Exhaust Casing Arm Sheath for Wire Harness Heat and Vibration
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Solution Overview
Problem
Existing technologies fail to effectively cool and stabilize wire harnesses in the severe thermal and vibrational environment of turbomachine exhaust casings, particularly in unducted single fan engines, while maintaining a small footprint and avoiding interference with the primary gas stream.
Innovation Solution
The exhaust casing incorporates sheaths with shims to hold wire harnesses at a distance from the internal face, featuring ventilation systems and thermal insulation, allowing for cooling and vibration control, and includes movable sheaths to accommodate thermal dilations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wire harnesses are routed through exhaust casing arms, then electrical connectivity is achieved, but thermal damage and vibration wear occur
Solution Approach 1:
A sheath is introduced as an intermediary component between the wire harness and the exhaust casing arm environment. The sheath provides thermal insulation and mechanical protection, isolating the wire harness from direct exposure to high temperatures and vibrations while maintaining electrical connectivity functionality.
Solution Approach 2:
The protection system is segmented into multiple functional components: the sheath for thermal insulation, the shim for positioning and vibration isolation, and the ventilation system for active cooling. This segmentation allows each component to address specific harmful factors independently, improving overall protection effectiveness.
2Object-affected harmful factors
If cooling ventilation is added to protect wire harnesses, then thermal protection is improved, but device complexity increases
Solution Approach 1:
The sheath serves multiple functions simultaneously: it provides thermal insulation, structural support for the wire harness, mounting surface for the ventilation system, and vibration isolation through the shim. This multi-functionality reduces the need for additional separate components, thereby limiting complexity increase.
Solution Approach 2:
The ventilation system utilizes the existing gas flow through the exhaust casing to provide cooling, rather than requiring an independent active cooling system. The sheath structure itself facilitates this self-cooling by incorporating ventilation passages that align with the natural flow direction, reducing system complexity.
3Stability of the object's composition
If sheath is fixed rigidly to accommodate wire harnesses, then positioning stability is improved, but thermal dilation damage occurs
Solution Approach 1:
The sheath is designed with dynamic characteristics that allow it to adapt to thermal conditions. The sheath can expand and contract with temperature changes while maintaining its protective function, and the shim provides adjustable positioning that accommodates thermal dilation without compromising wire harness stability.
4Volume of moving object
If sheath is placed close to arm wall to minimize space, then footprint is reduced, but thermal protection effectiveness decreases
Solution Approach 1:
The sheath is designed as a thin-walled structure that provides effective thermal insulation despite its compact dimensions. The sheath material and geometry are optimized to maximize thermal protection while minimizing the space occupied, allowing close placement to the arm wall without compromising protection effectiveness.
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 solution provides effective thermal and vibrational protection for wire harnesses, maintaining operational integrity and reducing wear, while minimizing space usage and interference with the gas stream.
Implementation Method 1
cooling and vibration control... ventilation systems and thermal insulation
Implementation Method 2
ventilation systems and thermal insulation
Implementation Method 3
movable sheaths to accommodate thermal dilations
Data Source
AI summary
A casing for a turbomachine includes an internal hub, an external flange coaxial with the internal hub, arms extending radially from the internal hub to the external flange, each arm having a wall, two or more wire harnesses that connect a first electrical apparatus, which is arranged radially outside the external flange, and a second electrical apparatus, which is arranged radially inside the internal hub, a sheath extending within an arm at a distance from the wall of the arm, the sheath including an internal face defining an internal cavity that receives the two or more wire harnesses, and one or more shims mounted in the sheath and holding the wire harnesses at a distance from an internal face of the sheath and holding the wire harnesses at a distance from one another within the sheath.