Aircraft Ventilation Nozzle and Valve Assembly
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Solution Overview
Problem
Conventional aircraft ventilation systems produce a noticeable hissing sound due to the acceleration of air through nozzles, which is unacceptable in quieter aircraft environments, and previous attempts to quiet them have either been insufficient or reduced the effectiveness of air flow.
Innovation Solution
The ventilation system positions the valve upstream of the nozzle, with a conduit fluidly coupling them, and optionally includes a muffler to absorb sound energy, while a pintle in the nozzle accelerates air further upstream to reduce noise emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If air is accelerated through the nozzle to produce high velocity flow, then cooling/warming effectiveness is improved, but audible noise increases
Solution Approach 1:
The ventilation system is divided into separate functional components: the valve assembly and the nozzle assembly are positioned at different locations within the overhead compartment. The valve is spaced apart from the nozzle, with air flow path connecting them. This segmentation allows the noise-generating valve operation to be isolated from the noise-sensitive nozzle discharge area, enabling high velocity flow at the nozzle while keeping the valve away from the passenger compartment noise environment.
Solution Approach 2:
A conduit or air flow path serves as an intermediary element between the valve and the nozzle. This intermediate passage allows the air to be controlled by the valve at one location and then delivered at high velocity through the nozzle at another location. The intermediary conduit enables the decoupling of the valve operation (noise source) from the nozzle discharge (performance point), resolving the contradiction between noise reduction and flow velocity maintenance.
2Device complexity
If the valve is integrated with the nozzle, then device complexity is reduced, but noise from valve operation is transmitted directly to the nozzle exit
Solution Approach 1:
The system separates the valve assembly from the nozzle assembly into distinct components with separate functions. The valve is positioned upstream and spaced apart from the nozzle, with only an air flow path connection between them. This segmentation prevents the direct transmission of valve operation noise to the nozzle exit while maintaining functional integration through the air flow path.
Solution Approach 2:
The valve and nozzle are positioned at different spatial locations within the overhead compartment, utilizing the three-dimensional space available. Rather than integrating them at the same location (zero-dimensional integration), the system uses spatial separation in the overhead compartment volume, allowing functional connection through air flow while physically distancing the noise sources from the discharge point.
3Object-generated harmful factors
If different valve types are used to reduce noise, then audible noise is partially reduced, but volume reduction is insufficient
Solution Approach 1:
The noise-generating valve operation is extracted from the nozzle assembly and positioned at a separate location within the overhead compartment. By taking the valve out of the direct noise path to the passenger compartment and spacing it apart from the nozzle, the system achieves noise reduction not through valve type selection but through spatial extraction of the noise source from the performance critical area.
4Object-generated harmful factors
If air pressure is reduced to lower noise, then audible noise decreases, but air flow speed and cooling/warming effectiveness are greatly reduced
Solution Approach 1:
The system segments the pressure control function (valve) from the velocity generation function (nozzle). The valve can operate at lower pressures to reduce noise, while the nozzle design and positioning maintain high velocity flow for effective cooling/warming. This segmentation allows independent optimization of noise reduction and flow velocity without the trade-off that exists in integrated systems.
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
This configuration significantly reduces the audible noise of the ventilation system while maintaining high-speed air flow, making it suitable for quieter aircraft environments without compromising cooling or heating effectiveness.
Implementation Method 1
an upstream portion of the nozzle has a larger diameter than a downstream portion of the nozzle. Accordingly, as a relatively low speed flow of air enters the nozzle, the area of the passageway through which the flow of air passes begins to constrict. This constriction tightens as the flow of air continues down stream through the nozzle. This constriction causes the flow of air to accelerate as the flow of air moves through the nozzle in order to maintain a constant mass-flow rate.
Implementation Method 2
The ventilation system may include a muffler that is fluidly coupled with the conduit such that the flow of air passes through muffler. The muffler may be configured to absorb sound energy from the flow of air when the flow of air flows through the muffler.
Data Source
AI summary
A ventilation system for ventilating a passenger compartment of an aircraft is disclosed herein. The ventilation system includes, but is not limited to, a nozzle that is adapted to be mounted proximate an interior of the aircraft and that is configured to direct a stream of air into the passenger compartment. The ventilation system further includes a valve that is spaced apart from the nozzle and positioned upstream of the nozzle, the valve configured to control a flow of air to the nozzle. The ventilation system still further includes a conduit that fluidly couples the valve to the nozzle. The conduit is configured to convey the flow of air from the valve to the nozzle.