Browsing by Author "Dues, Michael"
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Item Open Access Seeding-free inlet flow distortion measurement by filtered Rayleigh scattering: diagnostic approach and verification(AIAA, 2023-01-19) Doll, Ulrich; Kapulla, Ralf; Steinbock, Jonas; Dues, Michael; Migliorini, Matteo; Zachos, Pavlos K.The expected close coupling between engine and fuselage of future aero-engine architectures will lead to highly distorted inflows at the engine face, presenting a major design risk for efficient and reliable engine operation. In particular, the increase in flow unsteadiness is perceived as a significant challenge. In this context, the Cranfield Complex Intake Test Facility (CCITF) is currently being installed at Cranfield University to reproduce the anticipated level of total pressure and swirl distortion arising from novel, closely coupled airframe-engine configurations. To address the expected demand for much more comprehensive flow field data, it is intended to establish the filtered Rayleigh scattering (FRS) technique for non-intrusive testing of aero-engine intake flows. Unlike the previously used particle image velocimetry (PIV) or Doppler global velocimetry (DGV), which are limited to the measurement of a single flow quantity, FRS can be used for the combined planar measurement of velocity and scalar fields without the need to add a flow tracer. In this study, an FRS concept with the ability to simultaneously measure high-accuracy time-averaged and time-resolved three-component velocity, static pressure and temperature fields is verified on a simplified mock-up of the CCITF facility. Time-averaged results show excellent agreement with benchmark laser Doppler anemometry (LDA) velocities, static pressure probe measurements and analytical temperature calculations. Moreover, it is shown that the developed concept can be used to determine multiple flow variables from a single-frequency measurement, opening the path towards time-resolved multi-parameter measurements by FRS.Item Open Access Seeding-free inlet flow distortion measurements using filtered Rayleigh scattering: integration in a complex intake test facility(AIAA, 2024-01-04) Migliorini, Matteo; Zachos, Pavlos K.; MacManus, David G.; Doll, Ulrich; Dues, Michael; Jonas, Steinbock J.; Dues, Fritz; Siswanto, Adi; Melnikov, Sergey M.; Rohle, IngoHighly integrated propulsion systems to achieve fuel savings and reduction of emissions in future aircrafts call for new measurement methods to assess inlet conditions at the engine fan face. Propulsion systems are expected to operate at higher levels of total pressure, total temperature, and swirl distortion due to flow interaction with aerodynamic surfaces and inherent flow distortion within convoluted intakes. Filtered Rayleigh Scattering (FRS) offers capability to assess all these quantities at once, and without the need of seeding particles which cannot be used for in-flight measurements. This paper aims at increasing the technology readiness level of this measurement technique through the application on a lab-scale S-duct diffuser tests and benchmark against Stereo-Particle Image Velocimetry (S-PIV) measurements. Methods to improve the optical integration and mitigate the effect of varying background conditions are hereby explored. Overall, this represents a step forward in the use of FRS as a turnkey solution for the testing and development phase of future propulsion systems.Item Open Access Towards time-resolved multi-property measurements by filtered Rayleigh scattering: diagnostic approach and verification(Springer, 2023-12-11) Doll, Ulrich; Kapulla, Ralf; Dues, Michael; Steinbock, Jonas; Melnikov, Sergey; Röhle, Ingo; Migliorini, Matteo; Zachos, Pavlos K.The use of multiple perspective views is a possible pathway towards the combined measurement of multiple time-resolved flow properties by filtered Rayleigh scattering (FRS). In this study, a six view observation concept is experimentally verified on a aspirated pipe flow. The concept was introduced in our previous work, and it has the ability to simultaneously measure high-accuracy time-averaged and time-resolved three-component velocity, pressure and temperature fields. To simulate time-resolution, multi-view FRS data at a single optimised excitation frequency are selected and processed for multiple flow properties. Time-averaged and quasi-time-resolved FRS results show very good agreement with differential pressure probe measurements and analytical temperature calculations and lie within ±2 m/s of complementary laser Doppler anemometry (LDA) velocity measurements for all operating points. The introduction of a multistage fitting procedure for the time-resolved analysis leads to a significant improvement of the precision by factors of 4 and 3 for temperature and axial velocity and 18 for pressure. Moreover, both processing methods show their capacity to resolve flow structures in a swirling flow configuration. It is demonstrated that the developed multi-view concept can be used to determine multiple flow variables from a singlefrequency measurement, opening the path towards time-resolved multi-parameter measurements by FRS.