Patent ID: 8550768
Filing Date: 2013-10-08
Classification: F01D,F04D,F05D

Abstract:
1. A method of improving a stall margin of an axial flow compressor in a gas turbine engine, comprising the steps of: (a) analytically calculating a baseline performance from a baseline performance analysis for at least one row of rotating compressor blades; (b) analytically determining a flow field from the baseline performance analysis for the at least one row of rotating compressor blades at a blade tip region and at an off-design point; (c) analytically modeling at least one circumferential groove in a smooth wall of a compressor casing with a groove placement and a groove geometry determined using a set of results obtained in step (b), wherein operating the compressor with the circumferential groove in a casing wall increases a stall margin of the at least one row of rotating compressor blades; (d) performing a subsequent analytical performance calculation of the at least one row of rotating compressor blades with the at least one groove analytically modeled in a smooth wall of the compressor casing; (e) comparing a subsequent performance determined from the subsequent analytical performance calculation to the baseline performance, and a subsequent stall margin determined from the subsequent analytical performance calculation to a baseline stall margin determined from the baseline performance analysis; (f) determining if a change in the subsequent performance when compared to the baseline performance and a change in the subsequent stall margin when compared to the baseline stall margin satisfies an acceptance criteria; (g) adjusting at least one of a plurality of groove parameters of the at least one groove and repeating steps (c) through (f) until the change in the subsequent performance to the baseline performance and the change in the subsequent stall margin to the baseline stall margin satisfies the acceptance criteria; and (h) machining a groove profile defined by the plurality of groove parameters in the smooth wall of the compressor casing.