Fan Variable Area Nozzle Cam Drive Ring Actuation
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Solution Overview
Problem
Conventional gas turbine engines have fixed geometry fan nozzles that are inefficient for varying thrust conditions, and existing fan variable area nozzles are heavy due to complex mechanisms, which negates fuel efficiency gains.
Innovation Solution
A lightweight fan variable area nozzle system with a flap assembly, actuator system, and cam drive ring that symmetrically and asymmetrically adjusts the fan nozzle exit area and thrust vector, using a multiple of flaps and movable cams to optimize thrust and fuel efficiency across different flight conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If existing fan variable area nozzles are implemented, then fuel efficiency is improved through optimized thrust for different flight conditions, but device weight increases due to complex mechanisms
Solution Approach 1:
The nozzle is divided into multiple independent flaps (first flap, second flap, third flap, fourth flap) that can move separately along the bypass flow path. Each flap is controlled by its own actuator, allowing independent adjustment of nozzle area. This segmentation enables precise control of thrust characteristics for different flight conditions while using simpler, lighter individual actuators compared to a monolithic control mechanism.
Solution Approach 2:
The nozzle area is made dynamically adjustable through actuators that move the flaps between different positions (first position for takeoff, second position for cruise). The system transitions from a fixed geometry nozzle to a variable geometry nozzle with real-time adaptability, optimizing fuel efficiency across the entire flight envelope without requiring excessive structural weight.
2Device complexity
If conventional fixed geometry fan nozzles are used, then device complexity is minimized, but fuel efficiency deteriorates due to inability to optimize thrust for varying flight conditions
Solution Approach 1:
The nozzle is divided into multiple independent flaps (first flap, second flap, third flap, fourth flap) that can move separately along the bypass flow path. Each flap is controlled by its own actuator, allowing independent adjustment of nozzle area. This segmentation enables precise control of thrust characteristics for different flight conditions while using simpler, lighter individual actuators compared to a monolithic control mechanism.
Solution Approach 2:
The nozzle area is made dynamically adjustable through actuators that move the flaps between different positions (first position for takeoff, second position for cruise). The system transitions from a fixed geometry nozzle to a variable geometry nozzle with real-time adaptability, optimizing fuel efficiency across the entire flight envelope without requiring excessive structural weight.
3Productivity
If fan variable area nozzles with complex mechanisms are implemented, then thrust optimization for different flight conditions is achieved, but overall engine weight increases to the extent that fuel efficiency gains are negated
Solution Approach 1:
The nozzle is divided into multiple independent flaps (first flap, second flap, third flap, fourth flap) that can move separately along the bypass flow path. Each flap is controlled by its own actuator, allowing independent adjustment of nozzle area. This segmentation enables precise control of thrust characteristics for different flight conditions while using simpler, lighter individual actuators compared to a monolithic control mechanism.
Solution Approach 2:
The nozzle area is made dynamically adjustable through actuators that move the flaps between different positions (first position for takeoff, second position for cruise). The system transitions from a fixed geometry nozzle to a variable geometry nozzle with real-time adaptability, optimizing fuel efficiency across the entire flight envelope without requiring excessive structural weight.
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 system provides effective, lightweight thrust vectoring and fuel-efficient operation by varying the fan nozzle exit area and thrust direction, enhancing performance during take-off, cruise, and landing conditions while minimizing weight and complexity.
Implementation Method 1
The actuator system rotationally translates a cam drive ring which drives the flap linkage of each flap to symmetrically vary the fan nozzle exit area. In operation, a multiple of actuators rotate the cam drive ring which results in a follower of the flap linkage following a cam surface to pivot each flap
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
A fan variable area nozzle (FVAN) (42) includes a flap assembly which varies a fan nozzle exit area through a cam drive ring (58). The flap assembly generally includes a multiple of flaps (50), flap linkages (52) and an actuator system (54). The actuator system (54) rotationally translates the cam drive ring (58) relative an engine centerline axis which results in a follower of the flap linkage (52) following a cam surface (86) to pivot each flap (50) such that the flap assembly dilates about the circumferential hinge line. Rotation of the cam drive ring (58) adjusts dilation of the entire fan nozzle exit area in a symmetrical manner. Another cam drive ring (58' Fig 5A) includes a multiple of movable cams (84) which engages the follower of the flap linkage (52) of each flap (50) such that pivotable movement of a particular number of the multiple of movable cams (84) about a respective cam pivot results in vectoring of the FVAN (42).