Variable Turbine Nozzle Control for Single-Pack Cabin Cooling
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Solution Overview
Problem
Aircraft environmental control systems often require dual air conditioning packs to maintain cabin conditions, which is inefficient and unnecessary in certain situations, such as when the plane is on the tarmac, where operating a single pack could suffice.
Innovation Solution
An air cycle machine with a turbine wheel, turbine inlet nozzle, and a poppet member that can be selectively positioned to vary the size of the nozzle, allowing for optimized airflow and reduced power consumption by controlling the pressure within the system to operate with a single pack.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dual air conditioning packs are operated to maintain cabin conditions, then cabin pressurization and cooling requirements are met, but power consumption increases and system efficiency decreases
Solution Approach 1:
The patent applies a variable turbine nozzle with a movable poppet member that can dynamically adjust the nozzle opening size based on operational requirements. This dynamic adjustment allows the single air conditioning pack to vary its airflow capacity, enabling it to meet cabin demands without requiring dual packs, thus reducing power consumption while maintaining reliability
Solution Approach 2:
The invention changes the operational parameters of the single air conditioning pack by using a variable turbine nozzle to adjust airflow quantity. By varying the nozzle opening size through poppet member positioning, the system can match the performance of dual packs with a single pack, optimizing power consumption based on actual cabin requirements
2Reliability
If dual air conditioning packs are used, then cabin conditions are maintained under all conditions, but system complexity and unnecessary operation occur during low-demand situations
Solution Approach 1:
The variable turbine nozzle with movable poppet member provides dynamic control over airflow, allowing the single air conditioning pack to adapt to different operational scenarios. This dynamic capability eliminates the need for dual packs during low-demand situations (such as when the plane is on the tarmac), reducing system complexity while maintaining the ability to meet cabin requirements when needed
3Ease of manufacture
If the turbine nozzle size is fixed, then manufacturing is simpler, but airflow optimization and power consumption efficiency are reduced
Solution Approach 1:
The patent introduces a movable poppet member within the turbine nozzle that can be positioned to vary the effective nozzle opening size. This dynamic configuration allows optimization of airflow and power consumption efficiency during operation, while the basic nozzle structure remains relatively simple for manufacturing. The poppet member mechanism provides the necessary variability without significantly complicating the overall manufacturing process
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 reduces power consumption by enabling the air cycle machine to efficiently condition the cabin air using a single air conditioning pack, improving system efficiency and reducing energy usage.
Implementation Method 1
The valve body controls a pressure on the poppet member to move the poppet member relative to the turbine inlet nozzle
Implementation Method 2
In the turbine(s), the air is expanded to both extract energy from the compressed air so as to drive the shaft (and the compressor(s) coupled thereto) and cool the air for use in the cabin as conditioned cooling air
Data Source
AI summary
An air cycle machine includes a turbine wheel, a turbine inlet nozzle, a valve body, and a poppet member. The turbine wheel is mounted to rotate within the air cycle machine and the turbine inlet nozzle is positioned to direct airflow thereto. The poppet member selectively extends into the turbine inlet nozzle and the valve body controls a pressure on the poppet member to move the poppet member relative to the turbine inlet nozzle to vary the size of the turbine nozzle directing airflow to the turbine wheel.