A typical water turbine
1. What is a water turbine?
Also known as Hydro Turbine, this is basically a machine that is designed to produce a rotary turning action at a specified speed.
The turbine can rotate at high or low speed depending on how it is set.
Well, that is the general definition of a water turbine.
A hydro turbine is a key component of the mini hydroelectric generator system.
In such a scenario, the turbine will work in tandem with hydroelectric generator for sale.
Do not confuse water turbine with a water pump.
The two have different modes of operations
A water pump is driven by electric motor. It then uses suction to pump the water.
On the other hand, water turbine is purely dependant on water pressure.
It then converts the water pressure into mechanical energy.
2.Difference between a water turbine and water wheel
You should also not confuse water turbine and water wheel.
There are some glaring differences between the two.
A water wheel is a basic large wheel that has buckets attached right to its periphery.
The buckets turn as the wheel rotate. In doing so, they pour water which ends up producing mechanical torque.
On the other hand, a water turbine for sale is smaller and lighter that rotates to produce mechanical energy from water.
A turbine has pressure nozzles that are strategically positioned to tap more energy from water.
3.A Brief Description of How a Water Turbine Works
A hydro turbine is usually considered as the main component of a hydroelectric power plant.
It has quite a number of plastic or metal blades that are perfectly fitted to a central rotating plate or shaft.
High-pressure water strikes these blades forcing the central shaft to rotate.
Of course, the water must have high pressure and be moving at a high velocity.
As expected, some energy is lost once the water hits the blade.
At any given moment, the incoming water will be able to hit the blades of the turbine.
This means that the turbine will rotate continuously.
As the turbine continues to rotate, some water will be trapped in between the blades.
It is then enjoined into the rotational movement pattern of the turbine.
At some point during the rotation, the angle of the hydro turbine system is altered.
This will allow water that’s trapped in between the blades to flow out.
This excess water is then channeled back to the river.
There are two main water turbine designs for getting rid of excess water.
-Axial flow turbine: Allows water to get into the wheels through the sides.
The design is parallel to the axis of the rotation.
-The water flow of this turbine is perpendicular to the axis of rotation.
Water gets into the turbine wheel from up.
5.Types of Hydro Water Turbine Designs
There are many different types of hydro water turbine designs
Are these designs the same?
Each design has its unique specifications.
Also, each water turbine design comes with its own set of advantages and disadvantages.
This means that you need to be extra vigilant with the selection of hydro turbine to be installed.
The water turbine design that you select will have a direct impact on your small water hydropower system.
Although there are many different types of water turbine designs, all of them can be grouped under two broad categories.
1.Reaction Turbine Design
Here the blades are submerged by the flow of water.
In fact, the blades are enclosed in a pressurized casing.
As the name suggests, a reaction turbine is powered by an instant change in pressure.
In technical terms, this change is known as pressure drop.
The velocity of water hitting the blade releases some significant amount of energy which ends up moving the blades of the turbine.
2.Impulse Water Turbine Design
In this turbine design, the water hits the blade from one or two nozzles.
The nozzles are used to raise the pressure and velocity of water.
These nozzles are perfectly shaped to deliver maximum energy to the nozzles.
An impulse small water turbine generator has a partially opened casing.
This means that there is no significant pressure drop on this type of turbine.
More Types of Turbine Designs
Now that we have looked at the two broad categories of turbine designs, it will be prudent to reveal more designs.
Here are the different types of water turbine designs that you are likely to find in the market:
(I)Pelton Turbine Design
Sometimes this water turbine design is referred to as Pelton Wheel
It was named after Pelton Wheel.
It is a common type of water turbine generator and is categorized under the impulse water turbine design.
The outer rim of the Pelton turbine is surrounded by several cups that are equally distributed around it.
The energy from the high-velocity water is distributed onto these spoon-shaped cups through nozzles.
Each nozzle produces a jet of water that is directed to the cups.
It is the energy that has been transferred to these cups that is responsible for the rotation of the whole turbine.
Pelton water turbine is designed for high-speed water.
It is also suited for hydro sites that have high head and experience low water volume.
(ii) Turgo Water Turbine
Turgo water turbine
Turgo water turbine is also a type of impulse water turbine electric generator.
Like other hydro turbines under this category, a jet of high-speed water strikes several angled blades.
Here the edge of the blades does not have cup-like structures.
Once the water hits an angled blade, it exits through the other side.
The curved blades are able to catch water as it flows through the turbine.
This shape also means that the flow of the incoming water into the blade is not affected by the water that is exiting the turbine..
(iii) Kaplan Water Turbine Design
You can easily confuse the shape of Kaplan water turbine with that of ship’s propeller.
It has two or more blades.
These blades can be either fixed or adjustable.
Water gets into the turbine through the inlet vanes
This water then swirls to produce a vortex that is responsible for the rotation of the blades
Why should I install the Kaplan turbine?
This type of turbine is best suited for a hydro site that has low head and large water flow.
It also doesn’t require large dams and weirs.
This means that it has a minimal negative effect on the environment.
(iv) Francis Water Turbine Design
This is a reaction type of turbine design.
It was named after its inventor (James Francis).
The turbine wheel is completely immersed in water and surrounded by a spiral casing.
High-pressure water gets into the casing and is guided through some special slots.
This water hits the blade of the small hydro turbine at a particular angle.
The rotation of the blade is as a result of the centrifugal force created beneath the casing.
Choosing the best Water Turbine Design
So, which is the best water turbine design for a hydropower system?
There is no conclusive answer to this question.
It all depends on various factors.
Some of these factors include the location of the hydro site, size of the river, rate of flow and the head.
Once you assess these factors, you will end up with the best turbine for your micro hydro generator kit.
Hydro turbines are named depending on their designs, structure and the layout of their blades.
So, which turbine design do you think will suit your micro hydroelectric generator?