Variable vane non-linear schedule for a gas turbine engine
First Claim
1. In a method for operating a gas turbine engine having a compressor section with a plurality of rows of variable angle stator vanes, including a variable angle IGV vane row, wherein the angle of said IGV vane row is changed as a function of engine speed, and the angle of at least one other vane row is changed as a linear function of the angle of said IGV vane row, the improvement wherein the angle of a third vance row is varied as a non-linear function of the angle of said IGV vane row, said non-linear function being approximately linear at higher engine speeds and having greater than said linear variation at engine start and idle speeds and wherein said engine has a fourth row of stator vanes following said third vane row, and wherein the angle of said forth row is maintained constant for all engine speeds.
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Accused Products
Abstract
A method and apparatus for adjusting the angle of variable angle inlet guide vanes provides a non-linear adjustment schedule for a selected vane row as compared to the adjustment schedule for the IGV vane row. The non-linear schedule is conveniently achieved by providing a modified adjustment linkage utilizing a bell crank. The non-linear schedule provides improved engine stall margin at low engine speeds.
53 Citations
3 Claims
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1. In a method for operating a gas turbine engine having a compressor section with a plurality of rows of variable angle stator vanes, including a variable angle IGV vane row, wherein the angle of said IGV vane row is changed as a function of engine speed, and the angle of at least one other vane row is changed as a linear function of the angle of said IGV vane row, the improvement wherein the angle of a third vance row is varied as a non-linear function of the angle of said IGV vane row, said non-linear function being approximately linear at higher engine speeds and having greater than said linear variation at engine start and idle speeds and wherein said engine has a fourth row of stator vanes following said third vane row, and wherein the angle of said forth row is maintained constant for all engine speeds.
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2. Apparatus for adjusting the compressor stator vane angles in a gas turbine engine having a plurality of compressor stator vane rows, comprising:
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a pump handle , having one end pivotably mounted to a stationary part of said engine, and having at least one link member connected directly thereto for adjusting the vane angle of a first of said inlet vane rows; means for selectively pivoting said pump handle about said pivotable mount in response to an engine operating condition; and a bell crank having a first pivot point mounted to a stationary part of said engine, a second pivot point mounted by a bell crank pivot link to said pump handle and a third pivot point connected to another link member for adjusting the vane angle of another of said inlet vane rows; and whereby said pivoting of said pump handle causes adjustment of the angle of said other of said vane rows in a manner that is non-linearly related to the adjustment of said angle of said first inlet vane row. - View Dependent Claims (3)
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Specification