Fluid-Driven Propeller Increases Bleed Air Flow Through Aircraft Pre-Cooler
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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
1Object-affected harmful factors
If pre-cooler size is reduced to decrease pylon size and aerodynamic drag, then aircraft performance is improved, but cooling capacity becomes insufficient under maximum load conditions
Solution Approach 1:
The patent applies a variable geometry inlet guide vane system that dynamically adjusts the bleed air flow angle and rate through the pre-cooler. The inlet guide vanes can rotate to different positions (e.g., 0 degrees for maximum flow, 15-30 degrees for reduced flow) to match varying thermal loads, allowing the pre-cooler to maintain adequate cooling capacity across different operating conditions while using a smaller overall unit size.
Solution Approach 2:
The system changes the flow parameters of bleed air by using adjustable inlet guide vanes to control the flow angle and velocity. By varying the inlet flow angle parameter, the system optimizes heat transfer efficiency at different operating points, enabling a smaller pre-cooler to achieve the required cooling performance that would otherwise require a larger fixed-size unit.
2Weight of stationary object
If pre-cooler size is reduced to decrease pylon size, then aircraft weight and drag are reduced, but bleed air flow rate through the pre-cooler becomes insufficient
Solution Approach 1:
The adjustable inlet guide vanes create a dynamic flow control system that increases bleed air flow rate through the pre-cooler when needed. By rotating the vanes to a more open position, the system maximizes the amount of bleed air directed through the heat exchanger, compensating for the reduced pre-cooler size and maintaining adequate cooling capacity.
Solution Approach 2:
The system modifies the bleed air flow parameters by changing the inlet flow angle and velocity distribution across the pre-cooler face. This parameter adjustment optimizes the heat transfer process and increases the effective bleed air flow rate through the smaller pre-cooler unit, achieving the same cooling effect as a larger pre-cooler with fixed geometry.
3Device complexity
If fixed geometry pre-cooler is used, then device complexity is reduced, but adaptability to varying thermal loads is limited
Solution Approach 1:
The patent introduces a dynamically adjustable inlet guide vane mechanism that allows the pre-cooler to adapt to varying thermal loads. The vanes can be rotated to different angles based on the required cooling capacity, enabling the system to optimize performance across a range of operating conditions while adding only moderate complexity to the overall structure.
Solution Approach 2:
The inlet guide system is segmented into multiple adjustable vane elements that can be independently controlled. This segmentation allows for fine-tuned adjustment of the bleed air flow distribution across the pre-cooler face, providing versatile adaptability to different thermal load conditions while maintaining a relatively simple overall structure.
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 affecting thrust-specific fuel consumption only during non-critical 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-driven fluid propeller configured to drive the bleed air through 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. In one embodiment, such 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-driven fluid propeller configured to drive the bleed air through the heat exchanger.