Overview
AEC identified specific technologies (eddy current and ultrasonic acoustic sensors, and piezoelectric actuators) as having significant potential for new forms of implementation in engine controls. AEC extended this process of engagement with specialists to ensure state of the art technology is available for aerospace controls.
Specifically within this programme:
- AEC developed new means of interaction between the metering system and the sensors and actuators.
- Micro-Epsilon Messtechnik, a German SME, developed an eddy current sensor system for continuous monitoring and proximity sensing.
- Oxford Radio Frequency Sensors, an SME closely linked to Oxford University Clarendon Laboratory, developed piezoelectric acoustic mass flow measurement developed from recent advances in medical physics.
- AEC pulled through work already committed with Newcastle University to develop piezoelectric acoustic position sensing, also drawing on research work underway with Leeds University. Some of this design and manufacturing work will probably be sub-contracted to a Danish specialist company, Noliac
- AEC also pulled through work already underway with Bath University to develop a new generation of piezoelectric actuators with the potential to actuate both direct drive and servo-system control of aerospace fuel systems.
- AEC carried out whole system environmental testing on in house test facilities normally used for the development and qualification of civil and military fuel control systems for production application.
All these systems were compact, robust, reliable, and precise by virtue of the base technologies that are being applied, and also due to the design capability within AEC to design fit for purpose aerospace controls.
Funding
Results
Executive Summary:
Aero Engine Controls (AEC) identified several new technologies that offer the potential to provide the benefits to next generation fuel systems sensors and effectors.
This programme planned to develop these technologies independently of each other with Partners within the Consortium, specifically;
Acoustic Sensor (AEC)
AEC worked with both Morgan and Newcastle to carry out analysis and testing to confirm the proof of concept of the units both in the laboratory and on an AEC test rig (referred to as the first generation sensor). Testing of the first generation sensor design identified issues with the method of mechanical attachment of the active sensor element (the piezo-ceramic), as such a second generation sensor was designed by AEC, with the need to optimise the sensor packaging to make the sensor more compact and able to be fitted in a variety of different engine control applications. Unfortunately, testing proved that the second generation sensor was still not successful and as such further test programmes were put on hold and would be evaluated at a later date.
Piezoelectric Sensor (AEC)
A significant part of this activity was sub-contracted to the University of Bath. Five concepts were developed and the parties agreed that the Noliac ringbender was the suitable option. Laboratory demonstrator tests were completed and further investigation was required to look at suitable clamping options.
During 2014 the prototype still had several issues that needed fixing and the temperature testing was planned but not completed by June 2014.
Mass Flow Sensor (Oxford RF)
Oxford RF Sensors were selected to develop a fuel mass flow measurement system using high frequency ultrasonic techniques. Initial tests at Oxford RF showed that the sensor had potential for further development; however, after further testing of the mass flow measurement technology, it was considered that the project required substantial further development before it was appropriate to progress and as such the project was put on hold.
Eddy Current Sensor (Micro Epsilon)
The Eddy Current sensor was proposed as a replacement for Linear Variable Differential Transformers (“LVDTs”) used in current Fuel Metering Units. Eddy current sensors can offer significant size, weight, measurement accuracy, speed and reliability benefits compared to current LVDT technology. Micro Epsilon delivered 2 off sensors to AEC for testing. The intent was to complete the environmental test as a block test but it was decided that this was not be worthwhile above the components test and the testing was not progressed further.
The technologies are being considered for possible applications on the next engine platforms and / or further technology development programmes, for example, piezo devices are being considered for a servo valve replacement as part of a UK specific funded activity.