as cooling loss, contamination and imbalance. Moreover, asymmetric pressure distribution across impeller back plate or shaft surface can often lead to large cross coupling dynamic coefficients, thereby increasing the chances of instability during operation. To that end, this paper investigates how different seal parameters effect the leakage and rotordynamics in a single stage compressor. For both axial and radial labyrinth seals, the study presents the correlation between seal parameters and leakage. Lastly, a rotordynamic model is developed  for the rotor -magnetic bearing system, including the dynamic coefficients of the seals and the impeller, and any possible instability are investigated.

Presenting Author: Tuhin Choudhury Lappeenranta-Lahti University of Technology LUT

Presenting Author Biography: Tuhin Choudhury, as a B.Sc. in mechanical engineering ('07 - '11, SMIT, India), initially worked on the design and development of medical devices and diagnostic instruments ('11 - '16, TCS, India). Later, he specialized in mechatronic system design during his M.Sc. (tech) in mechanical engineering ('16 - '18, LUT University, Finland). During his Ph.D. ('18 - '22, LUT University, Finland) his focus was on modeling and simulation of rotating machines, fault estimation, and parameter identification.

As a post doc researcher, his research interests include design, modeling, and simulation of high speed rotating machines and their role in energy transition to carbon neutral solutions, especially focusing on design and analysis of large scale compressors for district heating applications.

Authors:

Tuhin Choudhury Lappeenranta-Lahti University of Technology LUT
Gyan Ranjan Lappeenranta-Lahti University of Technology LUT
Alexander Smirnov Spindrive Oy
Janne Heikkinen Spindrive Oy
Lauri Rauhala Mertala Innovations Oy
Jussi Sopanen Lappeenranta-Lahti University of Technology LUT