Gas Turbine Bleed Valve Dual-Stage Flow Modulation
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Solution Overview
Problem
Existing bleed valves in gas turbine engines extract air in stepped increments, leading to reduced engine efficiency and increased noise, as opening fewer valves results in inadequate bleed air and higher noise levels.
Innovation Solution
A bleed valve design with two stages of flow area modulation, controlled by a controller to equalize pressure drop across both stages, allowing for continuous or discrete variable flow area adjustment, and potentially active or passive control, reducing noise and improving efficiency by minimizing air extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple bleed valves are opened in parallel to extract sufficient bleed air, then the required amount of bleed air is achieved, but the noise generated by the bleed valves increases and engine efficiency is reduced
Solution Approach 1:
The single bleed valve is segmented into two sequential stages (first stage valve member and second stage valve member), allowing the flow modulation function to be divided across multiple components in series rather than relying on multiple parallel valves, thereby reducing the total number of valves needed and the associated noise
Solution Approach 2:
The bleed valve employs dynamic control of flow area through two stages of valve members that can be independently actuated, enabling continuous adjustment of the bleed air extraction amount to match exact engine requirements rather than using fixed stepped increments, thereby minimizing both air extraction and noise generation
2Quantity of substance
If multiple bleed valves are opened in parallel to extract sufficient bleed air, then the required amount of bleed air is achieved, but engine efficiency is reduced due to excessive air extraction
Solution Approach 1:
The bleed valve employs dynamic control of flow area through two stages of valve members that can be independently actuated, enabling continuous adjustment of the bleed air extraction amount to match exact engine requirements rather than using fixed stepped increments, thereby minimizing both air extraction and noise generation
Solution Approach 2:
The invention changes the control parameter from discrete stepped positions to continuous variable flow area adjustment, allowing precise matching of bleed air extraction to engine needs and avoiding excessive air extraction that would reduce engine efficiency
3Device complexity
If a single bleed valve is used with limited flow area adjustment, then the device complexity is reduced, but the precision of bleed air extraction control is insufficient
Solution Approach 1:
The single bleed valve is segmented into two sequential stages (first stage valve member and second stage valve member), allowing the flow modulation function to be divided across multiple components in series rather than relying on multiple parallel valves, thereby reducing the total number of valves needed and the associated noise
Solution Approach 2:
The invention merges the control functions of two valve members into a single integrated bleed valve assembly with unified actuation, achieving precise continuous flow control without the complexity of multiple independent valve systems
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The bleed valve design achieves quieter operation and improved engine efficiency by allowing precise control of air extraction, minimizing the amount of air bled and equalizing pressure drops across stages, thus reducing noise and maintaining engine performance.
Implementation Method 1
a controller to control the modulation of the flow area of at least one of the first stage and second stage, wherein the controller is configured to equalise the pressure drop across the first stage and the second stage
Data Source
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AI summary
A bleed valve for a gas turbine engine, the bleed valve comprising: an inlet coupled to an air source; and an outlet coupled to an air sink. The bleed valve also comprises a first stage of flow area modulation between the inlet and the outlet. Also a second stage of flow area modulation between the first stage and the outlet. The pressure can be equalised between the first and second stages. There is also an arrangement comprising a plurality of bleed valves and a controller to control the flow areas of at least one of the first and second stages of each bleed valve.