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This Master thesis studies the influence of a splitter vane in a low pressure compressor stator. The analysis is based on CFD simulations conducted in the scope of an internship at Safran Aero Boosters. The goal of this work is to evaluate the aeronautical interest of the technology in the specific study case. More specifically, in a preliminary design phase, it is to determine the relevant geometric parameters and the associated trends. Six parameters are investigated by means of manual geometric iterations.
Booster --- splitter vane --- low pressure compressor --- stall --- stator --- Ingénierie, informatique & technologie > Ingénierie aérospatiale
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The efficiency and onstream time of axial and centrifugal compressors is important for many production units and utility systems. Surge, in particular, can cause system downtime and increase energy use. The flow reversals every few seconds cause severe vibrations that can damage compressor seals and shafts reducing compressor efficiency. And the loss of forward flow often initiates shutdowns of production lines. This book provides a comprehensive view of compressor surge and stall based on first principles and case histories. The process and installation conditions that affect the surge curve and the severity of surge are detailed along with the dynamics of the surge cycle. Solutions are offered to reduce the occurrence and consequences of surge.
Compressors --- Automatic control. --- compressor interaction --- compressor instability --- compressor measurements --- compressor simulation --- compressor speed --- compressor stall --- compressor throttling --- compressor valve --- surge control --- surge curve
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Separated flows are complex but interesting to study because they are variable and unsteady. They are present for every bluff bodies and stalled streamlined bodies (at high angle of attack). Experimental aerodynamics is able to study these types of flow, using pressure sensors. Due to sensor size, pressure tubes are used to connect the pressure scanner to the tap (where the pressure is effectively measured). When an unsteady flow is studied, the signal measured by the sensor is perturbed by the tube. The Transfer Function of the tube has to be computed, to correct for the pressure measure using an inverse Fourier Transform and to obtain the pressure effectively present at the tap. The correction is made on the fluctuation amplitudes (around the mean) and the phase of the signal. The synchronization is important when vortex shedding is studied. This Transfer Function is computed by comparing the pressure measured at the begin and at the end of the tube. For that purpose, pressure with a frequency content has been applied on the tube entry (periodic for KTH calibrator and aperiodic for ULg calibrator). The ratio between these pressures gave the desired correction, showing resonance peaks for some frequencies. When a simple tube is used, theoretical models from fluid equations give very similar results to experimental ones. A parallel with electricity has also been made, replacing the pressure tube by an RLC circuit or a transmission line. The longer and the narrower the tube, the higher the signal distortion. 3D printed models are nowadays commonly used in experimental aerodynamics, allowing not only to build complex shaped models easily, but also pressure taps directly on the model and pressure channels into the structure. These more complex measurement systems have also to be experimentally calibrated. Indeed, diameter restriction on tap or shrinks in tube channels highly distorts the signal. We used this calibration to correct the pressure on a stalled wind turbine wing (at high incidence). The stall is linked to viscous effects, the flow becoming separated and turbulent. The fluctuations and phase of pressure taps signal have been studied to understand the Reynolds effect on a stalled wind turbine wing. Experiments were compared with CFD and theoretical models to validate the results. Another application of unsteady pressure that we have studied the vortex shedding process, occurring around bluff bodies (in particular for rectangular cylinders). The synchronization and amplitude fluctuations of these vortices have been corrected using the dynamic calibration device. Fluid-structure interaction (vortex induced vibration) has then been studied: when vortices were ejected at the resonance frequency of the cylinder, the structure entered auto-excitation and vibrated a lot. When the cylinders were closely spaced in the flow (assembled into a grid), they interfered with each other and the vortex shedding process was changed compared to a single cylinder. To understand deeply this grid, theoretical and numerical models have been used (FEM and CFD) in parallel with experimental sensors: accelerometers (for vibration), pressure sensors connected on taps by tubes, Cobra Probe (velocity in the wake of cylinders), Hot Wire (free stream velocity). The study of this process in function of the incidence and the cylinder spacing allowed us to predict airspeed that induces instability. This is crucial in order to find parameters that minimize vibrations occurring on a real grid, with undesirable noise. In conclusion, this work can be used to take into account unsteady effects when pressure is measured around streamlined and bluff bodies.
