Compact Air Bleed System for Aircraft Propulsion
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Solution Overview
Problem
Conventional air bleed systems in aircraft propulsion systems are bulky due to increasing turbojet diameters, limiting space for the system and requiring the turbojet to be positioned close to the wing, which restricts the integration of the air bleed system.
Innovation Solution
A double-flow turbojet propulsion system with a compact air bleed system that includes a movable flap and perforated grid, allowing regulation of air flow through the heat exchanger and reducing bulk by enabling the heat exchanger to be positioned away from the wing, and utilizing a motor-controlled shutter to manage airflow based on temperature requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a conventional air bleed system is used with a bypass turbojet, then the air conditioning system can be supplied with regulated hot air, but the system becomes bulky and requires the turbojet to be positioned close to the wing
Solution Approach 1:
The patent merges the air bleed system components (heat exchanger, valve, motor) directly into the turbojet structure, specifically integrating them into the nacelle. This consolidation eliminates the need for separate bulky components and reduces overall system volume while maintaining temperature regulation functionality.
Solution Approach 2:
The nacelle is designed to serve multiple functions: it houses the turbojet engine, integrates the heat exchanger for air conditioning, and incorporates the control valve and motor mechanisms. This multi-functionality reduces the need for separate dedicated components, thereby reducing overall system bulk.
2Power
If the turbojet diameter increases, then the propulsion system can provide greater thrust, but the space available for the air bleed system is reduced
Solution Approach 1:
The air bleed system components are nested within the turbojet nacelle structure. The heat exchanger is positioned within the nacelle volume, and the control valve and motor are integrated into the same space, allowing the air bleed system to occupy only the available internal volume rather than requiring external space.
Solution Approach 2:
The patent utilizes the vertical and lateral dimensions within the nacelle structure to accommodate air bleed system components. By arranging components in three-dimensional space within the nacelle rather than requiring external lateral space, the system can accommodate larger turbojet diameters while still providing space for air bleed functionality.
3Productivity
If the air bleed system is integrated close to the wing, then the turbojet can be positioned for optimal propulsion, but the accessibility and maintenance of the system becomes difficult
Solution Approach 1:
The air bleed system is segmented into distinct functional modules (heat exchanger, valve, motor) that are independently accessible through the nacelle structure. This modular segmentation allows maintenance personnel to access and service individual components without requiring disassembly of the entire propulsion system.
Solution Approach 2:
The nacelle structure serves as an intermediary that provides access pathways to the air bleed system components. Maintenance personnel can access components through the nacelle without needing to work in the constrained space between the wing and the turbojet, thereby improving ease of repair while maintaining optimal propulsion positioning.
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 reduces the overall bulk of the air bleed system, allowing for more efficient integration with the propulsion system and improved accessibility, while maintaining effective temperature regulation of the air conditioning system.
Implementation Method 1
the air coming from the compression stage 504 passes through a heat exchanger 508 also supplied with cold air taken from the secondary stream 510 of the bypass turbojet. After passing through the heat exchanger 508 and having captured calories in the hot air
Data Source
Figure 1~5
Figure 2~4
AI summary
The invention relates to a propulsion system (120) for an aircraft comprising an air system (206), said propulsion system (120) comprising: - a fairing (112) having a perforated grid (114), - a turbofan engine (110) with a compression stage (202) and a secondary flow (204), and - an air intake system (200) comprising a heat exchanger (208), a hot pipe (250) connected between the compression stage (202) and the air system (206), and passing through the heat exchanger (208), and a cold pipe (252) connected between the secondary flow (204) and the perforated grid (114), and passing through the heat exchanger (208).The air intake system (200) includes a flap (210) arranged at the level of the perforated grille (114) and moved by a motor (212) between an open position in which the flap (210) does not obstruct the holes in the perforated grille (114) and a closed position in which the flap (210) obstructs the holes in the perforated grille (114). Integrating the exhaust and regulation function at the level of the perforated grille (114) saves space, which facilitates the integration of the air intake system (200) into the propulsion system (120).