Variable-Pitch Radial Stator Vanes for Bypass Turbine Engine Mass Reduction
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Solution Overview
Problem
Turbine engines with high bypass ratios face issues of increased mass and drag due to larger secondary duct dimensions, leading to higher fuel consumption and acoustic noise, as well as the need for complex thrust reversers and fixed stator vanes that add weight and complexity.
Innovation Solution
Incorporating variable-pitch radial stator vanes upstream of the movable fan to deflect axial air flows, eliminating the need for downstream stator vanes and allowing for adaptive pitch adjustments to optimize air flow and reduce noise, thereby reducing engine mass and complexity while maintaining high bypass ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the dimensions of the secondary duct are increased to achieve high bypass ratio, then the thrust and fuel efficiency are improved, but the mass and drag of the engine are increased
Solution Approach 1:
The patent inverts the conventional arrangement by placing stator vanes upstream of the movable fan instead of downstream. This upstream positioning allows the stator vanes to pre-condition the airflow before it reaches the fan, enabling the fan to operate more efficiently and generate the required thrust with a smaller secondary duct, thereby reducing engine mass while maintaining fuel efficiency
Solution Approach 2:
The stator vanes perform preliminary action by deflecting and conditioning the airflow upstream of the movable fan. This pre-conditioning of the airflow allows the fan to operate at optimal angles, improving its efficiency in generating thrust while reducing the need for a large secondary duct, thus reducing overall engine mass
2Force
If the dimensions of the secondary duct are increased to achieve high bypass ratio, then the thrust is improved, but the drag is increased
Solution Approach 1:
By inverting the conventional arrangement and placing stator vanes upstream of the fan, the patent enables more efficient airflow conditioning that allows for a smaller secondary duct diameter. This reduces the wetted area and form drag on the engine while maintaining the high bypass ratio and thrust generation capability
3Ease of operation
If fixed stator vanes are installed in the secondary duct downstream of the movable fan, then the airflow rectification is improved, but the device complexity and mass are increased
Solution Approach 1:
The patent inverts the conventional arrangement by placing stator vanes upstream of the movable fan instead of downstream in the secondary duct. This upstream positioning provides effective airflow rectification and conditioning before the fan, eliminating the need for additional fixed stator vanes downstream, thereby reducing device complexity and mass
Solution Approach 2:
The upstream stator vanes perform multiple functions: they deflect the incident axial airflow, pre-condition it for optimal fan operation, and provide airflow rectification that would traditionally require separate downstream components. This multi-functionality reduces the overall number of parts and simplifies the engine design
4Force
If the diameter of the outer casing is increased to accommodate high bypass ratio, then the thrust is improved, but the acoustic noise is increased
Solution Approach 1:
By inverting the conventional arrangement and placing stator vanes upstream of the fan, the patent enables a smaller secondary duct diameter to achieve the same thrust. This reduced diameter decreases the acoustic noise generated by the engine while maintaining high bypass ratio and thrust performance
Solution Approach 2:
The upstream stator vanes perform preliminary airflow conditioning that optimizes the flow entering the fan. This reduces turbulence and flow irregularities that would otherwise generate acoustic noise, allowing for a smaller, quieter engine design while maintaining thrust performance
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 reduces engine mass and complexity, limits acoustic noise, and allows for efficient thrust generation with reduced fuel consumption by optimizing air flow and eliminating the need for thrust reversers, while maintaining high bypass ratios.
Implementation Method 1
the variable-pitch radial vanes being configured to deflect the incident axial air and the movable fan being configured to axially rectify said air deflected in the secondary duct
Implementation Method 2
a movable fan 2 for compressing an incident air flow F, the movable fan 2 comprising radial blades 20 of which the free ends face the outer casing 13 of the turbine engine 1 so as to compress an air flow at least in the secondary duct V2
Data Source
AI summary
A bypass turbine engine including an inner casing, an inter-duct casing and an outer casing, wherein a primary duct is defined between the inter-duct casing and the inner casing, wherein a secondary duct is defined between the inter-duct casing and the outer casing wherein a rotary shaft includes, at the upstream end, a movable fan including radial blades of which the free ends face the outer casing of the turbine engine so as to compress an air flow at least in the secondary duct, wherein a plurality of variable-pitch radial stator vanes are mounted upstream of the movable fan, the variable-pitch vanes being configured to deflect the incident axial air, wherein the movable fan is configured to axially rectify the air deflected in the secondary duct, and the turbine engine not being provided with stator vanes in the secondary duct downstream of the movable fan.