Non-intrusive flow diagnostics for unsteady inlet flow distortion measurements in novel aircraft architectures

Doll, Ulrich; Migliorini, Matteo; Baikie, Joni; Zachos, Pavlos K.; Röhle, I.; Melnikov, Sergey; Steinbock, Jonas; Dues, Michael; Kapulla, Ralf; MacManus, David G.; Lawson, Nicholas J.

doi:10.1016/j.paerosci.2022.100810

Cited by 22 publications

(13 citation statements)

References 104 publications

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“…In a recent review article [16], an overview on the state-of-the-art in non-intrusive inlet ŕow diagnostics by means of laser-optical particle image velocimetry (PIV) and Doppler global velocimetry (DGV) was provided. When compared to the current industry standard [12], optical measurement methods offer much richer datasets in space and potentially in time by orders of magnitude [17ś19].…”

Section: Fig 1 3d Rendering Of Subsonic Convoluted Diffuser Intake Te...mentioning

confidence: 99%

Seeding-free inlet flow distortion measurement by filtered Rayleigh scattering: diagnostic approach and verification

Doll

Kapulla

Steinbock

et al. 2023

AIAA SCITECH 2023 Forum

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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.

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Section: Fig 1 3d Rendering Of Subsonic Convoluted Diffuser Intake Te...mentioning

confidence: 99%

Seeding-free inlet flow distortion measurement by filtered Rayleigh scattering: diagnostic approach and verification

Doll

Kapulla

Steinbock

et al. 2023

AIAA SCITECH 2023 Forum

Self Cite

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“…The frequency scanning method resolves this problem by introducing further information through the discrete variation of the laser's output frequency, however, this cannot be used to obtain time-resolved flow data. Two recently introduced detection system variants [25] based on the concept of varying perspectives to perform multi-parameter FRS measurements from a single laser pulse are presented in figure 1. The first approach in figure 1, left (Cam.…”

Section: Detection Conceptsmentioning

confidence: 99%

Time-resolved multi-parameter flow diagnostics by filtered Rayleigh scattering: system design through multi-objective optimisation

Doll

Röhle

Dues³

et al. 2022

Meas. Sci. Technol.

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The measurement of the time-resolved three-component (3C) velocity field together with scalar flow quantities such as temperature or pressure by laser-optical diagnostics is a challenging task. Current approaches usually employ combinations of different methods relying on tracer particles or molecules. This typically requires usage of at least two laser systems and detection units as well as elaborate calibration of the luminous properties of the applied tracer species with regard to the specific thermodynamic conditions anticipated for the flow case at hand. In contrast to this, the tracer-free filtered Rayleigh scattering (FRS) technique has been proven to obtain combined time-averaged velocity and scalar fields and might offer a viable alternative for unsteady flow diagnostics. By applying multiple perspective views, two detection system variants are presented, combining 1) six observation branches with one camera/molecular filter and 2) three camera views with two cameras and molecular filters of differing vapour densities. Both configurations in principle allow for the simultaneous measurement of instantaneous 3C velocity, temperature and pressure fields. Multi-objective optimisation is used to enhance the detection setups for different sets of experimental configurations. It is shown that a higher number of observation positions and the associated dynamics of the FRS signal prove to be advantageous compared to the use of less views in combination with two acquisition channels equipped with different molecular filters. It is also shown that the use of circularly polarised laser light offers no advantage over linear polarisation. By demonstrating a moderate sensitivity of the optimised observation arrangement to alignment errors, the presented FRS concept provides a practical solution for the simultaneous measurement of time-resolved 3C flow velocity and scalar fields.

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“…These measurement techniques would also be difficult to apply to full-scale engine tests without previous substantial derisking of the measurement techniques. Such techniques include non-intrusive, optical velocimetry methods such as Particle Image Velocimetry which are already demonstrated in sub-sonic configurations for dynamic distortion measurements (McLelland et al [7], Migliorini et al [8] and Doll et al [9]). In addition, a scaled-down rig configuration would also enable the application of methods that can eventually offer high-resolution, rich datasets to characterise the supersonic intake entry such as dynamic pressure sensitive paint or high-speed shadowgraph techniques.…”

Section: Introductionmentioning

confidence: 99%

Design of a high-speed intake distortion simulator for propulsion integration research

Migliorini

Szymański

Zachos

et al. 2023

AIAA SCITECH 2023 Forum

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High levels of inlet flow distortion can be a critical aspect in supersonic air induction systems due to the complex spatial nature and notable temporal unsteadiness. This can affect the operability and performance of the propulsion system. Simulation of the intake shock system in a relatively less expensive, lower technology readiness level experimental facility can be an important element to mitigate a significant part of the risk that industrial and certification testing carries. The work described in this paper is part of a programme that aims to develop such a distortion simulation test rig where the capability of advanced nonintrusive measurement techniques would be applied in propulsion integration research. The paper describes the concept, preliminary design and sizing of the working section of the rig, the exhaust system design and the integration of the test model. A brief summary of the rig architecture is provided along with details of the high-pressure system that drives the supersonic flow. The work indicates that careful design of the working section is required to ensure sufficient operating range and representative aerodynamics of the test model. It is also shown that the working section wall interference on the test model is tightly linked with the type and size of the aircraft intake to be tested. Ways to mitigate this interference are herein explored. I.Nomenclature ACIntake capture area AH Working section cross-sectional area A0 Area of stream tube entering the inlet Amax Maximum inlet projected area, A* Nozzle throat area Cp Static pressure coefficient H Working section height Ht Intake throat height h Diverter height

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Non-intrusive flow diagnostics for unsteady inlet flow distortion measurements in novel aircraft architectures

Cited by 22 publications

References 104 publications

Seeding-free inlet flow distortion measurement by filtered Rayleigh scattering: diagnostic approach and verification

Seeding-free inlet flow distortion measurement by filtered Rayleigh scattering: diagnostic approach and verification

Time-resolved multi-parameter flow diagnostics by filtered Rayleigh scattering: system design through multi-objective optimisation

Design of a high-speed intake distortion simulator for propulsion integration research

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