Introduction To Brush Seals

A brush seal consists of a densely arranged array of bristles-fixed at one end and free at the other-positioned adjacent to or in contact with the surface to be sealed, serving to separate two regions of gas or liquid at different pressures. It is a flexible sealing component designed to seal dynamically varying clearance regions. A typical brush seal features cylindrical bristles whose axes are angled relative to the sealing surface; this bristle angle, denoted as θ, typically falls within the range of 35° to 60°. When oriented in this manner, the bristles function as cantilever beams.

Brush seals represent one of the key technologies driving the development of modern, advanced turbomachinery, having originally found their application in aero-engines.

The primary advantages of brush seals are most evident under dynamic sealing conditions. Because the contact interface between the brush seal and the rotating component consists of a densely packed array of metal wires-which are, moreover, angled relative to the rotating part-this specific design configuration enables the bristles to act as cantilever beams.

Brush sealing is a highly efficient damping seal technology. Brush seals have been successfully implemented in various types of turbomachinery, including aero-engines, industrial gas turbines, and steam turbines. Within the aerospace sector, the application of brush seals constitutes a critical strategy for enhancing the performance of aero-engines.