The rotors shown in the Figures are similar to the rotors 3 0 illustrated in Figures 1, 2 and 3 herein1 but it will be appreciated that the two-stage rotor apparatus could comprise any pair of rotors with the required helical blade shape, such as any of the alternative embodiments and variations of rotors described herein. In a particularly preferred embodiment, a first rotor as described above is provided in combination with a second rotor as described above, with the large diameter ends of the first and second rotors opposing one another, such that fluid exits the large diameter end of one rotor and then enters the large diameter end of the other rotor. Viewed from a second aspect, the invention provides a method comprising use of a rotor as described above for the production of rotational kinetic energy from flow of a fluid. The shape and form of the rotor may be selected as discussed above in relation to the method of the third aspect.
- Infecciones o enfermedades cutáneas
- Debilidad simétrica relativa
- Etiopatogenia. Tipos de dolor oncológico
- Cuando se sienta demasiado fácil, sujeta mancuernas en las manos como desafío adicional
- Debilidad muscular
- Postura del niño o balasana
- Aceite esencial de eucalipto
The blades 2 extend between the inner peripheral surface 3 and the outer rim 1 and hence form enclosed flow paths. Other variables that have a direct effect on the power extracted are the initial and final radii of the pair of conic helixes (and thus the minimum and maximum inner and outer diameters of the rotor) and the overall length of the rotor. The housing may enclose the rotor and support bearings or shafts enabling rotation of the rotor. Viewed from a sixth aspect, the invention provides a method of manufacturing a two-stage rotor apparatus comprising: mounting a first rotor for rotation about an axis of rotation, the first rotor having at least one helical blade with a pitch that decreases in a direction along the axis of rotation; and mounting a second rotor for rotation about the same axis of rotation in an opposite direction of rotation, the second rotor having at least one helical blade with a pitch that increases in the same direction along the axis of rotation.
Fisioterapia A Domicilio
In the rotors described herein a solid surface bounding the body of flowing fluid is formed by the front and rear of a pair of rotor blades and the inner and outer rims of the rotor. The rotor blades 2 extend between the inner peripheral surface 3 and the outer rim 1 and are fixed to either the inner peripheral surface 3 or the outer rim 1 for rotation therewith. Since the two-stage rotor apparatus is capable of efficient operation with flow in either direction it is not necessary to provide a mechanism for rotation of the tower when the tidal flow changes direction, An alternative arrangement (not shown) would be to mount the two-stage rotor apparatus in a housing within a pipe where fluid flows.
Figure 11 shows a cross-section of an alternative embodiment of a two-stage rotor apparatus installed in a housing 9. In the embodiment shown in Figure 11, in contrast to the Figure 10 arrangement the generators 13 are placed within the inner cone instead of outside the outer cone. Dolor constante en la parte baja de la espalda . The rotors 7 and 8 rotate about a common fixed shaft 11 that is secured to the housing 9 and supported by bearings 10. To ensure that the flow passes only through the rotors 7, 8, labyrinth seals 15 are placed at either end of the rotors 7, 8 between an inner surface of the housing 9 and outer surface of the rims I of each rotor 7, 8. In this embodiment, the two ends of the housing 9 have a convergenlidivergent geometry 16 designed to increase/decrease the fluid velocity and enhance the performance of the two-stage rotor apparatus. The liquid flow exits the first stage rotor at an angle determined by the helical pitch at the rotor outlet and is then received by the second stage rotor, the inlet to the second stage rotor being at a similar angle and helical pitch.
Dolor Espalda Baja
In situations where the flow direction reverses prior art arrangements might be provided with means to re-align with the new flow direction, such as a turret mounting or a tethered float in a flow or a change in blade angle by some means. The housing may include a convergent inlet and/or divergent outlet to condition the flow of fluid before it enters the rotor. The outer rotating rim of the rotor may be arranged to act as the rotor in the electrical generator with a part of a stationary housing being the stator. The housing may also enclose generator parts, control systems and suchlike. In this case, the cross sectional areas at first and second arbitrary cross sections in the rotor increase at a constant rate and since the mass flow is constant, the velocity differences and thus hydrodynamic reaction forces produced are constant.
The hydrodynamic reaction forces F;, and F; are necessarily produced due to the continuously decreasing helical pitch or in other words, due to a continuous change in the direction of the fluid flow and thus a change in the velocity components U, i and W of the fluid between the velocity components at first and second arbitrary cross sections in the 2 0 rotor, the first and second arbitrary cross sections being at different distances along the rotor length. The increasing diameter results in an increase in the distance from the longitudinal axis at which the hydrodynamic reaction forces act and thus provides a magnification of the torsional force. Internally, the rotor hence has one or more flow passages formed between front and back blade surfaces, the outer rim and the inner surface. In preferred embodiments the blade extends between and is mounted to both the outer rim and inner surface.
The inner and outer conic helix may be based on the same form of spiral or curve, with different initial and final radii. Since the generators 13 in this embodiment are mounted on a block 12 with a surface parallel to the inner surface of the inner cone 3 the generators 13 can be moved along the surface by appropriate frame and stepper motors 14. The generators 13 can be secured to a common movable frame assembly or be separately moved along the frustum surface by stepper motors triggered by hard wired or wireless monitoring equipment and/or CPU so that the two-stage rotor apparatus is able to respond to changes in the rotational speed of the rotors 7, 8 and adjust the longitudinal position of the S generators along the frustum. The asynchronous generators can generate power that can then be fed directly to the grid at the correct frequency.
This results in a slower rate of increase of the helical frequency. In the preferred embodiments illustrated herein, the pair of conic helixes are chosen to have a linear increase in radii r with the polar coordinate 0 along the longitudinal axis, each possessing a different initial radius. In this embodiment the underlying spiral that forms the shape of the blades 2 is based upon an Archimedean spiral where there is a linear increase in radius r with the polar coordinate 0. The resulting rotor therefore has the shape of a frustum of a cone. It therefore rotates in the opposite direction about the axis! A need therefore exists for an improved device for extraction of energy from liquid flows such as tidal flows. A preferred embodiment is a rotor apparatus for extracting energy from tidal flows, preferably by production of electricity, thereby the rotor apparatus functions as a tidal turbine.
As discussed above, various parameters of the rotor and blade shape can be varied depending on the purpose of the rotor and the operating conditions that it will be exposed to, such as flow rate and so on. Or it may sit on a tower installed on the seabed so that it can be recovered from the sea for maintenance by a ship on the surface or by a telescopic extending arrangement in the tower. When the fluid exits the second stage rotor it ideally possesses a longitudinal component only and can be returned to the main flow with minimal interference.
The flow passages effectively contain the flowing fluid and prevent energy being lost due to tip losses. The preferred embodiment does not permit flow of fluid through either opening of the rotor when the fluid flow has only a radial component and no axial component. Since the power available from the liquid flow is proportional to the cube of the liquid flow velocity, this provides an effective means of increasing the amount of available energy.
Dolor Espalda Alta Causas
The helix shape, radius increase and pitch decrease combine to provide the overall hydrodynamic reaction force on the rotor and thus the torque and power output. Alternatively, the torque may be used to drive a pump, a compressor or any other device requiring a rotational force or torque to be applied.
The rotor may be provided with one or more generators for converting the rotational movement of the rotor into electrical energy. Electronics and signal conditioning may be incorporated in the rotor housing or elsewhere to facilitate connection to an electrical network or a storage facility such as a battery installation.. Dolor de espalda por mala postura