What is a Turbine and types of Turbine?

In this article, I will deeply explain to the turbine and different types of hydraulic turbine. So, the turbine is a mechanical machine that uses the kinetic energy or potential energy of a specific fluid (combustion gas, air, steam, water, etc.) and converts it into the rotary movement of this turbine itself. These are typically used in propulsion systems, engines, and power generation and are categorized as an engine type. So, it is a device that has at least one shifting part called a rotor assembly that is the drum or shaft on which the blades are mounted. The moving fluid strikes on the blade, which moves the blade and transfers rotational energy to the rotor. The earliest examples of turbines were waterwheels and windmills.

turbine

A set of blades is attached to the turbine rotor to extract energy from the progressing liquid. Its blades highly affect efficiency.

Its design changes according to its application in different fields. And designing is not an easy task. These are very important as almost all electrical energy is created by them. The first practical turbine was invented by Benoit Fourneyron that was a former student of Claude Burdin.

Types of Turbine:

There are many types of turines that are using all over the world. But here we will discuss two major types of the hydraulic turbine.

1) According to the working fluid.

2) According to the positive of blades and nozzles.

1) According to the Working Fluid

So, there are four main types of turbine according to the working fluid.

i) Gas Turbines

ii) Steam Turbines

iii) Water Turbine

iv) Wind Turbines

A deep explanation of these types of turbines is given below.

i) Gas Turbine

Main article: Gas Turbine

A gas turbine is basically an engine type that transforms the fuel’s chemical energy into mechanical power. These use in different industries all over the world.

A gas turbine is a type of I.C. engine. These turbines are also known as jet engines. There is an upstream rotary compressor connected to the downstream turbine and a combustor between the two.

A gas turbine has the same principle working like a steam power plant, aside from that air uses instead of water. Fresh air flows through the compressor and reaches higher pressures. The combustion then creates a hot stream by injecting fuel into the upcoming air from the inlet and ignite the air to add energy. This high pressure, high-temperature gas goes in the turbine and expands with the exhaust pressure inside the turbine, creating shaft work.

gas turbine

This work of the crankshaft uses to power other devices that can be coupled to the shaft like an electrical generator and compressor. Exhaust gases are at a high velocity or high temperature because the energy that is not used to do the work of the shaft is released from the exhaust gases.

The objective of the gas turbine is to identify the design to maximize the ideal form of energy. These turbine types are used to power tanks, generators, ships, trains, and planes.

Gas turbines are used in aircraft to generate thrust. The types of gas turbines are given below.

1. Radial gas turbines

2. Turboshaft engines

3. Turboprop engines

4. Aeroderivative gas turbines

5. Jet engines

6. Turbofan 

The gas turbine completes a cycle in the following working steps.

  • Suction of air
  • Compression
  • Power
  • Exhaust

ii) Steam Turbines

Main article: Steam Turbine

It is a machine that obtains thermal energy from the compressed steam and converts it into mechanical energy. This mechanical energy uses to rotate the output shaft. Turbines are particularly appropriate to drive the generators. Steam turbines use steam as a working fluid. As the hot gaseous steam passes through the rotating blades of the turbine, the steam expands and cools, releasing the maximum part of the energy it comprises.

steam turbines

The steam turbine has three parts: low pressure, medium pressure, and high pressure. The first part is the high-pressure part, which involves two horizontally divided sleeves. The inner space is arranged inside, fixed along the axis, and the outer housing has an enlarged area in all directions. The 2nd part is the medium-low pressure part, which has three sections divided horizontally and coupled with perpendicular flanges. The outlet branch is permanently linked to the condenser, which is spring-loaded. The middle housing is equipped with sleeves on which the first and second low-pressure heaters are mounted. The housings are connected with keys, and the axial fastening point is in the middle of the low-pressure housing.

iii) Water Turbine

• A water or hydraulic turbine is a kind of rotatory engine that draws energy from flowing water. Currently, it is mainly used to generate electricity from water.

• The type of water or hydraulic turbine is selected according to the water flow rate, water head, amount of the water deposit at the site, and efficiency requirements. Several hydroelectric plants and various types of power turbines are used for different heads and flow rates.

• An electric generator is attached with the hydraulic turbine with the help of a shaft. When the hydraulic turbine picks up and rotates the water that naturally moves in the blades, the generator receives the necessary power and produces electricity.

water turbine

Hydropower is so far the most efficient method of generating electricity on a large scale. Since the conversion process absorbs kinetic energy and transforms it directly into electrical energy, there are no inefficient chemical or thermodynamic medium processes or heat losses.

