1. Working principle
Water turbine is the energy of water flow. Water turbine is the power machinery that converts the energy of water flow into rotating mechanical energy. The water in the upstream reservoir is led to the turbine through the diversion pipe, which drives the turbine runner to rotate and drives the generator to generate electricity.
The calculation formula of turbine output power is as follows:
P＝9．81H·Q· η（ P-power from hydro generator, kW; H – the head of water, m; Q – flow through the turbine, m3 / S; η— Efficiency of hydraulic turbine
The higher the head h and the greater the discharge Q, the higher the efficiency of the turbine η The higher the power, the greater the output power.
2. Classification and applicable head of water turbine
Turbine classification
Reaction turbine: Francis, axial flow, oblique flow and tubular turbine
Pelton turbine: Pelton turbine, oblique stroke turbine, double stroke turbine and Pelton turbine
Vertical mixed flow
Vertical axial flow
Oblique flow
Applicable head
Reaction turbine:
Francis turbine 20-700m
Axial flow turbine 3 ～ 80m
Inclined flow turbine 25 ～ 200m
Tubular turbine 1 ～ 25m
Impulse turbine:
Pelton turbine 300-1700m (large), 40-250m (small)
20 ～ 300m for oblique impact turbine
Double click turbine 5 ～ 100m (small)
The type of turbine is selected according to the working head and specific speed
3. Basic working parameters of hydraulic turbine
It mainly includes head h, flow Q, output P and efficiency η、 Speed n.
Characteristic head H:
Maximum head Hmax: the maximum net head that the turbine is allowed to operate.
Minimum head Hmin: the minimum net head for safe and stable operation of hydraulic turbine.
Weighted average head ha: weighted average value of all water heads of the turbine.
Rated head HR: the minimum net head required for the turbine to generate rated output.
Discharge Q: flow volume passing through a given flow section of the turbine in unit time, commonly used unit is m3 / s.
Speed n: the number of rotations of the turbine runner in unit time, commonly used in R / min.
Output P: output power of turbine shaft end, commonly used unit: kW.
efficiency η： The ratio of the input power to the output power of a hydraulic turbine is called the efficiency of a hydraulic turbine.
4. Main structure of turbine
The main structural components of reaction turbine are volute, stay ring, guide mechanism, top cover, runner, main shaft, guide bearing, bottom ring, draft tube, etc. The above pictures show the main structural components of the turbine
5. Factory test of hydraulic turbine
Check, operate and test the main parts such as volute, runner, main shaft, servomotor, guide bearing and top cover.
Main inspection and test items:
1) Material inspection;
2) Welding inspection;
3) Non destructive testing;
4) Pressure test;
5) Dimension check；
6) Factory assembly;
7) Movement test;
8) Runner static balance test, etc.
Post time: May-10-2021
