Periodic Reporting for period 5 - FAST TAPS (Cooled Fast-Response Wall Pressure Taps for Combustion Chamber Measurements)
Período documentado: 2021-05-05 hasta 2022-08-04
In the framework of the FAST TAPS project, the main objective was the design, manufacturing, and qualification of 8 reliable fast-response large bandwidth wall-static pressure taps for combustion chamber measurements. To achieve this objective, a design methodology had to be developed in order to maximize the frequency bandwidth while still safeguarding the sensor integrity, to protect the fragile sensing element against the harsh combustor environment while still minimizing the probe intrusiveness, and finally, to guarantee a reliable probe performance. Furthermore, an extensive validation and qualification procedure for the prototype and final production probes had to be developed as well.
The FAST TAPS project achievement resulted in the design, manufacturing and full qualification of 8 probes, along with the delivery of a dedicated external cooling system allowing the simultaneous use of 6 probes in the combustor of a ground-based turboshaft gas turbine test rig. The availability of this type of instrumentation would be a fundamental tool to extend the knowledge around combustion instabilities, while directly supporting the development of more performant combustion control systems.
Following a critical review of the proposed probe design, a probe prototype was then produced which was subsequently thoroughly evaluated during the second stage of the project. The structural and mechanical integrity of the prototype was controlled by checking the leakproofness at high internal pressure as well as the pressure losses through the probe with respect to the coolant flow rate. The prototype was then successfully installed in the primary zone of the Safran Tech BEARCAT turboshaft test rig, using Safran Tech's own cooling system as coolant supply source. The probe survived more than 30 minutes at idle engine conditions (where temperature levels in the primary zone already reach beyond 1000 °C), producing valuable and insightful data regarding combustion noise and instabilities. However, a weakness in the sensor packaging meant that soot deposit on the sensor led to a critical sensor failure. As soon as a solution regarding the sensor packaging was adopted, the mass production of 8 probes was successfully achieved during the final stage of the project. The external cooling system, able to provide up to 5 l/min of coolant to 6 probes each simultaneously, was also successfully delivered.
Over the course of the project, the obtained results were actively disseminated by presenting the project outcomes at a Clean Sky 2 workshop on advanced combustor technologies, at 2 symposia on measuring techniques in turbomachinery, as well as at the ASME Turbo Expo 2020 conference. The audience reached through these dissemination activities was mainly academic and industrial in nature. Finally, the exploitation of the knowledge generated within FAST TAPS was also capitalized by means of periodic technical meetings with Safran Helicopter Engines (the Topic Manager), as well as by sharing and discussing comprehensive technical notes and deliverables with the latter.
At first instance, the FAST TAPS project modestly but directly contributed to the achievement of the targets set by the Clean Sky 2 Joint Undertaking program by providing 8 fast-response wall-static pressure probes, allowing a deeper understanding of the combustion instability dynamics and combustion noise generation mechanisms in real engine conditions. Such enhanced knowledge could then be employed in the design of advanced combustion chambers with a significantly reduced NOx production and noise footprint.
In second instance, FAST TAPS paved the way towards the development of air-cooled fast-response pressure probes. The availability of such type of tools would enable in the future (going beyond 2020) their implementation in production engines, providing therefore faster and more precise combustion monitoring capabilities as well as more performant combustion instabilities control strategies. Moreover, the availability of such technology could be considered a business on its own and could contribute to the strengthening of the European competitiveness both on the sensors packaging and monitoring-control markets, sectors still dominated by extra-European actors.