Inflatable Flexible Hot Air Duct for Aircraft Bilge Cooling
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Solution Overview
Problem
Conventional methods for removing waste heat from heat generating devices in aircraft bilge areas either increase aircraft weight and cost through skin heat exchangers or drag and pressurization management efforts by releasing heat overboard.
Innovation Solution
A flexible, inflatable hot air duct that uses the aircraft structure as a heat sink, allowing for efficient heat exchange and lightweight design by inflating to surround aircraft structures and releasing heat through a porous material for cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a skin heat exchanger is integrated into the primary structure of the aircraft, then waste heat can be effectively cooled, but the weight and cost of the aircraft increase
Solution Approach 1:
The patent employs a flexible bladder made of elastomeric material that can be inflated to contact the aircraft skin, replacing the need for rigid skin heat exchangers. This flexible membrane approach significantly reduces structural weight while maintaining thermal exchange capability between the hot air and aircraft skin
Solution Approach 2:
The system uses pneumatic inflation of the bladder with hot air to create contact pressure against the aircraft skin, enabling thermal exchange without rigid mechanical structures. The pneumatic pressure ensures consistent thermal contact while allowing the lightweight flexible bladder to conform to the skin surface
2Temperature
If waste heat is removed by releasing an air stream overboard through an opening in the aircraft skin, then cooling is achieved, but drag increases and additional pressurisation management efforts are required
Solution Approach 1:
The aircraft skin itself serves as the heat exchanger surface, eliminating the need for separate cooling outlets or overboard venting systems. The hot air is contained within the aircraft envelope, using the skin as a radiative and conductive heat sink, thereby avoiding drag-inducing openings and additional pressurization management
Solution Approach 2:
The aircraft skin performs multiple functions: it serves as both the structural envelope and the heat exchange surface. This multi-functionality eliminates the need for dedicated cooling outlets, reducing drag and simplifying pressurization management while effectively removing waste heat
3Stability of the object's composition
If the body of the hot air duct is made rigid to maintain shape, then structural stability is improved, but weight and complexity increase
Solution Approach 1:
The bladder transitions from a deflated flexible state to an inflated stable state, gaining structural rigidity dynamically when needed. The elastomeric material provides sufficient shape stability when pressurized with hot air, eliminating the need for rigid structural support while maintaining lightweight characteristics
Solution Approach 2:
The physical state of the bladder changes from soft and flexible when deflated to rigid and stable when inflated with hot air. This parameter change in structural stiffness is achieved through pressure injection, providing shape stability only when required for thermal exchange functionality
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 a cost-effective and lightweight method for waste heat removal, enhancing cooling efficiency while minimizing drag and weight, and allowing for adjustable heat exchange based on the aircraft's thermal load.
Implementation Method 1
The body is made of a flexible material and is configured to be inflated if air is received through the inlet
Implementation Method 2
the aircraft structure(s) can be employed as a heat sink, if the heat can pass through the flexible material of the body from the hot air into the aircraft structure(s)
Implementation Method 3
the heat can pass through the flexible material of the body from the hot air into the aircraft structure(s)
Data Source
Figure 1~2
Figure 3~4
Figure 5(a)~6
AI summary
The present disclosure relates to a hot air duct (100) for an aircraft, particularly a bilge area (3) of the aircraft. The hot air duct (100) comprises a body, an inlet in the body and configured to receive hot air. The body is made of a flexible material and is configured to be inflated, if air is received through the inlet. Further disclosed are an aircraft section as well as an aircraft including such hot air duct (100).