Blade tip rubs have been explored at the GTL in a vacuum at room temperature in both the Compressor Spin Pit Facility (CSPF) and the Large Spin Pit Facility (LSPF). The previous work in this area has been published in a variety of journals and conferences.
Among the many phenomena that can be investigated in the CSPF and LSPF are asymmetric and full rotor clearance closure for actual engine stages. In single blade asymmetric clearance closure investigations, a rapid contact of the bladed rotor with its housing is simulated as would occur in an abrupt flight maneuver. In full rotor clearance closure, an extended contact of the bladed rotor with its housing is simulated as could be experienced in some flight phases due to temporary thermal imbalances in different parts of the engine.