Turbofan Fan Blade Modification for Aeroderivative Conversion
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Solution Overview
Problem
Conventional methods for converting turbofan gas turbines to aeroderivative engines for electrical power generation are time-consuming and require extensive testing, with many changes to the original hardware and the need for new parts, leading to increased development time and costs.
Innovation Solution
The method involves modifying the fan of a turbofan engine to reduce bypass flow, allowing the low-pressure turbine to generate excess shaft power by reducing the outer diameter or removing radial portions of the fan blades, and optionally modifying the geometry to achieve a reduced bypass thrust, thereby enabling efficient conversion with minimal hardware changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the conventional approach is used to convert a turbofan engine to a turbojet engine by replacing the fan and bypass system with additional compressors and exhaust nozzle, then the engine can generate shaft power for electrical power generation, but the development time and cost increase significantly due to extensive hardware changes and testing requirements
Solution Approach 1:
The patent changes the operational parameters of the existing fan by modifying its blade geometry (pitch angle, chord length, or twist distribution) to alter the bypass flow ratio. This allows the fan to operate in a new regime that generates excess shaft power at the low-pressure turbine without requiring fundamental hardware changes or extensive retesting, thus reducing development time while maintaining conversion capability
Solution Approach 2:
The patent makes the existing fan serve multiple functions: it continues to provide bypass flow for thrust generation while simultaneously operating as a power-generating component by driving the low-pressure turbine. This multi-functionality eliminates the need for separate compressor systems and reduces the overall complexity of conversion, thereby reducing development time and testing requirements
2Power
If the conventional approach is used to convert a turbofan engine, then shaft power can be generated for electrical power generation, but the number of new parts and hardware changes increases, leading to increased manufacturing complexity and cost
Solution Approach 1:
Instead of adding new compressor hardware, the patent modifies the existing fan blade parameters (geometry, pitch, or configuration) to change its aerodynamic characteristics. This allows the fan to generate excess power at the low-pressure turbine while minimizing the number of new parts required, thereby reducing manufacturing complexity and cost
Solution Approach 2:
The patent extracts and utilizes the excess power potential already present in the existing fan-low-pressure turbine system by adjusting operational parameters. Rather than adding new power-generating components, it extracts additional shaft power from the modified fan's operation, reducing the need for new hardware and simplifying the conversion process
3Power
If the fan is modified to reduce bypass flow, then excess shaft power is generated at the low-pressure turbine for electrical power generation, but the bypass thrust is reduced
Solution Approach 1:
The patent modifies fan blade parameters (such as pitch angle or chord length) to optimize the balance between bypass flow and power generation. By carefully adjusting these parameters, the fan can operate at a configuration that generates sufficient excess shaft power for electrical generation while maintaining adequate bypass thrust for engine operation, thus resolving the trade-off between power generation and thrust production
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 approach significantly reduces development time, minimizes testing requirements, and reduces the need for new parts, allowing for efficient conversion of turbofan engines to aeroderivative engines with enhanced electrical power generation capabilities.
Implementation Method 1
a low pressure turbine that is in turn driven by the core engine
Implementation Method 2
the modified fan being configured for generating a reduced bypass flow with respect to said fan bypass flow during operation
Data Source
AI summary
A method for converting a turbofan engine including providing a turbofan engine and converting the turbofan engine. The turbofan engine includes a core engine (including at least one high pressure spool assembly and a combustion chamber), and an unmodified fan configured for providing at least a bypass flow bypassing the core engine, the fan being mechanically coupled to a low pressure turbine that is in turn driven by the core engine. The conversion includes modifying or replacing the unmodified fan to provide a modified fan, the modified fan configured for generating a reduced bypass flow with respect to said fan bypass flow during operation of the converted turbofan engine corresponding to at least one set of engine conditions, enabling said low pressure turbine to generate an excess shaft power above a baseline shaft power required for driving the modified fan during operation of the converted turbofan engine.