Aircraft Propulsion Fixed Structure Evacuation Slot
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Solution Overview
Problem
As engine bypass rates increase, the cores and surrounding compartments in aircraft propulsion systems become hotter, necessitating effective heat evacuation to manage temperature and allow for lighter material usage.
Innovation Solution
Incorporating a fixed interior structure with a hot gas evacuation slot that allows fluid communication between the secondary vein and the compartment around the core, featuring a front and rear panel with spacers, and a design that includes an inclined plane and fold to facilitate the evacuation of hot gases, thereby reducing the temperature around the core.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the bypass ratio of engines is increased, then the thrust efficiency is improved, but the temperature of the core and surrounding compartment increases
Solution Approach 1:
The fixed internal structure is divided into front and rear panels with a slot between them, creating a segmented structure that allows hot gas evacuation while maintaining overall structural integrity. This segmentation enables thermal management without compromising the engine's thrust efficiency.
Solution Approach 2:
Hot gases are extracted from the compartment around the core through the slot in the fixed internal structure. This extraction of harmful hot gases reduces the temperature in the compartment, allowing the engine to maintain high bypass ratio for improved thrust efficiency without excessive heat accumulation.
2Temperature
If the temperature around the core is reduced, then lighter materials can be used, but the structural integrity may be compromised
Solution Approach 1:
The fixed internal structure features local quality variations with the front panel having an inner wall and outer wall joined by an inclined plane, and the rear panel having front and rear parts connected by a fold. These local structural variations provide strength where needed while allowing hot gas evacuation slots in less critical areas, maintaining structural integrity while reducing compartment temperature.
Solution Approach 2:
The fixed internal structure combines different structural elements (front panel with inclined plane, rear panel with fold, spacers, and struts) to create a composite structure that provides both thermal management capability and structural strength, enabling the use of lighter materials in the compartment while maintaining overall integrity.
3Temperature
If a slot is added to the fixed internal structure for hot gas evacuation, then the temperature is reduced, but the structural complexity increases
Solution Approach 1:
The slot for hot gas evacuation is merged into the design of the fixed internal structure by utilizing the gap between the front and rear panels. This integration approach allows thermal management functionality to be incorporated without adding separate complex evacuation systems, reducing overall device complexity while still achieving temperature reduction.
Solution Approach 2:
The fixed internal structure serves multiple functions: it provides structural support, defines the compartment volume, and enables hot gas evacuation through the slot. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity while achieving effective temperature control.
4Productivity
If spacers and struts are added to maintain the slot geometry, then the evacuation efficiency is improved, but the manufacturing complexity increases
Solution Approach 1:
The spacers and struts are nested within the overall fixed internal structure, with spacers positioned between the front and rear panels and struts arranged across the slot. This nested arrangement allows the evacuation efficiency to be improved through proper geometric maintenance while keeping the manufacturing process integrated into the existing structure fabrication, rather than requiring separate assembly steps for each component.
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 effectively evacuates hot gases, limiting the temperature around the core and enabling the use of lighter materials by creating a pathway for heat dissipation through the secondary vein, thus addressing the thermal management challenge.
Implementation Method 1
the slot allows fluidic communication between the secondary flow and a compartment which is inside the fixed internal structure and around the core
Implementation Method 2
at a rear end of the front panel, the inner wall joins the outer wall by an inclined plane; the rear panel takes the form of a plate which has a front part extending at a distance from the inner wall, a rear part which is behind the front part and which extends at a distance from the outer wall, and a fold which connects the rear part and the front part
Data Source
Figure 1~7
Figure 2~3
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AI summary
The invention relates to an aircraft propulsion system (150), said propulsion system (150) comprising a core (152), a fixed internal structure (162) integral with and arranged around the core (152), and a nacelle (154) surrounding the core (152) and the fixed internal structure (162), wherein a secondary flow (160) is delimited between the fixed internal structure (162) and the nacelle (154). The fixed internal structure (162) has a slot (164) that allows fluidic communication between a compartment (163) located inside the fixed internal structure (162) and the secondary flow (160). The presence of the slot allows the evacuation of some of the hot gases present in the compartment around the core, thus limiting the temperature of the core and the area surrounding the core.