Variable Section Gas Mixing Pump for Aircraft Cabin Heating
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Solution Overview
Problem
Existing gas mixing systems for aircraft cabin heating struggle to maintain a wide temperature range without causing defusing, particularly when heating needs vary significantly, such as from low outdoor temperatures to moderate temperatures, due to limitations in pressure and flow rate management.
Innovation Solution
A mixing horn with a variable-section injection system, featuring a cylindrical enclosure within the fresh air duct and a shutter mechanism that adjusts the passage section through multiple openings, allowing high-pressure hot air to maintain sufficient injection speed and entrain fresh air effectively, while preventing defusing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a control valve restricts the flow of hot air to vary the temperature of outlet air, then the outlet air temperature can be adjusted, but the hot air pressure at the injector decreases causing the system to lose prime and potentially overheat
Solution Approach 1:
The patent applies the dynamics principle by making the injection cross-section variable through a movable shutter (12) that can be adjusted according to operating conditions. This dynamic adjustment allows the system to maintain optimal injection velocity and pressure across different temperature requirements, preventing loss of prime while achieving the desired outlet temperature. The shutter position can be modified based on the required temperature range, ensuring reliable operation whether heating needs are high or moderate.
Solution Approach 2:
The patent implements parameter changes by varying the physical state of the injection system - specifically changing the cross-sectional area of the injection openings from fixed to variable. By adjusting the shutter position, the effective injection area changes, which modifies the injection velocity and pressure characteristics. This parameter adjustment allows the system to maintain proper priming conditions across a wide temperature operating range without sacrificing reliability.
2Temperature
If the injection cross-section is reduced to control hot air flow, then outlet temperature can be regulated, but the injection velocity decreases causing fresh air entrainment to fail
Solution Approach 1:
The system uses a movable shutter (12) that dynamically adjusts the injection cross-section based on operating requirements. This dynamic control allows the system to maintain sufficient injection velocity even when the overall injection area is reduced, by optimally distributing the flow through multiple openings. The shutter can be positioned to maintain critical velocity thresholds necessary for fresh air entrainment while still achieving the desired temperature reduction at the outlet.
Solution Approach 2:
The patent applies segmentation by dividing the injection system into multiple separate openings (30) in the chamber wall instead of a single large opening. This segmentation allows the hot air to be injected through multiple smaller streams, each maintaining sufficient velocity for effective fresh air entrainment. The movable shutter can selectively close or open individual openings, ensuring that enough active openings remain to maintain proper injection velocity and mixing performance.
3Device complexity
If a fixed cross-section injector is used, then the system structure is simple, but the temperature operating range is limited and defusing occurs when heating needs vary
Solution Approach 1:
The patent transforms the fixed cross-section injector into a dynamic system with a movable shutter (12) that can adjust the effective injection area. This adds some complexity but enables the system to adapt to varying heating demands across a wide temperature operating range. The shutter mechanism allows the injector to maintain optimal performance whether the heating requirement is high (cold outdoor conditions) or moderate (milder conditions), preventing defusing issues that occur with fixed geometry injectors.
Solution Approach 2:
The injection system achieves multi-functionality through the movable shutter (12) that can position itself to create different effective cross-sections. This single device structure serves multiple functions: it can fully open for maximum heating capacity, partially open for moderate heating needs, and maintain proper priming conditions across all operating points. The universal design eliminates the need for multiple fixed injectors for different temperature ranges, reducing overall system complexity while improving adaptability.
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 system achieves a wide temperature operating range with efficient mixing and regulation, preventing defusing issues and ensuring reliable operation across varying heating demands, while being compact, lightweight, and cost-effective.
Implementation Method 1
the hot air is at a relatively high pressure, it carries fresh air with it when injected into the fresh air duct and mixes with this fresh air
Implementation Method 2
the hot air is at a relatively high pressure, it carries fresh air with it when injected into the fresh air duct
Data Source
Figure 1~2
Figure 3~4
Figure 5A~5E
AI summary
A mixing pump (2) according to the invention comprises : a so-called cool air duct; a so-called hot air intake (10) leading into the cool air duct; as well as means for injecting air from the hot air intake (10) into the cool air duct. The hot air intake (10) leads into a chamber (16) arranged at least partially in the cool air duct. The injection means have at least one opening (30), for connecting the inside of the chamber (16) to the inside of the cool air duct, and means (12) for modifying the flow area through the opening to at least one, connecting the inside of the chamber (16) to the inside of the cool air duct.