Gas Turbine Fan Casing Flange Setback for Equipment Fastening
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Solution Overview
Problem
The existing composite material fan casings in gas turbine engines are weakened by the need for festoons in the flange to accommodate equipment fastening, which compromises the circumferential mechanical strength when trying to remove equipment without removing the air inlet sleeve.
Innovation Solution
A fan casing design with an annular flange featuring a setback in its thickness and bolts that pass through the flange axially, allowing equipment to be installed and removed without degrading the composite material's strength, eliminating the need for festoons in the air inlet sleeve flange.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If festoons are made in the flange of the air inlet sleeve to enable equipment removal, then equipment accessibility is improved, but the circumferential mechanical strength of the composite material air inlet sleeve is weakened
Solution Approach 1:
The invention moves the setback feature from the air inlet sleeve flange to the fan casing flange, changing the spatial location where the structural modification occurs. This allows equipment fastening to be accomplished through the fan casing flange rather than requiring festoons in the air inlet sleeve, thus preserving the air inlet sleeve's circumferential strength while maintaining equipment accessibility.
Solution Approach 2:
The invention extracts the equipment fastening function from the air inlet sleeve flange and relocates it to the fan casing flange. By providing setbacks in the fan casing flange, the fastening operation is separated from the air inlet sleeve structure, eliminating the need to compromise the air inlet sleeve's structural integrity.
2Ease of operation
If bolts pass through the fan casing flange for equipment fastening, then equipment installation and removal becomes independent of air inlet sleeve removal, but the flange structure becomes more complex
Solution Approach 1:
The invention segments the fastening system into two independent parts: setbacks in the fan casing flange for equipment fastening bolts, and the air inlet sleeve flange for connecting the air inlet sleeve to the fan casing. This segmentation allows equipment to be fastened and removed independently without affecting the air inlet sleeve connection, achieving operational independence while keeping each flange's structure relatively simple.
Data Source
AI summary
The invention provides a fan casing for a gas turbine engine, the casing having a substantially cylindrical portion that terminates at one end in an annular flange made of composite material. The flange includes at least one setback in a fraction of its thickness and at least one bolt for fastening pieces of equipment passing right through the flange in the axial direction, the bolt for fastening pieces of equipment having a head that presents a flat that is to bear flat against a rim of the setback, and a shank forming a stud for fastening pieces of equipment on the casing.