Aircraft Air Mixing Chamber with Diagonal Pockets for Icing Prevention

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Solution Overview

Problem

Aircraft air conditioning systems face issues with icing due to cold and moisture-saturated air, leading to component freezing, and existing solutions result in complex mixing chamber designs.

Innovation Solution

A mixing device with alternating pockets and diagonal partitions directs fresh air from the air conditioning system into separate discharge lines for the cabin and cockpit, using recirculated cabin air to prevent icing and ensure effective mixing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a mixing device branches off fresh air to supply both the aircraft cabin and the cockpit separately, then the air supply requirements are met, but the structure becomes very complex

Engineering Contradiction:
Improveair supply capabilityVSAvoidmixing chamber structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The mixing device is segmented into multiple pockets (first pockets for cockpit supply, second pockets for cabin supply) with diagonal partition plates in each pocket. This segmentation allows the single mixing device to simultaneously serve multiple discharge locations (cockpit and cabin) through separate discharge lines, achieving versatility while maintaining a relatively simple overall structure.

Inventive Principle:
Principle #1Segmentation

2Reliability

If recirculated air is used to surround and heat the fresh air supply line, then icing is prevented, but the component structure becomes complex

Engineering Contradiction:
Improveicing preventionVSAvoidsupply line structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The first supply line for fresh air is nested within the second supply line for recirculated air. The recirculated air flows in the annular space between the two supply lines, surrounding the cold fresh air. This nested arrangement allows the warmer recirculated air to heat the fresh air and prevent icing of the supply lines and mixing device, while maintaining a compact and simple structure.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Reliability

If multiple pockets with diagonal partitions are used for mixing and directing air flows, then effective mixing and icing prevention are achieved, but the manufacturing complexity increases

Engineering Contradiction:
Improvemixing effectivenessVSAvoidpocket structure fabrication
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

Different pockets are assigned different functions: first pockets contain diagonal partition plates to direct fresh air to the cockpit discharge line, while second pockets have diagonal partition plates that direct a mixture of fresh and recirculated air to the cabin discharge line. This local differentiation of pocket functions enables effective mixing and icing prevention in specific areas without requiring complex structures throughout the entire device.

Inventive Principle:
Principle #3Local quality

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 prevents icing by heating the mixing device with recirculated air and ensures efficient air mixing, allowing for adjustable volume flow and simple design, effectively addressing the complexity and icing issues in aircraft air conditioning systems.

Implementation Method 1

Comparatively warm recirculated air from the aircraft cabin thus surrounds the cold fresh air flowing out of the air conditioning system, so that icing due to heat transfer from the warm air can be prevented.

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

the circulated air from the aircraft cabin flows on the other side of the partition plates and, after a 90° deflection, mixes with the fresh air that has passed through the open pockets

Methodology Applied
Scientific EffectFluid mixing: Turbulence

Data Source

PatentEP1944235B1Mixing device for aircraft air-conditioning system
Publication Date: 2010.08.04 LIEBHERR AEROSPACE LINDENBERG GMBH
  • EP1944235B1 patent drawingFigure 1
  • EP1944235B1 patent drawingFigure 2
  • EP1944235B1 patent drawingFigure 3

AI summary

The device (10) has bags, which are arranged one above the other in a flow cross section. The bags exhibit a free cross section in order to conduct fresh air from a supply conduit for fresh air into a discharge conduit for supplying mixed air into an area of an aircraft. The bags exhibit diagonal separation wall for conducting the fresh air in the discharge conduit for supply of fresh air into another area of the aircraft, and led back air from the former area of the aircraft into the discharge conduit for supply of mixed air in the former area of the aircraft.