Placement of additional control devices along the span of the wind turbine blades is being considered for multi-MW wind turbines to actively alter the local aerodynamic characteristics of the blades. This smart rotor approach can reduce loads on the rotor due to wind field non-uniformity, but also, as presented in this paper, can supplement the pitch control system. Rotor speed and tower vibration damping are actively controlled using pitch. By supplementing the speed control using smart rotor control, pitch actuator travel is reduced by 15 pitch rates by 23 and pitch accelerations by 42 This is achieved through filtering the pitch demand such that high frequency signals are dealt with by the smart rotor devices while the low frequency signal is dealt with by pitching the blades. It is also shown that this may be achieved while also using the smart rotor control for load reduction, though with reduced effectiveness. This shows that smart rotor control can be used to trade pitch actuator requirements as well as load reductions with the cost of installing and maintaining the distributed devices
This paper investigates the hydrodynamical aspects of a fixed FPSO in regular waves. The emphasis is geared to the validation of state of the art CFD techniques, using particle image velocimetry measurements on the water velocities around a captive model of an FPSO in regular waves. The main focus is on the following issues: Determination of the water velocities around the vessel using PIV techniques and pressures on a girth below and just above the mean waterline of the vessel using pressure gauges. Comparison of the detailed RANS simulations of the flow around the bilges of the FPSO. The resulting pressure profiles along the girth, especially near the waterline, showed a significant non-linear effect in steep beam wave conditions. The velocities as measured near the bilges of the vessel indicated a strong separation at the bilges of the vessel. This leads to an overestimation of the water velocities near the bilges of the vessel as calculated using a linear diffraction programme. The resulting pressure profiles along the girth, especially near the waterline, showed a significant non-linear effect in steep beam wave conditions. The velocities as measured near the bilges of the vessel indicated a strong separation at the bilges of the vessel. This leads to an overestimation of the water velocities near the bilges of the vessel as calculated using a linear diffraction programme. RANS simulations will give a more realistic flow profile around the bilges.
A Garrett T76 turboprop was used as the test vehicle to evaluate the effects of varying fuel properties on engine hot-section performance and durability. This program was funded by the Naval Air Propulsion Center (NAPC) as part of their program to determine fuel effects on Navy fleet engines. The test fuels were supplied by NAPC and the fuel properties covered a range of values that are being considered for possible future fuel specification modification. Testing was performed on a full-scale combustion rig at conditions duplicating actual engine operation and on a T76 engine. Rig tests were used to determine turbine inlet temperature quality, lean stability, and ground ignition and altitude relight limits. Engine tests evaluated combustor liner temperatures, gaseous emissions, smoke, carbon deposition and fuel thermal stability. Following testing, regression analyses were performed to quantify the effects of specific fuel property values on combustor performance and durability.
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