Phase-Change Bleed Valve for Automatic Compressor Airflow Control
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Solution Overview
Problem
Existing gas turbine engines face challenges in efficiently controlling bleed airflow during startup and operation, particularly in single-use configurations where the bleed valve remains open, leading to inefficiencies and slower engine startup.
Innovation Solution
A bleed valve mechanism utilizing a phase change material, such as wax, to automatically transition from an open to a closed position based on temperature changes induced by bleed air flow, ensuring the valve is open during startup and closed post-startup, thereby optimizing airflow management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the bleed valve remains open during operation, then excess pressure is bled and impeller rotation is easier, but engine startup is slower and operational efficiency is reduced
Solution Approach 1:
The patent utilizes the phase transition of a material (from solid to liquid) in response to temperature changes caused by bleed air flow to automatically actuate the bleed valve from open to closed position. This eliminates the need for complex external control systems and enables automatic adaptation to engine operating conditions, resolving the contradiction between maintaining startup ease and improving operational efficiency.
2Ease of operation
If the bleed valve is manually controlled, then airflow can be precisely regulated, but system complexity and control requirements increase
Solution Approach 1:
The bleed valve system performs self-control through the automatic phase transition mechanism that responds to temperature changes from bleed air flow. The system self-regulates without external control inputs, eliminating complex control systems while maintaining appropriate valve positioning based on engine operating conditions.
Solution Approach 2:
The patent replaces complex mechanical or electronic control systems with a passive thermal-responsive phase transition mechanism. This substitution simplifies the overall control system while maintaining the ability to regulate airflow based on engine operating conditions.
3Loss of energy
If the bleed valve closes too early, then energy loss is reduced, but excess pressure buildup occurs in the compressor
Solution Approach 1:
The phase transition mechanism provides automatic feedback control based on temperature changes from bleed air flow. As bleed air flows through the system, it heats the phase change material, which transitions from solid to liquid, causing the valve to close. This feedback mechanism ensures the valve closes at the appropriate moment when temperature conditions indicate it is safe to do so, preventing both excessive energy loss and dangerous pressure buildup.
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 solution provides a cost-effective and reliable means to control bleed airflow, facilitating faster engine startup and efficient operation by automatically adjusting the bleed valve position in response to thermal changes, enhancing engine performance and efficiency.
Implementation Method 1
The movement of the valve element toward the closed position is driven by a phase change of a volume of phase change material positioned in the valve support between the valve support and the valve element
Implementation Method 2
The volume of phase change material is configured to be heated by a flow of bleed air directed past the bleed valve, and to change phase from solid to liquid via a heating
Data Source
AI summary
A compressor bleed valve of a gas turbine engine includes a valve support, and a valve element positioned at the valve support and movable relative to the valve support from an open position into a closed position engaged with a valve seat. The movement of the valve element toward the closed position is driven by a phase change of a volume of phase change material disposed in the valve support between the valve support and the valve element.