Split Aerofoil Fan Blade Reverse Pitch Mechanism
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Solution Overview
Problem
Traditional gas turbine engine thrust reverse systems are heavy and complex, and using a variable pitch fan for thrust reversal can starve the engine core of air, requiring additional complex components to maintain airflow during reverse thrust operations.
Innovation Solution
A gas turbine engine fan blade apparatus with a split aerofoil part, where one portion can rotate to a reverse pitch configuration while the other remains in a forward pitch configuration, reducing adverse airflow impact on the core and allowing more efficient airflow during reverse thrust modes, and a variable pitch rotatable mounting for additional control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional blocker doors and translatable cowling are used for thrust reverse, then reverse thrust functionality is achieved, but weight and complexity increase considerably
Solution Approach 1:
The fan blades are designed to perform multiple functions: normal propulsion and reverse thrust. By making the fan blades themselves adjustable in pitch, the system eliminates the need for separate thrust reverse mechanisms (blocker doors and translatable cowling), thereby reducing complexity while maintaining reverse thrust capability
Solution Approach 2:
The thrust reverse function is merged with the fan blade structure itself. Instead of having separate components for thrust reversal, the pitch adjustment mechanism is integrated into the fan blades, combining propulsion and reverse thrust functions into a single system
2Device complexity
If variable pitch fan is used for thrust reverse, then separate thrust reverser equipment can be omitted, but the core of the engine is starved of air via the conventional route
Solution Approach 1:
The fan blade aerofoil is divided into two separate portions: a radially inner portion and a radially outer portion. This segmentation allows independent pitch control of each portion, enabling the inner portion to maintain forward pitch for core airflow while the outer portion reverses for thrust reversal
Solution Approach 2:
Different portions of the fan blade are given different pitch configurations to serve different functions. The radially inner portion maintains forward pitch to preserve core airflow, while the radially outer portion adopts reverse pitch for thrust reversal, allowing each part to have optimized local characteristics
3Quantity of substance
If variable bypass nozzle and variable core inlet geometry are added to maintain airflow during reverse thrust, then core airflow is maintained, but complex and heavy components are reintroduced
Solution Approach 1:
The fan blade is segmented into radially inner and outer portions that can be independently pitched. This segmentation eliminates the need for additional complex components like variable bypass nozzles and variable core inlet geometry, as the segmented blade design itself manages both thrust reversal and core airflow requirements
Solution Approach 2:
The segmented fan blade structure serves multiple functions simultaneously: it provides thrust reversal through outer portion pitch reversal while maintaining core airflow through inner portion forward pitch, eliminating the need for separate dedicated components for each function
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 design reduces turbulence and maintains efficient airflow to the core during reverse thrust operations, potentially eliminating the need for separate thrust reverser technology by minimizing weight and complexity.
Implementation Method 1
an aerofoil part, the aerofoil part comprising radially inner and radially outer portions that are separated by an interface extending from a leading edge of the aerofoil part to a trailing edge of the aerofoil part
Implementation Method 2
the reverse pitch rotatable mounting and separation at the interface permit relative pitch change rotation between the radially inner and radially outer portions
Data Source
AI summary
A gas turbine engine fan blade apparatus is disclosed comprising a reverse pitch rotatable mounting and an aerofoil part. The aerofoil part comprises radially inner and radially outer portions that are separated by an interface extending from a leading edge of the aerofoil part to a trailing edge of the aerofoil part. The reverse pitch rotatable mounting locates the radially inner and radially outer portions with respect to one another. The reverse pitch rotatable mounting and separation at the interface permit relative pitch change rotation between the radially inner and radially outer portions such that one of the radially inner and radially outer portions is rotatable to a reverse pitch configuration by comparison with the other portion.