Air-Oil Exchanger Support Attachment for Thermal Position Stability
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Solution Overview
Problem
The existing design of air-oil exchanger systems in bypass turbomachines faces challenges due to differential thermal expansions between the inter-flow cowling and the exchanger system, making accurate positioning difficult.
Innovation Solution
The support of the air-oil exchanger system is mechanically linked to the hooking mast via connecting means that cross the inter-flow cowling, reducing the impact of thermal expansions and allowing for adjustable positioning, including a maintenance position for easier access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the support is linked to the engine casing by connecting means arranged in the inter-flow compartment, then the exchanger system can be positioned accurately with respect to the inter-flow cowling, but the differential thermal expansion between the exchanger system and the inter-flow cowling becomes considerable
Solution Approach 1:
The support structure is divided into two distinct linkage systems: connecting means arranged in the inter-flow compartment for positioning, and additional connecting means linking to the hooking mast for thermal stability. This segmentation allows each subsystem to address specific requirements independently.
Solution Approach 2:
The support combines two linkage systems: one to the engine casing and another to the hooking mast. By merging these linkage systems, the support leverages the thermal stability of the hooking mast (which experiences similar thermal conditions) while maintaining positioning capability through the inter-flow compartment connections.
2Object-affected harmful factors
If the support is linked to the hooking mast by connecting means crossing the inter-flow cowling, then the differential thermal expansion is attenuated, but the device complexity increases
Solution Approach 1:
The hooking mast serves multiple functions: it provides structural support for mounting the engine and simultaneously acts as a thermally stable reference structure for positioning the exchanger system. The connecting means to the hooking mast thus serves dual purposes of mechanical support and thermal reference.
Solution Approach 2:
The connecting means arranged in the inter-flow compartment act as intermediaries that transmit positioning requirements from the inter-flow cowling to the support, while the connecting means to the hooking mast provide thermal reference. This intermediary arrangement allows indirect compensation for thermal expansion effects.
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 stabilizes the relative positioning between the exchanger system and the inter-flow cowling, reducing the effects of thermal expansions and facilitating maintenance by allowing the support to be displaced into a maintenance position accessible only after opening the inter-flow cowling.
Implementation Method 1
an air-oil exchanger system, whose function is to cool down the lubrication oil of the rotating elements of the turbomachine with air sampled out of the compartment, into the secondary flow path
Implementation Method 2
the inter-flow cowling and the air-oil exchanger system are subjected to different temperatures which could lead to a considerable differential expansion
Data Source
AI summary
An engine assembly for an aircraft including a bypass turbomachine as well as a turbomachine attachment pylon including an air-oil exchanger system arranged in an inter-ducts compartment between the flow ducts, the compartment being delimited radially on the outside by an inter-ducts cowling, the exchanger system being supplied with air from a secondary flow duct of the turbomachine delimited radially on the inside by the inter-ducts cowling, and the exchanger system being supported by a support arranged in the inter-ducts compartment, this support being mechanically connected to the attachment pylon by connecting means passing through the inter-ducts cowling.