Fan Hub Pump Injection for Gas Turbine Flow Control
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Solution Overview
Problem
Current turbofan gas turbine engine designs face inefficiencies in flow management, leading to reduced performance and increased vibration and noise due to flow separation issues around fan blades, which are not adequately addressed by existing mechanical energy distribution methods.
Innovation Solution
A fan assembly with a nose cone and integrated pump that uses ambient air to drive injection air into the flow passage defined by the fan blades and hub, influencing flow characteristics by directing pressurized air through injection passages to specific locations, such as the root region of the fan blades, thereby delaying flow separation and improving overall engine performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If high-pressure air is routed from the compressor to control fan flow, then flow control capability is improved, but device complexity and routing complexity increase
Solution Approach 1:
The invention extracts the flow control function from the compressor system and relocates it to the fan assembly. A pump is integrated into the fan hub that draws ambient air from the nose cone and injects it directly at the fan blade roots, eliminating the need for complex high-pressure air routing from the compressor while maintaining flow control capability
Solution Approach 2:
The pump integrated into the fan hub acts as an intermediary device that uses ambient air as a working fluid to achieve flow control. Instead of using high-pressure air from the compressor, the system uses the pump to pressurize and inject ambient air at critical locations, simplifying the overall system architecture
2Productivity
If mechanical energy from the gas turbine is used to accelerate air, then propulsion efficiency is improved, but flow separation and vibration occur
Solution Approach 1:
The system performs preliminary action by injecting air at the fan blade roots before the main flow develops. The pump delivers injection air to the root region of the fan blades, which modifies the boundary layer and delays flow separation before it can occur, allowing the fan to operate more efficiently across a broader range of conditions
Solution Approach 2:
The invention changes the flow parameters by injecting pressurized air at the fan blade roots, which modifies the boundary layer characteristics and delays flow separation. This parameter change allows the fan to maintain attached flow at higher angles of attack, improving propulsion efficiency and expanding the operating range
3Productivity
If injection air is delivered to the fan blade root region, then flow separation is delayed and performance is improved, but additional components are required
Solution Approach 1:
The pump is merged with the fan hub structure, integrating the flow control function directly into the existing fan assembly. The pump, injection passages, and collection chamber are all incorporated into the fan hub, eliminating the need for separate external components and reducing overall system complexity while enabling injection air delivery to the fan blade roots
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
This solution enhances the operating range and efficiency of the turbofan engine by reducing fan vibration stress and noise, while also reducing the need for complex high-pressure air routing from the compressor, leading to improved flow control and performance.
Implementation Method 1
a pump at least partially housed in the interior of the nose cone, the pump being configured to, using the ambient air in the nose cone, drive injection air into the flow passage
Implementation Method 2
The pump may comprise a plurality of rotor blades secured for common rotation with the fan
Data Source
AI summary
Assemblies and methods for providing injection air to influence flow in a flow passage defined by a fan of a gas turbine engine are disclosed. In one embodiment, the method comprises: receiving air into an interior of a nose cone; increasing the pressure of the air in the interior of the nose cone and directing the pressurized air; and discharging the air into the flow passage defined by the fan.