Compressor Speed Control for Air Separation Module Temperature

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Solution Overview

Problem

Existing on-board inert gas generation systems for aircraft face inefficiencies in maintaining the non-enriched air temperature within the desired operating range, particularly when there is no airflow through the ram air duct, leading to overheating issues that require additional cooling methods like bleed air, which introduces inefficiencies.

Innovation Solution

A controller is implemented to adjust the speed of the compressor system based on temperature and airflow parameters, ensuring the non-enriched air entering the air separation module remains within the desired temperature range by reducing compressor speed when undesired temperatures are detected.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the compressor system operates at high speed to maintain productivity, then the non-enriched air temperature exceeds the desired operating temperature range, but reducing compressor speed maintains temperature control

Engineering Contradiction:
Improvenon-enriched air temperatureVSAvoidinert gas production rate
Core Design Contradiction:
TemperatureVSProductivity

Solution Approach 1:

The compressor system operates at variable speeds rather than a fixed high speed, allowing the system to dynamically adjust compressor rotational speed based on real-time temperature conditions and ram air availability, optimizing both temperature control and productivity

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The controller receives temperature signals from the temperature sensor and continuously adjusts compressor speed based on feedback regarding whether the non-enriched air temperature is within the desired operating range, creating a closed-loop control system

Inventive Principle:
Principle #23Feedback

2Temperature

If bleed air is supplied to the ejector to induce airflow for cooling, then the non-enriched air temperature is controlled, but system efficiency decreases due to additional energy consumption

Engineering Contradiction:
Improvenon-enriched air temperatureVSAvoidenergy efficiency
Core Design Contradiction:
TemperatureVSUse of energy by moving object

Solution Approach 1:

The system uses free ram air flow from aircraft motion to cool the non-enriched air through the heat exchanger, eliminating the need for additional energy-consuming cooling mechanisms like bleed air supply during flight conditions

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The harmful hot non-enriched air is extracted from the system and replaced with cooled air from the heat exchanger using ambient ram air, removing the need for energy-intensive active cooling systems

Inventive Principle:
Principle #2Taking out (Extraction)

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 approach effectively maintains the non-enriched air temperature within the desired range of 175°F - 205°F (79°C - 96°C), enhancing the efficiency of nitrogen enriched air production without introducing additional cooling inefficiencies, thus improving the overall performance of the on-board inert gas generation system.

Implementation Method 1

A heat exchanger is typically arranged in a ram air duct in fluid communication between the compressors and the air separation module to cool the non-enriched air. The non-enriched air is cooled when ram air flows through the heat exchanger

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Implementation Method 2

The compressor system is configured to rotate at a speed and provide the non-enriched air to the air separation module

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP2163476B1On-board inert gas generation system with air separation module temperature control
Publication Date: 2014.04.02 HAMILTON SUNDSTRAND CORP
  • EP2163476B1 patent drawingFigure 1

AI summary

An on-board inert gas generation system is disclosed that includes an air separation module (30) that is configured to produce nitrogen enriched air from a non-enriched air. The non-enriched air to the air separation module has a desired operating temperature range. A compressor system (14) is in fluid communication with the air separation module. The compressor system is configured to rotate at a speed and provide the non-enriched air to the air separation module. A controller (42) is in communication with the compressor system and is configured to reduce the speed in response to a parameter reaching an undesired value, which would result in a non-enriched air temperature that would exceed the desired operating temperature range. The reduced speed is selected to maintain the non-enriched air temperature within the desired operating temperature range.