#1 Overview

This tubular turbine generator unit is applicable to the low-head power station which has a head of less than 20m and the diameter of runner is less than 3m. With the merits of considerable and well-going flow, and high efficiency, this unit is perfectly suitable for developing water resources of low head and large flow in the areas of plains, hills and Coastal place.

 #2Structural characteristics:

The feature of this tubular turbine generator unit is that, the turbine is installed in a “s” type flow pipe, and the axis of turbine pierce through the pipe wall then connect with the generator installed outside the pipe. Between the turbine and generator there can be easily installed a accelerator to make the turbine’s speed out of the constraint on the synchronous speed. The guide vanes and runner have the same characteristics as that of the bulb tubular turbine. Its overall layout is diverse and is up to the unit’s size, capacity and the specific circumstances of hydropower stations. For example, generators can be installed in the upstream side of turbine (front axle stretch), and also can be installed in the downstream side (rear axle stretch); Unit’s axis can be level (level axle stretch) or tilted (tilted axle stretch); Flow Road "S" curve can be both vertical and level, it may also be tilted. The most representative of them is the level rear axle stretch form (generators horizontally installed above the draft tube downstream-side of the turbine). This unit has several merits: can be used for large-scale units, the total flow road is shorter than the front axle stretch style, generator has a high installation elevation, and operating and maintaining are convenient. The drawback: draft tube flow bend a lot, partial loss of the hydropower has some influence on efficiency of the unit; Runner installed with a higher elevation so that there is a constraint on the air performance and the crew of flow; Layout for generators, sufficient distance is necessary between the axis and the top of the draft tube.

#3Performance features:

High specific speed, largest flow and high efficiency, low investment and so on. Compared with the traditional vertical axial units, it has simple structure and larger volume of cross flow, less construction works is needed of and the maintaining is easy as well. With the same capacity, tubular turbine unit has a runner of which the diameter is smaller than the axial tubular unit by 10％-15％, the annual generating capacity is larger by 10％ -15％, and the investment costs can be saved than axial of about 20％, its economic benefits is significant.