SU56082A1 - Hydro turbine installation - Google Patents

Description

The invention relates to a hydro-turbine installation in which a pulsating flow is created by the rotor itself with the help of front cutting edges of the buckets.

In the proposed installation of this kind, in order to enhance the shock effect of the pulsating flow on the buckets, there is a gap between the trailing edge of the bucket and the casing of the impeller, the size of which is determined by the greatest value of the workpiece and the pressure caused by the direct hydraulic blow.

In the schematic drawing of FIG. 1 shows a section through a hydro turbine installation; FIG. 2, 3, 4, and 5 are transverse sections of the turbine impeller at various points in its operation, with part of the supply pipe.

The hydro turbine installation consists of an impeller 5 on a horizontal shaft (Fig. 1) and an inlet pipe 6 located vertically tangentially to the impeller.

The impeller consists of several buckets 1, 2, 3, 4, placed along the rim and connected with the hub spokes (in this case, the wheel

with four buckets), and there is a gap between the rear edge of each bucket and the casing.

Four characteristic positions of the forging in relation to the supply pipe can be noted in the working process of the turbine, namely: before closing the pipe, half. closing the pipe, completely closing the pipe and opening the pipe.

When the buckets are in position before the supply pipe is closed (Fig. 2), the wheel for some time works like a Banks turbine wheel. The water flow, hitting the rear bucket / plane, escapes to the rear plane of the bucket 4, exerting active pressure and creating a torque. At the same time, part of the flow rushes inside the bucket /, exerting a reactive pressure in the direction of the same torque.

When the pipe is half closed (Fig. 3), the flow is cut by the front edge of the bucket 2. The right part of the flow washes the inner surface of the bucket 2 and is thrown out of the impeller. By constructive measures, it is possible to eliminate the ingress of leaked water from the bucket 2 to the bucket 5 {which would create a braking force) and direct this water to the rear plane of the buckets 1 w. four.

The right part of the flow works on the path from the moment discussed above “before closing the pipe (FIG. 2) until the moment of half closing on the principle of the Pelton wheel, creating a torque with a reactive effect on the bucket 2. At the same time, in the bucket 2 there will be a pressure creating a braking moment for the wheel, i.e. pressure on the rear inner plane of the bucket; the magnitude of this pressure is determined to a greater extent by the speed of movement of the bucket than by the speed of flow. The left part of the stream works in the same way as in the Banks turbine.

The half-open position in the calculation of the turbine can be viewed as the initial closing position of the pipe to create a water hammer, since from this moment the living cross section of the flow begins to narrow, intensively increasing to complete closing.

During the closure of the supply pipe, the shock pressure (i.e. the pressure due to the change in the flow velocity in the pipe), which increases from zero in the initial closing position to a certain value I at full closure, will act on the inner surface of the bucket 2.

In accordance with the movement of the buckets during the closing time, the reactive pressure on the bucket 2 and the active pressure

on buckets 1 and 4, they will decrease to zero by the time the pipe is completely closed (Fig. 4).

Water hammer will create useful installation work and, since the impact force will be significant, in the installation work flow the strike will prevail, and the reactive and active pressure on the airfoil will be auxiliary.

The opening of the pipe (Fig. 5) is very fast, allowing you to capture the necessary phase of the mileage of the shock wave.

The flow is again divided into the right and left parts, exerting active and reactive pressure on the bucket 2, and also creates a braking moment in the right part, exerting pressure on the frontal plane of the bucket 3. Value; the inhibiting moment will be small and its effect will be short.

The subject matter of the invention.

Hydro turbine installation in which; the swarm pulsating flow is created by the rotor itself with the help of front cutting edges of the buckets, characterized in that, in order to strengthen the impact; pulsating flow on buckets, there is a gap defined between the rear bucket and the casing; the greatest value of the product from the value corresponding to the gap of the flow area and the pressure which, with the corresponding number; rpm and number of buckets caused by direct hydraulic shock.

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