| Popis: |
Aspirating face seals are being studied as a possible replacement for labyrinth seals in aircraft engines for reduced leakage and improved engine efficiency. A 36" diameter aspirating seal, designed to fit in the GE90 engine, has undergone testing in a rig designed to mimic the pressure, rotor speed, rotor runout, and seal tilt conditions expected in actual service. Seal/rotor axial clearances are monitored during testing. Results to date indicate a strong interaction between seal air dam flow and hydrostatic bearing flow, and the resultant loads imposed on the seal appear to be greater than those expected by hydrostatic bearing theory. As a result, the seal seeks an equilibrium position at an axial rotor clearance of 0.016", rather than the expected 0.0015"-0.003". The results of 3D Computational Fluid Dynamics (CFD) analyses support the test results, and studies are underway to identify seal and/or rotor modifications that will allow the seal to close to its intended clearance. These include modifications to isolate flows from the dam and air bearing regions of the seal. This paper covers the following: the full scale test facility, the test sequence and results, the analytical results, and future plans. |
