Outer Premix Barrel Vent Air Sweep for Fuel Accumulation
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Solution Overview
Problem
Fuel accumulation on or adjacent to injector surfaces in gas turbine engines can lead to auto-ignition or flame holding, which reduces efficiency and increases maintenance costs.
Innovation Solution
A gas turbine engine outer premix barrel with truncated wedge-shaped vanes and vent passages that sweep away accumulated fuel, preventing auto-ignition and facilitating easier maintenance by being removable for overhaul.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fuel accumulates on injector surfaces, then flame holding occurs, but engine efficiency decreases and maintenance costs increase
Solution Approach 1:
The patent applies preliminary action by introducing vent air through vent passages in the vanes before fuel accumulation can cause auto-ignition. The vent air sweep continuously prevents fuel from accumulating on the inward surfaces of the vanes, eliminating the harmful effect before it occurs. This is evident in the description where vent passages are provided in the vanes to allow vent air to sweep across inward surfaces and prevent fuel accumulation.
2Reliability
If vent passages are added to vanes, then fuel sweep capability improves, but device complexity increases
Solution Approach 1:
The patent applies universality by making the outer premix barrel removable and replaceable, allowing it to serve multiple functions: it acts as both a structural component and a maintenance module. The barrel can be removed as a single unit for overhaul, and the vanes can be replaced independently if needed. This is supported by the claims stating the outer premix barrel is removable from the injector head and can be overhauled separately.
Solution Approach 2:
The patent applies segmentation by dividing the outer premix barrel into separable components - the barrel itself, the vanes, and the barrel end. This allows individual components to be inspected, cleaned, or replaced independently. The vanes can be removed from the barrel for separate maintenance, and the barrel end can be separated for specific repairs, reducing overall device complexity while maintaining fuel sweep capability.
3Ease of repair
If the outer premix barrel is made removable, then maintenance ease improves, but connection reliability may decrease
Solution Approach 1:
The patent applies preliminary action by providing thread holes and threaded fasteners in advance during manufacturing. The thread holes are pre-formed in the outer premix barrel, and threaded fasteners are provided for securing the barrel to the injector head. This preliminary preparation ensures that the removable connection can be quickly and reliably reassembled during maintenance, maintaining connection reliability while enabling easy removal for overhaul.
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 effectively prevents auto-ignition and flame holding, enhances engine efficiency, reduces emissions, and lowers maintenance costs by ensuring fuel is swept away from low-pressure areas, thereby extending the life of injector components.
Implementation Method 1
Each vent passage is in flow communication with at least one vent air inlet... the vent passages may sweep away fuel that may collect in a low pressure area adjacent inward surface
Data Source
AI summary
A gas turbine engine outer premix barrel is disclosed. The outer premix barrel includes a body portion, a barrel portion, and a plurality of vanes. The body portion includes vent air inlets. The barrel portion extends axially aft from the body portion. The plurality of vanes extends axially forward from the body portion. Each vane includes an inward surface located at a radially inner end of the vane, and a plurality of vent passages exiting the vane at the inward surface. Each vent passage is in flow communication with at least one vent air inlet.