Multilayer Heat Shield for Aircraft Engine Pylon Fairing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
New-generation aircraft engines with Ultra High Bypass Ratio (UHBR) produce exhaust gases at higher temperatures, exceeding the thermal resistance of existing metal heat shields, and their shorter longitudinal dimensions result in inadequate noise attenuation by traditional nacelle structures.
Innovation Solution
A multilayer heat shield for the rear engine pylon fairing, comprising an insulating core with a honeycomb structure, an outer perforated skin for acoustic damping, and an internal skin for mechanical strength, which forms a thermal barrier and enhances acoustic wave damping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a monolithic metal heat shield is used, then mechanical strength is ensured, but thermal insulation performance is insufficient for UHBR engine exhaust temperatures
Solution Approach 1:
The heat shield is divided into multiple functional layers: an outer skin exposed to hot gases, an insulating core layer for thermal insulation, and an inner skin for mechanical strength. This segmentation allows each layer to be optimized for its specific function, resolving the contradiction between thermal insulation and structural integrity.
Solution Approach 2:
The heat shield uses a composite structure combining different materials: metallic outer and inner skins for strength and heat resistance, and a ceramic or ceramic-matrix composite insulating core for thermal insulation. This composite approach enables the shield to withstand both high temperatures and mechanical loads simultaneously.
2Object-generated harmful factors
If traditional nacelle structures are used, then manufacturing simplicity is maintained, but noise attenuation is inadequate for shorter longitudinal engine dimensions
Solution Approach 1:
The rear fairing structure is designed to perform multiple functions: aerodynamic flow management, thermal insulation, and acoustic attenuation. The fairing incorporates acoustic treatment materials and structures that dampen noise while maintaining its aerodynamic and thermal protection roles, addressing noise attenuation needs without requiring additional dedicated noise control components.
3Temperature
If the heat shield is made from thick metal plate, then mechanical rigidity is ensured, but heat transmission to protected structures increases
Solution Approach 1:
Different parts of the heat shield have different material properties optimized for their local function: the outer skin uses heat-resistant metal with appropriate thickness for withstanding direct gas exposure, the core uses highly insulating ceramic materials for thermal blocking, and the inner skin uses structurally sound material for mechanical support. This local optimization minimizes heat transmission while maintaining necessary rigidity.
Solution Approach 2:
The insulating core layer acts as an intermediary between the hot outer skin and the cooler inner skin, blocking heat transmission while allowing the structural skin to maintain its mechanical rigidity. This intermediary layer decouples the thermal and structural requirements, allowing each to be optimized independently.
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 multilayer heat shield provides improved thermal insulation and noise attenuation, effectively managing higher exhaust gas temperatures and reducing noise pollution, while maintaining mechanical integrity.
Implementation Method 1
an insulating core (34) configured both to constitute a thermal barrier
Implementation Method 2
an outer skin (36) configured to guide the aerodynamic flow and participate in acoustic damping
Implementation Method 3
exhaust gases at higher temperatures, exceeding the thermal resistance of existing metal heat shields
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a rear engine mast fairing, referred to as an APF, comprising, on the one hand, a frame including side panels (26) and transverse reinforcing ribs (24), and on the other hand, a heat shield (28) connected to the frame. The heat shield (28) has a multilayer structure comprising an insulating core (34) configured both to constitute a thermal barrier and to dampen acoustic waves, an outer skin (36) configured to guide an aerodynamic flow and contribute to acoustic damping, and an inner skin (38) configured to ensure the mechanical strength of the shield.The multi-layered structure of the shield allows, on the one hand, the rear fairing of the engine mast to contribute to the attenuation of engine noise, and on the other hand, to improve the thermal insulation provided by the shield by allowing the use, for the insulating core of the shield, of materials having better thermal resistance but low mechanical rigidity, the mechanical strength being essentially ensured by the inner skin of the multi-layered structure.