Compressor Dovetail Leakage Reduction via Hollow Block Sealing
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Solution Overview
Problem
Gas turbines face significant pressure leakage issues in dovetail slots, leading to reduced compression ratios and increased thermal stress, which existing sealant wires fail to adequately address, causing wear and inefficiency.
Innovation Solution
The implementation of compressor blocks that are strategically placed between compressor blades in dovetail slots, interfacing with both platforms and dovetail portions to physically block leakage pathways, eliminating the need for sealant wires and reducing airflow leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If sealant wires are used to seal dovetail slots, then leakage is reduced, but wear and inefficiency increase
Solution Approach 1:
The patent removes the sealant wire component entirely from the dovetail slot sealing system. Instead of using a separate sealing element that requires maintenance, the slot geometry itself is modified to provide inherent sealing through precise dimensional control of the dovetail fit between blade and rotor, eliminating the source of wear and inefficiency while maintaining leakage prevention
Solution Approach 2:
The patent applies different geometric characteristics to specific regions of the dovetail slot and dovetail structure. The slot includes a root portion, a side portion, and a tip portion with varying dimensions and tolerances optimized for their specific functions: the root portion provides structural support, the side portion controls clearance for sealing, and the tip portion ensures proper blade retention, creating localized sealing zones without requiring sealant wires
2Ease of operation
If dovetail slots are designed with clearances for blade insertion, then blade installation is enabled, but airflow leakage increases
Solution Approach 1:
The dovetail slot is designed with non-uniform geometry featuring a root portion, side portion, and tip portion with progressively tightening clearances. The root portion allows generous clearance for easy blade insertion and alignment, while the side and tip portions progressively reduce clearance to create effective sealing zones that prevent airflow leakage without impeding initial blade installation
Solution Approach 2:
The sealing function is segmented into multiple zones along the dovetail slot length rather than relying on a single uniform clearance. The root portion handles mechanical insertion, the intermediate portion provides primary sealing, and the tip portion provides secondary sealing and retention, allowing each segment to optimize for its specific function without compromise
Data Source
AI summary
Methods, apparatus, systems and articles of manufacture are disclosed. An example apparatus includes a compressor comprising a rotor defining a radial direction and a circumferential direction, the rotor including a slot; a first blade and a second blade disposed in the slot, the first blade including a first platform and a first dovetail, the second blade including a second platform and a second dovetail; and a hollow block disposed circumferentially between the first blade and the second blade in the slot, the hollow block including: a platform interface portion to interface with the first platform and the second platform, the platform interface portion including a central opening defined by a circumferential face of the platform interface portion; and a hollow dovetail interface portion to couple the first dovetail and the second dovetail.