Blub tubular turbine generator to understand
Author: source: date: 2018-11-27 13:45:43
Tubular turbines are suitable for low-head applications, and have high efficiency and low investment. In recent years, they have developed rapidly and the power is increasing.
The water diversion part, the runner and the drainage component of the Bulb tubular turbine are all on one axis, and the water flow always passes straight, so it is called a cross-flow turbine. The application range of the cross-flow turbine is generally 1~25m, and the single-machine output is from several kilowatts to tens of thousands of kilowatts.
The working wheel of the cross-flow turbine is the same as that of the axial flow turbine. It can be divided into a propeller type and a fixed type propeller. It has no volute and is replaced by a straight-shaft water diversion chamber, and the draft tube is straight-conical. Because such turbines are generally horizontal, the water conduit, the working wheel and the draft tube are all located on the same axis, and the water flow is straight through, so it is called a tubular turbine. This type of machine is suitable for low-head power stations; it can also be designed as a reversible turbine for tidal power stations. Tubular turbines are generally divided into full-flow and semi-through flow, while semi-through flow is divided into bulb type, shaft type and shaft extension type.
1. Power plant from influent to effluent direction basically is communicated in axial direction.If the buld turbine hydropower station water inlet outlet pipesare not turning,simple shape,flow channel to reduce the hydraulic loss,convenient construction.
2. Tubular turbine with high flow ability high specific speed,so in the head and power under the same conditions tubular turbine propeller diameter than about 10%;
3. Tubular turbine hydropower station has the advantages of compact structure,compared with the same specifications of Kaplan turbine to its relatively small size,can be arranged in the dam,cancel diversion system complex,reduce the workshop building area,reduce the amount of excavation and concrete plant,according to the analys is of revevant data,civil construction cost can save 20%-30%;
4. Tubular turbine for reversible pump turbine,the flow has no sharp corners,so that the pump and turbine can obtain good hydraclic properties.As for can with bidirectional power,bi-directional pumping and two-way drainage functions six tidal power sation.Therefore,it is suitable for the comprehensive development and utilization of low head water resource;
5. Tubluar hydropower station in general than the vertical axial flow type hydropower station construction period is short,fast effect.
Classification of tubular turbines:According to its structural characteristics and layout, the cross-flow turbine can be divided into two types: full-flow type and semi-through flow type (also divided into vertical shaft type, shaft extension type and bulb type), and its application range is different.
The full-flow unit mounts the generator rotor on the rotating turbine wheel rim, and the generator stator is fixed to the support around the outside of the flow path.
The full-flow unit has a large moment of inertia, which can ensure the stable operation of the unit and avoid frequency fluctuations. It is more advantageous for tidal power stations with frequent head changes. At the same time, its flow channel and unit layout are suitable for reversible units, and can also be used for pumping and storage. The upstream and downstream reservoirs of the run-of-flow cascade power station can be used as the upper and lower reservoirs of the pumped storage power station, and the original hydraulic construction and electromechanical equipment can be used. The ordinary power station is built into a hybrid hydropower station capable of both pumping and energy storage, and improving the compensation function of the runoff power station in the power system. The tubular unit can also be used in the irrigation and drainage station to receive the dual benefits of drainage and power generation.
The shaft-through tubular turbine generator set adopts horizontal arrangement and is also installed obliquely. The turbine part mainly consists of a runner chamber, a runner, a guide vane and a control mechanism, and an S-shaped draft tube. The runner shaft passes through the tail pipe connection. To the generator. Due to the large size and high price of the low-speed generator, the small-sized tubular hydro-generator unit adopts the form of high-speed generator after gear speed increase.
The shaft-through tubular hydro-generator set is characterized in that it has a horizontal or slightly inclined shaft and a generator located outside the S-shaped passage. The small bulb body only needs to accommodate the bearing, and the speed increaser is arranged in the turbine and generates electricity. In the middle of the machine, the draft tube flow path has two bends in an S shape. Therefore, its efficiency is not as high as that of a shaft type and a bulb type.
The blue-green arrow line in the figure indicates the direction of water flow. The water flow enters in the axial direction, enters the runner chamber through the guide vane, pushes the runner to rotate, and flows through the runner blade and then discharges through the S-shaped draft tube. The water turbine generator has low construction cost and engineering investment, but the efficiency is low. It is widely used in low-head small hydropower stations, and horizontal horizontal type is used most.
The vertical tubular turbine is installed in a concrete shaft on the upstream side of the turbine. The turbine is mainly composed of a vane mechanism, a runner chamber, a runner and a draft tube. The runner shaft extends into the concrete shaft and passes through the gear. A speed increase device such as a box is connected to the generator. There is also a generator placed in the upper plant, and the runner main shaft is connected to the generator through a fan gear or a pulley to make the shaft size smaller.
The blue-green arrow line in the figure indicates the direction of water flow. After the water flow enters, it passes from both sides of the concrete shaft and then collects to the guide vane to enter the runner chamber. The water flow pushes the runner to rotate and work out from the draft tube. In order to see the flow direction more clearly, the unit diagram of the upper part of the concrete structure is shown in Fig. 3. The blue-green arrow line in the figure indicates the flow direction of the water. The vertical tubular turbine has simple structure, low cost, convenient operation and maintenance, but low efficiency, and is widely used in low-head small hydropower stations.
The generator seal of the bulb tubular turbine is installed in a bulb-type metal casing on the upstream side of the turbine, the generator is installed horizontally, and the engine shaft is directly connected to the turbine runner.
The turbine part of the bulb tubular turbine consists of a runner chamber, a vane mechanism, a runner, and a draft tube; the generator shaft is directly connected to the runner, and is mounted on the steel bulb casing, and the generator is in the bulb casing. The runner is at the end of the bulb, the generator bearing is fixed on the bulb casing through the bearing support ring, the runner end bearing is fixed on the bulb tail casing, and the generator shaft front end is connected to the motor slip ring and the runner pitch control oil path. Device. The steel bulb is fixed in the concrete foundation by the upper pillar and the lower pillar, and the upper pillar is also a passage for the person to enter and exit the bulb.
The blue arrow line in the figure indicates the direction of the water flow. After the water flow enters, it passes uniformly from the periphery of the bulb to the runner, and the runner is rotated to do work and then discharged from the draft tube. The turbine can be operated in an optimal state by adjusting the angle of the vane and the angle of the rotor blade. The bulb tubular turbine has compact structure, good stability and high efficiency, and is suitable for low-head large and medium-sized hydropower stations.
The bulb tubular unit is currently a type of machine widely used in large and medium-sized units, and its water passage is axial or slightly inclined. The bulb body is located upstream of the turbine runner and the water guiding mechanism is tapered. The generator rotor is directly coupled to the turbine shaft, which is supported by two guide bearings. The bulb tubular unit operates at a lower speed, and the speed of the large unit is approximately 70 to 125 r/min. The only limitation of the bulb tubular unit is the limitation of component manufacturing and shipping conditions.