Experimental characterization of friction and heat generation of carbon fibre brush seals for aero-engines. (November 2020)

• Record Type: Journal Article
• Authors: Outirba, Bilal; Hendrick, Patrick
• Is Part Of: Tribology international. Volume 151(2020)
• Publication Date: 2020-11
• Subjects: Brush seal -- Carbon fibre -- Friction -- Heat generation; Tribology -- Periodicals; 621.89
• DOI: 10.1016/j.triboint.2020.106448
• Languages: English
• ISSNs: 0301-679X

Abstract

Abstract: Brush seals have been extensively studied for the last thirty years as an advanced sealing solution for gas turbine engines. The research is always aimed towards the reduction of the leakage flow, that has direct repercussions on the specific fuel consumption, the thrust-to-weight ratio, and the emission of pollutants. In addition, the sealing device must cope with side effects related to higher interface speeds, rotordynamics issues, or durability. Brush seals main assets are their excellent leakage performance with low friction properties compared to other contact seals like lip seals, and their ability to withstand rotor radial excursion without permanent damage. However, proper design optimization cannot be performed without the inclusion of the tribological performance. This paper presents a parametric investigation of the friction properties of carbon fibre brush seals as a function of the fibre pack geometry and the rotational speed. Carbon fibre and commonly used metallic brush seals present fundamentally different behaviour in presence of differential pressure or rotational speed. This paper also proposes an alternative method to predict the brush seal torque, based on measurements with a torque sensor. Heat generation was also evaluated with a thermographic camera. Both methods ensured consistency between results. Highlights: Identification of the most influential phenomena and mechanisms influencing seal torque. Analysis in dry conditions as a function of the operating conditions Development of dimensionless empirical laws for brush seal torque estimation Investigation of heat generation properties using an IR camera Illustration of remarkably low friction and temperature levels