Sheared Exhaust Nozzle for Thrust Vector Alignment
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Solution Overview
Problem
Commercial aircraft face challenges in fuel efficiency and noise reduction, particularly during high-power operations, due to increased fuel prices and noise restrictions, which existing exhaust systems fail to adequately address.
Innovation Solution
The exhaust system incorporates a nacelle with a curved portion that shifts exhaust gas towards the engine's longitudinal axis, counteracting deflection caused by the pylon attachment, thereby reducing community noise and improving fuel efficiency by aligning the thrust vector in an aft direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the nacelle is attached to the aircraft using a pylon, then the engine can be mounted on the wing or fuselage, but the pylon causes deflection of the exhaust gas away from the longitudinal axis of the engine
Solution Approach 1:
The curved portion of the exhaust nozzle is designed in advance to counteract the deflection effect of the pylon. The curvature is specifically tailored to pre-position the exhaust flow so that when deflected by the pylon, the exhaust gas returns to alignment with the longitudinal axis of the engine, thereby eliminating thrust vector distortion and energy loss.
2Device complexity
If the exhaust gas is allowed to deflect freely, then the structure is simpler, but community noise increases and fuel efficiency decreases
Solution Approach 1:
A curved portion is introduced into the exhaust nozzle structure to redirect the exhaust flow. This curvature modifies the flow path of the exhaust gas, ensuring it realigns with the longitudinal axis after being deflected by the pylon, thereby reducing jet noise and improving fuel efficiency without significantly complicating the overall nozzle design.
3Object-generated harmful factors
If a curved portion is added to the exhaust nozzle to counteract pylon deflection, then noise and fuel efficiency improve, but the device complexity increases
Solution Approach 1:
Instead of redesigning the entire exhaust nozzle, the curvature is applied locally to a specific portion of the nozzle where it is most effective in counteracting pylon deflection. This localized modification achieves the desired flow realignment and noise reduction while minimizing the increase in overall device complexity.
4Use of energy by moving object
If the exhaust nozzle is designed with curvature to align thrust vector, then fuel efficiency improves, but manufacturing precision requirements increase
Solution Approach 1:
The curvature of the exhaust nozzle is optimized by adjusting geometric parameters such as the angle and radius of the curved portion. These parameter changes are designed to achieve the desired thrust vector alignment and fuel efficiency improvement while remaining within feasible manufacturing tolerances and production capabilities.
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 enhances thrust vector alignment and reduces jet noise, leading to improved fuel efficiency and noise reduction downstream of the engine, while maintaining aerodynamic performance and minimizing drag.
Implementation Method 1
the IFS and the OFS shift exhaust gas exiting the exhaust towards a longitudinal axis of the engine so as to fill an area behind the engine and counteract deflection of the exhaust gas caused by a pylon attached to the nacelle
Data Source
AI summary
Conventional commercial engine exhaust systems are defined with axi-symmetric surfaces (e.g., conical or nearly conical surfaces), which create an annular exhaust for the fan (bypass) nozzle of roughly constant duct-height around the circumference. In one example configuration, the fan sleeve has been sheared upward (towards the wing or pylon) causing a larger area and duct height near the pylon relative to the portion away from the pylon. For a given thrust generated by the turbofan engine housed in the nacelle, the shear toward the pylon mount realigns the thrust in the direction of flight which may, in some examples, reduce noise experienced downstream of the turbofan engine and decreases fuel consumed in the engine core.