Overview
Towards the Advisory Council for Aeronautical Research in Europe (ACARE) goals, which intended to reduce aircraft CO2 emissions and fuel consumption by 50 % within the next decade, the Clean Sky program focused its intervention in several concurrent developments, such as aircraft aerodynamics and weight, and highly efficient engine concepts. In this framework, Snecma led the Clean Sky SAGE2 activities, to study the development of an innovative concept based in a geared open rotor engine that will end up as a breakthrough for the next 15 years, thanks to the improvements in the propulsive efficiency, without the penalties of any duct drag.
Along with several engine subsystems and technologies that are being developed in the scope of SAGE2, conducted by several Clean Sky ITD leaders, Avio Propulsione Aerospaziale is responsible for the power gearbox, which was the focus of this bidding activity.
As an innovative high efficiency power gearbox was being developed, it is very important to keep track of as many early physical parameters as possible, in order to provide useful feedback data for design processes optimisation; during operation, similar parameters will allow the aircraft to identify potential structural health problems, such as unexpected vibration, temperature and pressure variations, and metal debris in the oil. In this RTMGear activity, Active Space Technologies (AST) intended to develop a telemetric system based, as much as possible, in proved technologies, while Instituto de Telecomunicações (IT) focused their research in innovative Surface Acoustic Wave (SAW) technologies for measuring temperature and strain in rotating parts.
Funding
Results
Executive Summary:
Towards the Advisory Council for Aeronautical Research in Europe (ACARE) goals, which intended to reduce aircraft CO2 emissions and fuel consumption by 50% within the next decade, the Clean Sky program had focused its intervention in several concurrent developments, such as aircraft aerodynamics and weight, and highly efficient engine concepts. In this framework, Snecma led the Clean Sky SAGE2 activities, to study the development of an innovative concept based in a geared open rotor engine that will end up as a breakthrough for the next 15 years, thanks to the improvements in the propulsive efficiency, without the penalties of any duct drag.
As an innovative high efficiency power gearbox was being developed by the Topic Manager, it is very important to keep the an early tracking of as many physical parameters as possible, in order to provide useful feedback data for design processes optimization; during operation, similar parameters will allow the aircraft to identify potential structural health problems, such as unexpected vibration, temperature and pressure variations, and metal debris in the oil.
Long term RTMGear' consortium developments aimed at providing such capability for real-time continuous in situ monitoring of critical parameters for evaluating the health of critical components, such as shafts, gear teeth, structural components, and bearings. Although the current low TRL RTMGear activity was focused in lab applications, where monitoring physical parameters directly in rotating elements, and in harsh environments, were not possible with currently COTS technology.
The goal of this activity was to develop a telemetric system, composed by three independent Rotating Telemetry Units (RTU), to monitor the rotating elements of the gearbox. A Ring Gear Telemetry Unit (RGTU) and a Sun Gear Telemetry Unit (SGTU), both based on traditional temperature and strain sensors, and respective electronics circuits. A third, Surface Acoustic Wave Sensing Unit (SSU), exploring SAW passive sensors.
In the scope of RTMGear activity, the consortium developed/studied two different telemetry concepts, embracing several technical challenges requested by the Topic Manager, such as:
- Modularity: capability to adapt to different arrangements of strain and temperature channels, and to be applied in different components of the power gearbox, such as sun shaft, sun gears, and ring gear;
- Reduced dimensions: allowing for integration inside power gearbox;
- High speed sensor signals: acquire multiple strain gages with bandwidth in the order of 60 kHz;
- Resist to harsh environment:
> Rotating speed (up to 10,000 rpm);
> High temperature (up to 200 ºC);
> Oil mist.
The RTMGear project was developed in two parallel branches, exploring different approaches to the same problem. A completly new development of an innovative concept for a telemetric system, consisting in new designs for electronics, firmware and software, mechanical, and structural simulation, capable of satisfying the needs of both Ring Gear Telemetry Unit (RGTU) and a Sun Gear Telemetry Unit (SGTU). And, a parallel study on a Surface Acoustic Wave Sensing Unit (SSU) solution was carried out, selecting the best available SAW technologies and testing them applied to the power gearbox scenario.