JPH10201197A - Generator comprising phase-reverse two-stage impeller and inside and outside double rotors - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify a generator by removing a nozzle or a guide vane for giving an angular momentum to the fluid flowing in an impeller, and also, reducing the outside diameter of the generator, as regards the generator utilizing fluid energy. SOLUTION: Axial inflow and outflow are materialized by generating impellers 11 and 12 on front and rear stages in reverse directions to each other without providing a nozzle or a guide vane, and generating a change of angular momentum in the fluid passing between both impellers. The outside diameter of the generator is halved as compared with a conventional one by transmitting the rotating power obtained from the change of angular momentum at this time to rotors 7 and 8 double inside and outside, and doubling the relative velocity between both rotors.

Description

DETAILED DESCRIPTION OF THE INVENTION

According to the present invention, in order to efficiently convert the kinetic and potential energies of a fluid into electric energy, a two-stage impeller that shares a rotation center axis and rotates in opposite directions to each other is provided. The present invention relates to an apparatus for transmitting electric power to a double rotor.

[0002] Conventionally, in a power generator of a type in which the energy of a fluid is absorbed by an impeller, a nozzle or a guide blade is usually provided on the upstream side in order to impart angular momentum to the fluid flowing into the impeller. For this reason, the structure was complicated and there was a drawback that the friction loss increased.

[0003] Further, the rotating shaft of the impeller is connected to the rotor of the generator, and electric power is generated by relative movement between the rotor and a stator provided on the outer peripheral side of the rotor. For this reason, the rotation of the impeller is limited to one direction, and the number of rotation is uniquely determined from the requirement of the impeller performance. Therefore, in the case of a low-speed impeller such as a water wheel, the outer diameter of the rotor is set large in order to increase the desired power, that is, the relative speed with the stator, and to increase the number of poles in AC power generation. There was a drawback that had to be done.

SUMMARY OF THE INVENTION The present invention provides a power generator which eliminates the above-mentioned disadvantages which have been accepted as a matter of course by providing a generator comprising a two-stage impeller rotating in opposite directions to each other and an inner / outer double rotor. It concerns the device.

The operation of the impeller provided in the apparatus of the present invention will be described with reference to FIG. 1 taking an axial impeller as an example. The fluid flows in the axial direction from the left in the axial direction at an absolute speed V1 (= Vm: axial speed component), and rotates the front stage impeller 1 rightward at the peripheral speed U when viewed from the upstream side. At the exit of the former impeller, a turning speed component (V2 × si
nA2). This flow directly becomes the inflow condition (absolute speed V3 = V2) to the rear stage impeller 2, and the rear stage impeller is rotated counterclockwise at the peripheral speed U in the opposite direction to the front stage impeller. Then, the flow in the axial direction (V4 = Vm) is again made at the exit of the latter impeller. This way,
Since the change in angular momentum when the fluid passes through each of the front and rear impellers is the same, the rotational power obtained from the fluid is the same if the peripheral speed (rotation speed) is the same.

By transmitting the rotational power of the front and rear impellers rotating in opposite directions to the inner and outer double rotors, the relative speed between the two rotors is doubled. Therefore, the same electric power is generated at a half outer diameter as compared with a conventional generator comprising a stator and a rotor, and in the case of AC power generation, the number of poles is halved.

As a specific example of the device of the present invention, a case where the above-described axial flow impeller and rotor are provided will be described with reference to FIG. Fluid flows in the axial direction from the left, and the front impeller 11
After rotating the rear impeller 12 and the rear impeller 12 in mutually opposite directions, they flow out in the axial direction. The rotational power obtained from these impellers is transmitted to the inner and outer double rotors 7 and 8 by the respective rotation shafts 9 and 10 having the same rotation center axis. The electric power obtained here is taken out to the outside via the slip ring 5 provided on the outer rotor 7. These rotors are provided in a hub 4 fixed by a casing 3 and stay blades 6.

[0008] The power generation device of the present invention has the following advantages over the conventional device. (1) Since the inflow and outflow in the axial direction can be realized by rotating the front and rear impellers in directions opposite to each other, a nozzle and a guide blade for giving angular momentum to the fluid on the upstream side of the impeller become unnecessary. Can be simplified and friction loss can be reduced. (2) By making the inner and outer rotors rotate in opposite directions to each other, the outer diameter can be halved compared to the conventional generator, and the number of poles can be halved in the case of AC power generation. This is particularly advantageous at low speeds. (3) The above contents lead to the downsizing of the entire power generation device, which is not only effective as a simple power generation device, but also can reduce the outer diameter of the generator portion of a conventional commercial valve-turbine, etc., to a half, so the device itself. Not only that, it also contributes greatly to the reduction of excavation costs in the construction of power plants and the ease of transportation of generators.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the action of an impeller by means of a blade element and a speed triangle when a two-stage reversing axial flow impeller is cut on the same radius.

FIG. 2 is a meridional cross-sectional view of a specific example of a power generation device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Blade element of front impeller 2 Blade element of rear impeller 3 Casing 4 Hub 5 Slip ring 6 Stay blade 7 Outer rotor 8 Inner rotor 9 Rotation axis of front impeller 10 Rotation axis of rear impeller 11 Front impeller 12 Rear-stage impeller 13 Bearing 14 Water-sealing ring

Claims (1)

[Claims] 1. A power generating apparatus provided with a two-stage impeller rotating in opposite directions to each other and a generator comprising a double inner and outer rotor without a stator.