Turbofan Pre-cooler Fluid Propeller for Drag Reduction
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Solution Overview
Problem
Aircraft pre-coolers designed for maximum expected load may become undersized if engine pressure changes, leading to increased pylon size and aerodynamic drag, which is costly and affects performance.
Innovation Solution
A fluid propeller, such as an auxiliary compressor or ejector pump, is used to increase the flow rate of bleed air through the pre-cooler, enhancing pressure gradient and allowing an undersized pre-cooler to meet cooling demands without increasing pylon size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If pre-cooler size is increased to accommodate maximum expected load, then cooling capacity is improved, but pylon size and aerodynamic drag increase
Solution Approach 1:
The patent applies dynamics by making the bleed air flow rate variable through the use of a fluid propeller (auxiliary compressor or ejector pump). This dynamic adjustment allows the pre-cooler to adapt to varying cooling demands without requiring a larger fixed-size pre-cooler, thereby avoiding increased pylon size and aerodynamic drag while maintaining sufficient cooling capacity when needed.
Solution Approach 2:
The patent changes the parameter of bleed air flow rate by introducing a fluid propeller that actively controls the amount of bleed air passing through the pre-cooler. This parameter change enables an undersized pre-cooler to achieve adequate cooling performance by optimizing the flow rate rather than increasing the pre-cooler physical size, thus avoiding drag penalties.
2Object-affected harmful factors
If pre-cooler size is reduced when engine pressure changes, then pylon size and drag are minimized, but cooling capacity becomes insufficient
Solution Approach 1:
The fluid propeller dynamically adjusts the bleed air flow rate to match cooling demands, allowing a smaller pre-cooler to deliver adequate cooling capacity when required. This dynamic control resolves the contradiction between having a small pre-cooler (reducing drag) and providing sufficient cooling when needed.
Solution Approach 2:
The patent uses pneumatic principles through the fluid propeller (auxiliary compressor or ejector pump) to control and amplify the bleed air flow through the pre-cooler. This pneumatic mechanism enables a compact pre-cooler to achieve higher effective cooling capacity by optimizing the air flow characteristics rather than increasing physical size.
3Temperature
If bleed air flow rate is increased through pre-cooler, then cooling capacity is improved, but power extraction from engine increases
Solution Approach 1:
The patent employs pneumatic principles through the fluid propeller system that uses engine bleed air itself to drive the auxiliary compressor or ejector pump. This self-contained pneumatic system increases cooling capacity without requiring additional engine power extraction, as the fluid propeller is driven by the bleed air flow rather than by engine shaft power.
Solution Approach 2:
The fluid propeller system is self-driven by the bleed air flow it processes. The auxiliary compressor or ejector pump uses the kinetic energy of the bleed air to augment its own operation, creating a self-service mechanism that enhances cooling capacity without imposing additional fuel consumption penalties on the engine.
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 solution enables sufficient cooling without enlarging the pylon, minimizing aerodynamic drag and maintaining aircraft performance, with power extraction only affecting non-critical fuel consumption conditions.
Implementation Method 1
a heat exchanger configured to facilitate heat transfer between a flow of bleed air from the bypass duct of the turbofan engine and the fluid
Implementation Method 2
a fluid propeller configured to drive the bleed air through the heat exchanger, the fluid propeller disposed downstream of the heat exchanger
Data Source
AI summary
Systems and methods for conditioning a fluid using bleed air from a bypass duct of a turbofan engine are disclosed. The system comprises a heat exchanger configured to facilitate heat transfer between a flow of bleed air from the bypass duct of the turbofan engine and the fluid, and a fluid propeller configured to drive the bleed air through the heat exchanger. The fluid propeller is disposed downstream of the heat exchanger.