Blade pitch

About: Blade pitch is a research topic. Over the lifetime, 5321 publications have been published within this topic receiving 63134 citations.

Supercavitating propeller with air ventilation

Abstract: 1. A method of decreasing the deleterious effects of cavitation on a ship propeller comprising providing a propeller having supercavitating blade sections, rotating said propeller to drive said ship, and ejecting air from the suction side of each said blade when said ship speed and propeller speed reach a predetermined point to thereby produce a cavity which extends from the leading edge to a point in the water beyond the trailing edge of said blade and envelops the entire suction side of said blade.

Individual Blade Pitch Control of a Floating Offshore Wind Turbine on a Tension Leg Platform

Abstract: A disturbance accommodating controller (DAC) to reject wind speed perturbations is applied on a 5MW wind turbine mounted on a tension leg platform (TLP). Multi-blade coordinate (MBC) transformation is used to address the periodicity of the floating wind turbine system. A method to apply DAC after applying MBC transformation is developed and several implementation options are presented. Simulations were carried out to assess the fatigue loads of the system in accordance with IEC61400-3 standard design load case 1.2; however simulations were restricted to region 3 analysis due to the lack of region transition logic currently implemented for the DAC. A gain scheduled PI (GSPI) controller is used as a baseline/reference controller to compare the performance of the DAC. Simulation results show that the DAC significantly improves power and speed regulation, reduces tower fatigue loads, and maintains the fatigue loads of the blades and the shaft to a comparable level to the baseline controller applied on the TLP. This improvement is due to the use of individual blade pitching and rejecting wind speed variations. Relative to an onshore wind turbine with a GSPI controller, the DAC reduces tower side-side fatigue load and maintains the blade and shaft loads to a comparable level. Tower fore aft fatigue loads remain higher by 27% (instead of 45% increase by the baseline controller on the TLP).

Propeller pitch control

Abstract: The invention concerns a system for controlling an aircraft propeller. A hydraulic motor controls pitch of the propeller blades. The propeller blades are characterized by the absence of feather-inducing counterweights. An overspeed governor senses when propeller speed exceeds a limit, and, in response, assumes control of the hydraulic motor and drives the blades toward a coarsened pitch position, which reduces the propeller speed. In another form of the invention, a mechanical brake can override the hydraulic motor and mechanically retard a rotating gear, which causes the propeller blades to move toward a coarsened pitch.

Rotor Blade Assembly

Abstract: A rotor blade assembly is disclosed. The rotor blade assembly includes a main rotor blade, the main rotor blade including a pressure side and a suction side extending between a leading edge and a trailing edge, and an auxiliary rotor blade associated with the main rotor blade, the auxiliary rotor blade including a pressure side and a suction side extending between a leading edge and a trailing edge. The rotor blade assembly further includes a support member connecting the auxiliary rotor blade to the main rotor blade. The auxiliary rotor blade is configured to modify a lift force associated with the rotor blade assembly.

Propeller blade pitch control system

Abstract: A propeller blade pitch control system includes a propeller hub for mounting at least one propeller blade, and a propeller shaft which rotates about an axis to rotationally drive the propeller hub. A pitch change yoke located within the propeller hub is configured to change a pitch of the at least one propeller blade in response to hydraulic fluid flow to a pitch change actuator. A propeller gearbox includes a first, rear end and a second, forward end located between the first, rear end and the pitch change yoke, and is configured to apply torque to the propeller hub. A hydraulic transfer bearing located between the first, rear end and the second, forward end of the propeller gearbox is operable to selectively permit a flow of hydraulic fluid from at least one hydraulic flow controller to the pitch change actuator.