Segmented Hail Screen for Aircraft Engine Air-Oil Cooler
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Solution Overview
Problem
Aircraft air-oil coolers are vulnerable to damage from hailstones due to the fragility of their foils, which can compromise the reliability and availability of the aircraft if not protected.
Innovation Solution
A hail screen is designed with a mesh/grid portion in the line-of-sight of the cooler and a grid-free portion out of sight to minimize flow blockage and protect against hailstones, while being lightweight and easily mountable between the bellows seal and inlet duct, using a flange with bolt holes for attachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hail screen is installed to protect the cooler foils from hailstone damage, then the reliability of the aircraft is improved, but the airflow blockage increases and the cooler efficiency deteriorates
Solution Approach 1:
The hail screen is designed with spatially varying mesh densities - a first portion with a first mesh density in the line-of-sight of the cooler and a second portion with a second mesh density out of the line-of-sight. This local differentiation allows the screen to provide protection where needed while minimizing airflow restriction in critical zones, thus resolving the contradiction between reliability improvement and cooler efficiency maintenance.
2Object-affected harmful factors
If a hail screen with fine mesh is used to protect against hailstones, then the protection effectiveness is improved, but the airflow blockage increases and pressure loss worsens
Solution Approach 1:
The screen implements different mesh densities in different spatial zones - finer mesh in the line-of-sight portion for optimal hailstone protection and coarser mesh in the out-of-line-of-sight portion for reduced pressure loss. This local quality differentiation resolves the contradiction between protection effectiveness and pressure loss.
Solution Approach 2:
The hail screen is segmented into distinct portions with different mesh characteristics - a first portion for protection and a second portion for airflow optimization. This segmentation allows each zone to perform its specific function optimally, balancing protection effectiveness with minimal pressure loss.
3Reliability
If a hail screen is installed between the bellows seal and inlet duct, then the protection of the cooler is improved, but the device complexity and installation difficulty increase
Solution Approach 1:
The hail screen is designed as a segmented component that can be installed between existing components (bellows seal and inlet duct) without requiring major system disassembly. This segmentation approach minimizes installation complexity while providing the necessary protection.
Solution Approach 2:
The hail screen acts as an intermediary component installed between the bellows seal and inlet duct, providing protection without requiring modification of the existing cooler structure or major system changes, thus limiting the increase in device complexity.
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 hail screen effectively protects the air-oil cooler foils from hailstone damage without significantly impacting airflow or surrounding hardware, enhancing the safety and reliability of the cooler system.
Implementation Method 1
An air-oil cooler uses air for purposes of providing a cooling fluid. For example, air is taken from the fan bypass, flowed through the cooler, and returned to the fan bypass as an exhaust.
Data Source
Figure 1
Figure 2
Figure 3A~3C
AI summary
Aspects of the disclosure are directed to a screen (122) configured for use in association with a cooler (106) of an aircraft, the screen (122) comprising: a first portion (332) arranged as a grid and located in a line-of-sight of the cooler (106) with respect to a fluid inlet (102), and a second portion (334) located out of the line-of-sight of the cooler (106) with respect to the fluid inlet (102), wherein the second portion (334) is grid-free.