A unique device for dynamically balancing of rotor structures has been developed by researchers of South Ural State University. The invention will help compensate for the deviations in rotor operation without interrupting the production process.
The development by the SUSU researchers is a bright example of technology transfer from the aerospace industry to general mechanical engineering. Their new device is applicable to rotating structures such as large turbines, machine tool rotors, shafts, and propellers.
The process of rotor balancing is particularly important. When a rotating structure is unbalanced, additional runout loads are appear, and the support assembly may fail, which can impair the operation of the entire shaft or turbine.
“A car wheel would be a perfect example: ideally, it should be symmetrical and with its centre of mass aligned with the axis of rotation, which minimizes wobble,” says junior research fellow of the SUSU Laboratory for Research of the Physical and Chemical Properties and Gas Dynamics of Propulsion Systems for Reusable Launch Vehicles Evgeniy Mikhailov. “Our device allows for automatic rotor balancing, eliminating the need to shut down, say, a turbine or a production machine to disassemble and manually balance the rotor.”
When asymmetry occurs, the centre of mass shifts off the axis of rotation, and together with the deviation of the axis of inertia this leads to additional loads that can lead to failure of, for example, a hydroelectric power plant turbine.
Rotor balancing methods on balancing machines currently exist, but the drawback of this method is that it requires shutting down the entire device, which takes up production time.
A unique device in the form of a fixed platform, developed by the Chelyabinsk scientists, allows for the mass redistribution of the entire rotor system by containing an integrated load. During operation, the device automatically shifts the load to the required distance and tilts it at the required angles, bringing the system into balance.
“The existing automatic balancing systems only shift the rotor’s centre of mass, but they do not eliminate the deviation of the axis of inertia, meaning they do not perform dynamic balancing,” explains Evgeniy Mikhailov. “Thus, the imbalance is reduced, but not by 100%. If dynamic balancing of a rotor is required, either two such systems can be installed, provided the rotor design allows for this, or our more multi-purpose device can be installed, which allows for effective correction of the centre of mass and axis of inertia in a single step.”
Today, the device for dynamically balancing rotor structures exists as a mathematical model, and the development is ready for implementation by the university's industrial partners.