Compressor Casing Treatment With Movable Ring Stall Control
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Solution Overview
Problem
Existing gas turbine engine compressors face efficiency degradation and compressor stall due to blade-tip clearance, with conventional casing treatments becoming inefficient or counterproductive outside high-load conditions.
Innovation Solution
A movable ring system with adjustable slots and openings in the compressor casing allows dynamic control of the casing treatment, enabling activation or deactivation based on operating conditions, using mechanisms like springs, actuators, or camshafts to manage airflow and prevent stall while maintaining efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If casing treatment slots are opened to prevent compressor stall under high load, then compressor stall prevention is improved, but compressor efficiency deteriorates when operating outside high-load conditions
Solution Approach 1:
The patent applies the dynamics principle by implementing a movable ring that can shift axially to dynamically open or close the casing treatment slots based on operating conditions. The ring is positioned to close the slots during normal operation to maintain efficiency, and can be moved to open the slots when compressor stall prevention is required, allowing the system to adapt its configuration in real-time
Solution Approach 2:
The patent applies parameter changes by modifying the state of the casing treatment slots from fixed open/closed configurations to a dynamically controllable state. The movable ring enables change in the geometric parameter of slot openness, transitioning between closed (for efficiency) and open (for stall prevention) states based on operational requirements
2Reliability
If conventional casing treatment slots are permanently open to prevent stall, then compressor stall prevention is improved, but compressor efficiency is degraded during normal operation
Solution Approach 1:
The movable ring transforms the static casing treatment into a dynamic system where the slots can be opened or closed based on real-time operating conditions, allowing the compressor to maintain high efficiency during normal operation while providing stall prevention capability when needed
3Reliability
If casing treatment is activated to control blade tip flow, then compressor stall margin is improved, but device complexity increases due to movable ring mechanism
Solution Approach 1:
The movable ring acts as an intermediary element between the compressor casing and the slots, providing a simple mechanical means to control slot openness. This intermediary component enables complex functionality (dynamic slot control) through a relatively simple structural addition
Data Source
AI summary
Casing of a gas turbine engine compressor comprising openings cut in the thickness of the casing from an inner surface of the casing and arranged side by side over a circumference of the casing, characterised in that it also comprises a movable ring, formed by at least two annular portions, positioned on an outer surface of the casing opposite the openings and able to move along the circumference of the casing such as to open and close the openings of the casing to activate or deactivate a casing treatment, the movable ring comprising the same number of slots as there are openings in the casing.