Porous medium flow simulation in a brush seal with radial clearance

Abstract

The application of sealing technologies in the field of turbo machinery brings a significant improvement at the turbo machine efficiency. The sealing technologies undergo constant development and improvement.<br />If it is thought that the first brush seal application was tried in 40s, it can be rather said that the progress and development is unstoppable.<br />One of the most important sealing technologies is brush seal technology.<br />This sealing technology has an important role to improve the internal flow system in turbo machinery. Big power requirements from the aero engine gas turbines driven to higher pressure ratios, by-pass ratios and turbine inlet temperatures. Due to these effects, the air flows in the internal air system and thermodynamically loses increase. Internal flow system is important for the engine efficiency. Therefore the aim is always reducing the internal airflows therewithal increasing thermodynamic efficiency. Brush seals give this opportunity for turbo machines. On the other hand, labyrinth seal technology is also very well developed but the leakages are still high. Brush seals fulfill such conditions. But brush seals have also different disadvantages like bristle wearing und etc. Therefore designers are always looking for new designs. And one of them is brush seal with radial clearance. With these designs, it is tried to reach optimum clearance between rotor and bristle tips. It is tried to avoid from the leakage like labyrinth seals, at the same time avoid from the wearing problem like in brush seals.<br />This work's intention is to develop and to simulate a model which has optimum clearance with brush sealing and comparing with existing investigations.