Self-Cooling Active Combustion Control Valve for Low Flow Modulation
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Solution Overview
Problem
Existing active combustion control valves lack the necessary flow modulation control authority at low fuel flow rates due to their location away from the harsh thermal environment of fuel injectors, limiting their effectiveness in suppressing thermo-acoustic instabilities in gas-turbine combustors.
Innovation Solution
A small, robust, self-cooling active combustion control valve with a core valve housing, actuator, and valve seat, capable of modulating fluid flow in response to electrical signals, is designed to operate in close proximity to the fuel injector, allowing precise control of fluid flow even at low flow rates and high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If large valves are used to modulate the entire fuel flow to the main combustor, then flow modulation control is adequate, but the valve must be located in a benign environment which limits flow control authority for low flow rates
Solution Approach 1:
The fuel flow control system is segmented into two independent valves: a large valve for main combustor flow control located in a benign environment, and a small ACCV for low-flow modulation control located near the fuel injector in the harsh thermal environment. This segmentation allows each valve to be optimized for its specific function and location requirements.
Solution Approach 2:
The small ACCV acts as an intermediary device that supplements the main valve's control capability at low flow rates. By positioning this smaller valve close to the fuel injector, it provides the necessary control authority in the harsh thermal environment where the main valve cannot operate effectively.
2Ease of operation
If the control valve is located far from the harsh thermal environment of a fuel injector, then the valve can operate properly, but flow control authority for low flow rates is limited
Solution Approach 1:
The system divides the control function between two valves positioned at different locations: the main valve remains in the benign environment for reliable operation, while a segmented small ACCV is placed near the fuel injector to provide local control authority where it is most needed.
Solution Approach 2:
Different parts of the control system have different operational requirements. The main valve operates in a benign environment with relaxed control requirements, while the small ACCV is specifically designed with local quality features (smaller size, different actuation mechanism) to operate effectively in the harsh thermal environment close to the fuel injector.
3Reliability
If a small control valve is designed to operate in severe thermal environment, then flow control authority at low flow rates is improved, but the valve must be robust and self-cooling
Solution Approach 1:
The small ACCV is designed as a self-cooling valve where the fuel flow passing through it serves to cool the valve components from the inside. This self-service cooling mechanism eliminates the need for external cooling systems, maintaining robustness while operating in severe thermal environments exceeding 1,200°F.
Solution Approach 2:
The harsh thermal environment that would normally be harmful to the valve is converted into a benefit through the self-cooling design. The hot fuel flow, which could damage the valve, instead serves as the cooling medium, and the valve's positioning in the harsh environment is precisely where control authority is most needed.
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 valve achieves excellent control authority at low flow rates, suppressing thermo-acoustic instabilities and maintaining engine efficiency while withstanding severe thermal environments, ensuring reliable operation even in temperatures exceeding 1,200°F.
Implementation Method 1
sensing the amplitudes and frequencies of acoustic pressure waves and then modulating fuel injection at a frequency which dampens the naturally occurring thermo-acoustic instabilities
Implementation Method 2
a passageway in fluid communication with the core valve housing and the valve seat... directing fluid along at least a portion of the core housing for cooling
Data Source
AI summary
Various examples of an active combustion control valve, combustion systems, and method of controlling the flow of liquid fluid in a gas combustion system are described. In one aspect of the present invention, an active combustion control valve includes a core valve housing, an actuator, a valve seat in communication with the actuator, and a passageway in fluid communication with the core valve housing and the valve seat. The control valve is responsive to change in voltage applied to the actuator and is capable of a first condition permitting a first fluid flow through the passageway and a second condition permitting a second fluid flow through the passageway, the first fluid flow being different than the second fluid flow. The combustion control valve is small, robust, responsive and self-cooling to operate in severe thermal environment.