A new research project from the Department of Energy Technology at Aalborg University, with Associate Professor Per Johansen at the forefront, will develop a new method for investigating the thickness of machines' lubrication films using ultrasound.
Friction and wear are of great importance for the life and efficiency of production machines in main energy consuming industries. In fact, over 20 percent of the world's energy consumption goes to overcome friction. Therefore, it is interesting to investigate lubrication films and lubrication technologies that may affect the friction in the machines, which affect energy consumption and wear degree.
- In the project I try to make it possible to use a new technique for measuring lubrication film thicknesses, which is relevant for energy loss and mechanical wear in industrial machines. The interesting thing about this technique is that it is based on ultrasound and does not require calibration. In the long term, this should enable a more practical measurement of machines without necessarily taking them apart, says Per Johansen.
The project is supported by the Independent Research Fund Denmark with DKK 2.8 million. The basic idea is to achieve a longer service life and higher efficiency of systems in energy consuming industries by advanced analysis and control of energy loss and wear.
New method facilitates measurement work
A significant challenge to the existing experimental techniques, which are usually used to investigate lubrication films, is that measuring lubrication film thickness on machines is problematic without making any structural changes.
- The problem arises because sensors need to be calibrated and connected. Therefore, friction and wear have traditionally been analysed in idealized laboratory test systems. Since friction is not a material property but a property of the system in which the materials work, it creates a gap between real systems and idealized test systems in laboratories. The problems can be overcome with autonomous sensor technology, where sensors transmit data wirelessly, harvest energy locally for supply and auto-calibrate, explains Per Johansen.
The Independent Research Fund Denmark project seeks to establish the auto-calibration portion of a future autonomous sensor technology. Current adaptive solutions are based on methods that do not take into account the relationships between the energy levels of different frequencies in the transmitted and reflected ultrasonic waves. The methods are therefore sensitive to external influences from eg temperature and pressure variations. The purpose of the project is to investigate a newly discovered mathematical relation between the frequency content of the transmitted and reflected waves, and the application of this relation in multi-frequency calibration algorithms.
Measurements of lubrication film thicknesses have great potential in the vision of the Industrial Internet-of-Things, where data is essential. The results of the project will provide new insights into auto-calibrating non-invasive measurement of lubrication film thicknesses. This is an important step towards an autonomous sensor technology in tribology, which can provide access to data that enables intelligent tribology systems. As a result, systems can be designed and controlled to have increased service life and efficiency.
Associate Professor Per Johansen
Direct phone: +45 9940 9737
Mobile phone: +45 3123 4812