One of the most difficult challenges when planning experiments is to ensure that the phenomena to be measured are not altered by the measurement method itself. Air flows in engine intakes are currently assessed using invasive test methods. Alternative, non-invasive methods require the introduction of particles so that flow distortions can be observed – and these particles can interfere with engine operation. The EU-funded SINATRA project is developing an innovative, laser-based, non-intrusive, seed-free method that does not involve the introduction of media for flow visualization. The aim is to test the turbulence of inlet flows with high spatial and temporal resolution so that next-generation aircraft designs can be tested optimally and accurately.
For future novel close-coupled aircraft engine architectures with BLI concepts, the low spatial and temporal resolution of current test methods makes it difficult to accurately assess inlet flow distortions affecting engine stability with current test technology.
New concepts require the support of numerical means, ground facilities and in-flight testing.
Non-intrusive, laser-based solutions such as PIV or DGV require inlet flow impingement, which comes with a number of caveats, including the requirement for uniform distribution of impingement across the measurement plane and the installation of impingement rakes in the intake subsystem. This is particularly challenging when measuring from the air.
One promising laser-based measurement technique is coreless Filtered Rayleigh Scattering (FRS), which would be ideal for airborne measurements. Due to its potential to provide similar spatial and temporal resolution to other laser methods, it allows even highly dynamic flow distortions caused by the geometry of the complex inlets to be clearly understood.
What is the goal of SINATRA?
Together with Cranfield University, Berliner Hochschule für Technik, Paul Scherrer Institut and the ILA R&D GmbH the SINATRA project plans to further mature the FRS technology and provide the necessary outlook by achieving the following goals: a) Development and validation of a prototype FRS measurement system with a CW laser for time-averaged distortion measurements up to TRL4. b) Upgrade the above prototype to demonstrate an FRS measurement system using a pulsed laser to show the capability of the technology to measure instantaneous distortions in a unsteady flow up to TRL3, c) Provide a ground test facility for inlet distortion measurement available to the entire European aerospace, industrial and scientific community, industrial and scientific community, allowing a wide range of non-intrusive flow measurements representative of future architectures to be investigated simultaneously, and d) using the distortion data from the FRS measurements to characterize the distorted flows relevant to advanced propulsion systems using distortion descriptors.
You can view our latest Publications on Filtered Rayleigh Scattering here.
