Airfoil 2 is held locked in the most efficient angling position, and the roller is spun at high RPM to produce the most economical ship operation. 9, but would be used in high torque designs in which relatively large rollers, broad airfoils, and slow whirling speeds are used. 8 tends to move toward point c, so that offset i becomes smaller; point e moves rearward, broadening the overall chord, and the upper and lower contours become relatively flatter. But a roller can become so short on the root end of the blade that it cannot sufficiently control the blade for this transition, and is too short for controlling whirling RPM by varying roller speed. With the roller supported by the airfoil in short segments, the use of gearing to speed up the roller RPM permits high values of U/V to be accomplished simultaneously with high whirling tip speeds, both of which are essential simultaneously for high aerodynamic performance.
The functions accomplished are: universal centrifugal blade angle control, varying both r and ψ of expression (5); gyroscopic control of whirling disk coning angle θ (see FIG. The rollers are stiffer, balancing may be more precise, and physical clearances are larger in absolute values, enabling relatively greater aerodynamic refinement to be accomplished on the larger roller/airfoils. Capable of a long productive life, relatively free of maintenance costs. The present end plate 5 can be made much larger, encountering only the relatively small drag due to skin friction, and can be of any planform found by testing to be the most effective. When masses 44 are closest together, blade flattening action is at its greatest, for any given value of ψ and ω. Typically, large wind turbines for electric power generation do not employ stabilizing fins for weathervaning the mill shaft to align with the wind, but use mechanically positive “irreversible” drive systems to perform this function.
Large lift coefficients are needed there; these are provided by the high U/V. As many segments of roller as needed may be used. In the roller blade of this invention, the trailing portion of an airfoil is used to streamline the airflow downstream from the roller, to eliminate the strong wake drag experienced by the roller acting alone at values of U/V less than 4.0. The outboard end of the airfoil, consisting of non-spinning aerodynamic surfaces beyond the outboard tip of the spinning roller, is used to decrease the severe induced drag experienced by the roller acting alone at high lift coefficients. Dolor de espalda despues de un accidente . Pitching moments due to the profile drag of the airfoil section acting at the aerodynamic center are sufficiently small to be neglected.
In the wind ship, the generally horizontal resultant of the wind forces on the blade acts structurally through this joint as a horizontal force, acting from airfoil 2 to blade shank 3B to ship structure 3A, producing movement of the ship, delivering the useful power which propels the ship. It cancels major bending moments at each joint between parts, eliminating the transmission of all major bending stresses across joints.
In such a structure large deflections may occur at the joints, but they are not accompanied by the large stresses which are the fundamental cause of material failure. 2) At higher values of U/V, the size of the turbulent wake decreases, reducing drag from that source, but induced drag, caused by pressure escaping at the free tips, becomes large. Single large diameter high RPM roller. The designer may deliberately increase blade drag at low U/V and seek maximum efficiency at high U/V, so as to make the blade more strongly responsive to a change of roller RPM. The aerodynamic performance of the Magnus roller is dominated by the ratio U/V, where U is the outer surface velocity of the roller section, due to spinning on its axis, and V is the velocity of the approaching wind, perpendicular to the roller axis.
The Flettner windmill had no structure to resist gyroscopic moments, except internally inside the roller itself. But these older spinning end disks produced aerodynamic circulation, so that they did not serve purely as aerodynamic barriers but also generated useless circulation which of itself produced induced drag. Not damaged or rendered inefficient by severe gusts, strong winds, or wind stream dissymmetries. The blade whirls around one or the other of these axes, counterclockwise on the diagram, generating a component of wind velocity at the aerodynamic end (FIG. The horizontal (or vertical) component of the driving force reverses direction twice each revolution, or 6.66 times per second. 17, in the direction of arrow A, allowing airfoil 2 to rotate in pitch, nose down, decreasing its lift coefficient, as far as necessary. 7, shows a typical aerodynamic blade cross section for sailing ship 8. Dolor intenso detras de la rodilla . Trim tab 2A is shown in its neutral position (solid lines) and in a displaced position (dotted lines), in a position to displace airfoil 2 clockwise.
The present invention relates to improvements in wind power machines.
