Browsing by Author "Martin, Peter G."

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    Characteristics of unsteady total pressure distortion for a complex aero-engine intake duct
    (Elsevier, 2018-04-24) Tanguy, Geoffrey; MacManus, David G.; Garnier, Eric; Martin, Peter G.
    Some types of aero-engine intake systems are susceptible to the generation of secondary flows with high levels of total pressure fluctuations. The resulting peak distortion events may exceed the tolerance level of a given engine, leading to handling problems or to compressor surge. Previous work used distortion descriptors for the assessment of intake-engine compatibility to characterise modestly curved intakes where most of the self-generated time-dependent distortion was typically found to be dominated by stochastic events. This work investigates the time-dependent total pressure distortion at the exit of two high off-set diffusing S-duct intakes with the aim of establishing whether this classical approach, or similar, could be applied in these instances. The assessment of joint probability maps for time dependent radial and circumferential distortion metrics demonstrated that local ring-based distortion descriptors are more appropriate to characterise peak events. Extreme Value Theory (EVT) was applied to predict the peak distortion levels that could occur for a test time beyond the experimental data set available. Systematic assessments of model sensitivities to the de-clustering frequency, the number of exceedances and sample time length were used to extend the EVT application to local distortion descriptors and to provide guidelines on its usage.
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    Design of a high-speed intake distortion simulator for propulsion integration research
    (AIAA, 2023-01-19) Migliorini, Matteo; Szymanski, Artur; Zachos, Pavlos K.; MacManus, David; Martin, Peter G.
    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 non-intrusive 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.