Unsteady Flows --- Calibration --- Wind Turbine Wing --- Stall --- Reynolds --- Vortex Induced Vibration --- Rectangular Cylinder --- Grid --- Strouhal --- Fluid-Structure Interaction --- Pressure Measurement --- Wind Tunnel --- Ingénierie, informatique & technologie > Ingénierie aérospatiale
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Sculpture --- proverbs --- Medieval [European] --- iconography --- misericords [choir stall components] --- Iconography --- anno 500-1499 --- Decorative arts [Medieval ] --- Themes, motives --- Congresses --- Art [Medieval ] --- Wood-carving --- Belgium --- Exhibitions --- Proverbs in art --- Misericords --- Choir-stalls
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This book contains state-of-the-art experimental and numerical studies showing the most recent advancements in the field of rotary wing aerodynamics and aeroelasticity, with particular application to the rotorcraft and wind energy research fields.
Technology: general issues --- History of engineering & technology --- rotary-wing aerodynamics --- rotor interaction --- eVTOL aircraft --- computational fluid dynamics --- vortex particle method --- blade design --- wind turbine model --- wind tunnel --- natural laboratory --- vortex detection criterion --- BEM method --- tip vortex interactions --- DAWT --- ducted wind turbine --- H type Darrieus --- VAWT --- dynamic stall --- leading edge vortex --- aeroelasticity --- fluid-structure interaction --- multibody dynamics --- tiltrotor --- handling qualities --- piloted simulation --- wind turbine wake --- helicopter vortex-rotor interaction --- wake vortex encounter --- helicopter offshore operation --- flight safety --- rotorcraft --- offshore wind energy --- rotary-wing aerodynamics --- rotor interaction --- eVTOL aircraft --- computational fluid dynamics --- vortex particle method --- blade design --- wind turbine model --- wind tunnel --- natural laboratory --- vortex detection criterion --- BEM method --- tip vortex interactions --- DAWT --- ducted wind turbine --- H type Darrieus --- VAWT --- dynamic stall --- leading edge vortex --- aeroelasticity --- fluid-structure interaction --- multibody dynamics --- tiltrotor --- handling qualities --- piloted simulation --- wind turbine wake --- helicopter vortex-rotor interaction --- wake vortex encounter --- helicopter offshore operation --- flight safety --- rotorcraft --- offshore wind energy
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Wind turbines are one of the most promising renewable energy technologies, and this motivates fertile research activity about developments in power optimization. This topic covers a wide range of aspects, from the research on aerodynamics and control design to the industrial applications about on-site wind turbine performance control and monitoring. This Special Issue collects seven research papers about several innovative aspects of the multi-faceted topic of wind turbine power optimization technology. The seven research papers deal respectively with the aerodynamic optimization of wind turbine blades through Gurney flaps; optimization of blade design for large offshore wind turbines; control design optimization of large wind turbines through the analysis of the competing objectives of energy yield maximization and fatigue loads minimization; design optimization of a tension leg platform for floating wind turbines; innovative methods for the assessment of wind turbine optimization technologies operating on site; optimization of multiple wake interactions modeling through the introduction of a mixing coefficient in the energy balance method; and optimization of the dynamic stall control of vertical-axis wind turbines through plasma actuators. This Special Issue presents remarkable research activities in the timely subject of wind turbine power optimization technology, covering various aspects. The collection is believed to be beneficial to readers and contribute to the wind power industry.
