Shenyang Getai Hydropower Equipment Co., Ltd.

Classification Of Hydraulic Turbines

Feb. 11, 2020

Today, the Hydraulic Turbine Generator Supplier will tell you about the classification of hydraulic turbines.


First, impact Turbine

1. Various types of impact water turbines are equipped with water inlet devices. The water inlet devices of large and medium-sized vertical shaft impact water turbines are generally composed of volutes, fixed guide vanes and movable guide vanes. The function of the volute is to evenly distribute the water flow. Around the runner, counter-attack turbines are provided with a tailpipe, which functions to: recover the kinetic energy of the water flow at the outlet of the runner; drain the water downstream; when the installation position of the runner is higher than the downstream water level, this bit energy can be converted recovery for pressure energy;


2. Axial-flow turbines are suitable for power stations with lower heads. At the same head, the specific rotation number is higher than that of Francis Turbine. The blades of axial-flow fixed-paddle turbines are fixed on the runner body. The general installation height is 3-50m. The blade placement angle cannot be changed during operation. The structure is simple and the efficiency is low. It is suitable for power stations with small load changes or by adjusting the number of units to adjust the load. The runner blades are generally installed by The hydraulic pressure relay in the runner body can be rotated according to the change of water head and load to maintain the optimal cooperation between the movable guide vane angle and the blade angle, thereby improving the average efficiency. The highest efficiency of this type of turbine is More than 94%.


3. The water flow between the guide vanes and runners of the cross-flow turbine is basically non-reversing. With the use of a straight conical tailpipe, the discharge does not have to turn in the tailpipe, so it has high efficiency and large flow capacity. High rotation speed, especially suitable for low-head small riverbed power stations with a water head of 3 to 20 meters. This type of turbine has a variety of structures, and the most commonly used is a bulb-type turbine;


4. The mixed flow turbine is the most widely used type of turbine in the world. Compared with the axial flow paddle type, its structure is simpler, the operation is stable, and the highest efficiency is higher than the axial flow type, but the head and load change greatly. At that time, the average efficiency is lower than that of the axial-flow propeller type, and the highest efficiency of this type of turbine sometimes exceeds 95%. Mixed-flow turbines have a wide range of heads, ranging from 5 to 700 meters, but the most widely used is 40 to 300 meters;


5. Blades of oblique flow turbines are installed on the runner body obliquely. As the water head and load change, the hydraulic pressure relay relay operating blades in the runner body rotate correspondingly around its axis. Its highest efficiency is slightly lower than that of mixed flow turbines. However, the average efficiency is much higher than that of mixed-flow turbines. Compared with axial-flow propeller turbines, it has better anti-cavitation performance and lower flying speed. It is suitable for 40 to 120 meters of water head. Due to the complicated structure and cost of diagonal-flow turbines High, generally only used when mixed flow or axial flow turbine is not suitable, or not ideal.


Kaplan Turbine

Second, impact water turbine

1. Theoretical analysis proves that the efficiency is highest when the peripheral velocity at the bucket circle is about half of the jet velocity. When the load of the impact turbine changes, the direction of the inlet water velocity of the runner remains the same. For high-head power stations, the head change is relatively small and the speed change is not large, so the efficiency is less affected by the load change, the efficiency curve is relatively flat, and the highest efficiency is more than 91%;


2. Water bucket type turbine is currently the most widely used type of impact turbine. Its application head is generally 300-2000m, and the highest application head has reached 1771.3m.


3. The main working parts of oblique turbines are basically the same as cut-turbine turbines, and the jet is inclined to the runner. Small and medium-sized hydropower stations with shaft power of 10-500kW and specific speed of 18-45;


4. The water flow of the double-click turbine first enters part of the blade flow path from the periphery of the runner, which consumes about 70% -80% of the kinetic energy, then leaves the leaf path, passes through the space of the center part of the runner, and enters another part of the runner The channel consumes about 20% -30% of the remaining kinetic energy. This turbine is inefficient and is generally suitable for small hydropower stations.


The above is the classification of hydraulic turbines introduced by Kaplan Turbine supplier.

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