It does not produce enough torque for some applications. This is a pitch change mechanism of unusual simplicity which has the advantage that airfoil 2 is not mechanically restrained in any way in angle of attack so that it is free to weathervane in gusts, thereby avoiding structural damage. On the body downwind from the mass support joint, vertical and horizontal tail surfaces, or their aerodynamic equivalents, are attached to the body so that it points into the wind, even when the wind is not horizontal. The present invention relates to improvements in wind power machines. Only when the ship moves against the resistance of the water or the power shaft turns against a resisting torque is there any production of mechanical power by the wind machine.
Consequently, the wind turbine, in gusty winds, accomplishes reduced structural loading, reduced stresses, and improved efficiency, by means of mechanical articulation throughout, with centrifugal, gyroscopic, and aerodynamic control and stabilization of its components. They employ expensive mechanisms to control their speed and shut them down to protect them from destructive forces, thereby failing to collect energy when it is potentially abundant. Principles of Aero-Centrifugal Control of Blade Angle of Attack In this specification where airfoils, airfoil sections, and blade sections are described, the word “upper” refers to the negative pressure side, and “lower” refers to the positive pressure side, as on an airplane wing, and the drawings are usually positioned that way. This behavior is totally unlike that of a rigidly mounted conventional airfoil section, the lift and drag of which are directly determined by its angle of attack.
- En la diabetes afecta la microcirculación sanguínea
- Dolor que interfiere en la realización de la actividad diaria
- Lugares públicos
- Atletas o deportistas que practican deportes de fuerza o musculación
- Inflamación u otras enfermedades de la pleura (cobertura de los pulmones)
- Compensar los cambios que van ocurriendo
Spring 59 is then compressed axially, to permit removal of one end from its flange hole, and the spring is pre-loaded in torsion around axis p to the design value, in the direction to press pin 64 against the end of the recess in shank 60, in the position shown in FIG. The situation at the end is the same as at the start, except that the whole pattern of geometry–roller, airfoil, streamlines, and the directions of action of all the pressures and forces–has taken up a new alignment rotated by the angular amount Δα, the same as the change of angle of wind direction. This is done by eliminating the pitching restraint of the airfoil, by converting it to a weathervane, pivoting around a forwardly located axis. The blade, whirling around the mill axis and riding freely on weathervaning axis p takes an angle of attack in which the net pitching moments around that axis are balanced and equal to zero.
Dolores Musculares Piernas
In FIG. 1A centrifugal pitching moments (FIG. The details shown in FIG. At the right end of the upper diagram, at view B–B, is the aerodynamic action illustrated in FIG. The Free Weathervaning Pivot and the Aerodynamic Center of the Blade The airfoil blade must weathervane freely if it is to be immune to the effects of gusts.
The body is freely pivoted in yaw and pitch at the top of the support mast. Dolor muscular despues de entrenar . An aircraft responds differently, because it is a free body. For elements of mass lying in quadrants (ii) and (iv) the contributions are “anti-blade-flattening” (negative, counterclockwise). An example of a roller/airfoil section for a somewhat smaller U/V is shown in FIG. FIG. 13, taken at section 13–13 of FIG. See FIG. 1C. Thus, the first balanced pair will produce a nose-up (clockwise, positive) centrifugal moment and the other balanced pair will produce a nose-down (counterclockwise, negative) centrifugal moment; the pairs oppose each other. 10, taken at section 10–10 of FIG. The conventional rigidly mounted whirling blade of a wind turbine operating in this wind encounters a cyclic change of blade section angle of attack every revolution, even in the steadiest winds.
The resultant aerodynamic force at the aerodynamic center consists almost entirely of lift, and lift is proportional to the aerodynamic angle of attack, α, of the section. The angle of attack α approaches the stalling angle, and the aerodynamic drag of the blade increases, interrupting the growth of RPM. Δψ. The rotation of the blade in angle of attack changes ψ by the same amount that α is changed. But, when fast whirling occurs, the pressures across these bearing surfaces decrease, so that relative rotation of shank 60 and spindle 61 is no longer prevented. Another circuit of the same type is used, but with actions reversed, which moves masses 41 apart from each other when RPM becomes too great.