ANN --- DBD plasma actuation --- aerodynamics --- vertical-axis wind turbine --- PSO algorithm --- variable-speed wind turbine --- wind turbine --- wind energy --- analytical model --- wind farm efficiency --- omega arithmetic method --- wake interaction model --- tower fatigue --- floating offshore wind turbine --- dynamic stall --- nonlinear economic-model predictive control --- hydrodynamic motion response --- active flow control --- control and optimization --- wind farm --- blade optimization --- tension leg platform --- structures --- flow control --- Gurney flap --- time-domain coupled model --- drive-shaft torsion --- mixing coefficient --- modified Morison equation --- wind turbines --- FAST --- turbulence intensity
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This book contains state-of-the-art experimental and numerical studies showing the most recent advancements in the field of rotary wing aerodynamics and aeroelasticity, with particular application to the rotorcraft and wind energy research fields.
rotary-wing aerodynamics --- rotor interaction --- eVTOL aircraft --- computational fluid dynamics --- vortex particle method --- blade design --- wind turbine model --- wind tunnel --- natural laboratory --- vortex detection criterion --- BEM method --- tip vortex interactions --- DAWT --- ducted wind turbine --- H type Darrieus --- VAWT --- dynamic stall --- leading edge vortex --- aeroelasticity --- fluid-structure interaction --- multibody dynamics --- tiltrotor --- handling qualities --- piloted simulation --- wind turbine wake --- helicopter vortex–rotor interaction --- wake vortex encounter --- helicopter offshore operation --- flight safety --- rotorcraft --- offshore wind energy --- n/a --- helicopter vortex-rotor interaction
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This Special Issue book contains selected papers from works presented at the 9th EASN (European Aeronautics Science Network) International Conference on Innovation in Aviation & Space, which was held in Athens, Greece from the 3rd until the 6th of September, 2019. About 450 participants contributed to a high-level scientific gathering, providing some of the latest research results on the topic, as well as some of the latest relevant technological advancements. Eight interesting articles, which cover a wide range of topics including characterization, analysis and design, as well as numerical simulation, are contained in this Special Issue.
Technology: general issues --- History of engineering & technology --- electric propulsion --- aircraft --- CENTRELINE --- DC link voltage level --- analytical model --- design space exploration --- gas-turbine performance --- turboshaft --- axial compressor --- blade --- FEM --- CFD --- erosion --- wear --- stall margin --- compressor surge --- brownout --- aircraft thermal management --- hybrid electric propulsion --- surface heat exchanger --- superhydrophobic --- coating --- anti-icing --- spray-coat --- aeronautical --- gas turbine engine --- performance model --- gas path analysis --- robust estimation --- identification --- regularization --- fuzzy set --- membership function --- CubeSat --- CFRP --- structural integration --- functional integration --- structural battery --- embedded battery --- carbon fibre thermoplastic composite --- PEEK matrix --- woven --- aging --- mechanical testing --- static and fatigue --- STOL aircraft --- propeller --- Pareto sets --- propeller optimization --- n/a
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This book contains state-of-the-art experimental and numerical studies showing the most recent advancements in the field of rotary wing aerodynamics and aeroelasticity, with particular application to the rotorcraft and wind energy research fields.
Technology: general issues --- History of engineering & technology --- rotary-wing aerodynamics --- rotor interaction --- eVTOL aircraft --- computational fluid dynamics --- vortex particle method --- blade design --- wind turbine model --- wind tunnel --- natural laboratory --- vortex detection criterion --- BEM method --- tip vortex interactions --- DAWT --- ducted wind turbine --- H type Darrieus --- VAWT --- dynamic stall --- leading edge vortex --- aeroelasticity --- fluid-structure interaction --- multibody dynamics --- tiltrotor --- handling qualities --- piloted simulation --- wind turbine wake --- helicopter vortex–rotor interaction --- wake vortex encounter --- helicopter offshore operation --- flight safety --- rotorcraft --- offshore wind energy --- n/a --- helicopter vortex-rotor interaction
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