초록 ▼

The invention relates to a control system which controls the diameter of a turbine shroud which surrounds a turbine in a gas turbine aircraft engine. The invention seeks to minimize the clearance between the turbine rotor and the shroud. Air is bled from the compressor in the engine and ducted to th

The invention relates to a control system which controls the diameter of a turbine shroud which surrounds a turbine in a gas turbine aircraft engine. The invention seeks to minimize the clearance between the turbine rotor and the shroud. Air is bled from the compressor in the engine and ducted to the shroud in order to heat or cool the shroud in order to, respectively, either expand or shrink the shroud to a proper diameter. The air temperature which is required is computed based on compressor speed and other engine parameters, but not upon directly measured rotor temperature, despite the fact that rotor temperature has a significant influence upon rotor diameter, and thus upon shroud diameter needed. Air at two different temperatures is bled from two different compressor stages in the engine and mixed together in a ratio which is determined according to flight conditions, in order to provide air of the required temperature for the shroud, and then ducted to the shroud in order to modify shroud size. Further, during accelerations and decelerations of the engine, a different air temperature is provided, as compared with that provided during steady state operation. In the event that the system just described should fail, back-up systems control shroud diameter. There exist two back-up systems, one for use during steady state, and the other for use during accelerations and decelerations.

대표청구항 ▼

A method of controlling tip clearance in a turbine in a gas turbine engine, comprising the following steps: (a) ascertaining turbine rotor temperature; (b) computing a demanded shroud temperature in response to the rotor temperature; and (c) adjusting actual shroud temperature in response to the dem

A method of controlling tip clearance in a turbine in a gas turbine engine, comprising the following steps: (a) ascertaining turbine rotor temperature; (b) computing a demanded shroud temperature in response to the rotor temperature; and (c) adjusting actual shroud temperature in response to the demanded shroud temperature.