| 摘要 |
An apparatus 60 for determining a clearance between relatively movable components 30,46, such as a stator and the rotor blades of a gas turbine engine, in which an abradable material 48 is arranged on a first one 46 of the components 30,46. A first probe 51 measures a first distance D1 from a datum position 49 to a second one 30 of the components 30,46. A second probe 52 measures a second distance D2 from the datum position 49 to the surface 47 of the abradable material 48 on the first one 46 of the components 30,46. An analyser 56 subtracts the second distance D2 from the first distance D1 to determine the clearance 50 between the components 30,46. The second probe 52 may comprise at least one optical member 55 arranged to extend to different depths within the abradable material 48. At least one radiation detector 54 is arranged to detect radiation in the at least one optical member 55 and the analyser 56 is arranged to detect a difference in the radiation collected in the optical member 55 at different depths in the abradable material 48 and hence the amount of wear of the abradable material 48 produced by the components 30,46. |