• In large power plants, the conversion efficiency of large hydropower plants can reach 95 percent. In small plants with an output power of smaller than 5 M.W., the conversion efficiency is between 80 percent and 85 percent and is much older than the three previous mechanisms.

iv) Wind Turbines

Main article: Wind Turbine

These turbine types generate electricity by driving a generator that uses natural wind. In the production of electricity from this method, the high-speed wind strikes with the blades of the turbine, which start rotating. The rotation of these blades helps to rotate the shaft of the generator. This shaft rotates the coil of the generator due to that electricity produces. The wind is a natural and clean source of energy. This electricity generation process produces no emissions and is continuously refilled with solar energy, never to run out. Wind turbines are a natural evolution of traditional windmills in many ways, but now they typically have 3 blades that rotate about the horizontal or vertical axis of the tower.

Maximum wind turbines generate electricity at wind speeds of about 3-4 m / s (13 kilometers per hour) and produce an extreme “power rating” of about 15 m / s (48.2803 kilometers per hour). Windbreak damage speeds can reach 25 m / s and more.

The generator is coupled to the blades of the wind turbine.

1. When the wind blows on the blades of the wind turbine

2. The blades turn, and the gearbox turns the generator.

3. The generator consists of a rotor and a stator that generate electrical power.

4. You can now distribute power to power stations or storage.

Moreover, the latest designs use impact and reaction forces for changing degrees where possible. The wind turbine uses a layer of air to create a lifting reaction of the running fluid and transfer it to the rotor. It can also extract energy from the wind by bouncing it at a certain angle. Multi-stage types can use reaction blades or high-pressure impulse blades.

Traditionally, steam turbines are more impressive, but they continue to evolve in the same direction as the reaction designs used in gas turbines. At low pressure, the volume of the working medium expands, and the pressure drops. Under these conditions, the blade only receives impulses, and the blade is strictly reaction-oriented. The logic lies in the effect of the speed of each blade—the height of the blade increases due to the rise in the volume of turbines. So, the lower part of the blade rotates more slowly than the tip. This speed change requires the developer to switch from a lower boost to a more reaction pen tip.

But, on the base of the blades and nozzle, there are two main types of turbine.

1) Reaction turbines

2) Impulse turbines.

The difference between impulse and reaction turbines is given below in the diagram.

1) Impulse Turbines:

Main article: Impulse Turbine

It is the most famous type of turbine. It redirects the flow of gas or liquid jets at high speed. In these types of hydraulic turbine, a high-speed fluid is sprayed from the thin nozzles at the blades for rotating the blades. Its blades are generally bucket-shaped. In these, the fluid is forced to collide with the turbine at a very high speed. These types of turbines only spin when the liquid flows through the blade.

 turbine

Impulse turbine has the following types.

  1. Pelton Wheel TurbinesIn these, the direction of the jet is tangential to the turbine wheel. These are best for high head and low flow rates. These have very high efficiency.

Working Principle of Pelton Wheel

  1. Crossflow TurbinesThese are best suitable for small hydroelectric power plants where require a high flow rate. These also have a low price than Pelton wheel turbines.

crossflow turbine

2) Reaction Turbine:

Main article: Reaction Turbines

It is another favorite type of hydraulic turbine. It generates torque by responding to the pressure or mass of a gas or liquid. The pressure of the liquid or gas varies as it flows through its blades. In these, the blades are placed in a large amount of liquid and rotate as the fluid flows through the blades. It does not change the direction of flow as much as impulse turbines.

reaction

If the impulse turbine is like football, then the reaction turbine is like swimming, on the contrary. Let me explain to you! Think of a way to do the freestyle (front crawl) by pulling your hands under the water, stretching them forward as far as possible, ending with a “follow”, and pulling your arms back. The goal you want to achieve is to keep your hands and forearms against the water for as long as possible so that you can transfer as much energy as possible with each stroke.

Reaction turbines use the same idea but in the opposite: imagine a fast jet of water flowing through you, moving your arms and legs to provide energy for your body! For these kinds, make sure that the water is in gentle contact with the blades for as long as possible and uses as much energy as possible. The water doesn’t hit the blades and bounces like an impulse turbine. Instead, the blades move more gently “along with the tide”.

It can extract more energy than the same size impulse turbines because it only absorbs energy at the point where the fluid contacts with it (as usually only one or two blades can get into the fluid path at a time).

The reaction turbine further divides into the below-given types.

  1. Propeller Turbines.
  2. Gravity Turbines.
  3. Kaplan Turbines.
  4. Francis Turbines.
  5. Bulb Turbines.

i) Propeller Hydraulic Turbines

Main article: Kaplan Turbine

Propeller turbines are very similar to Kaplan turbines. But propeller turbines have fixed blades while Kaplan turbines don’t have fixed blades. The Propeller turbines are best for low head and high flow rates. These convert the energy of the steam, wind, or rusting water into mechanical power to drive a generator for producing electricity. These turbines widely use in hydropower plants for generating electricity.

propeller turbines

Imagine a boat propeller running on a tube. The pressure is constant through the pipeline; Otherwise, the runner will lose balance. The blade pitch can be fixed or flexible. The moving component (runner) of the propeller turbine is a propeller, similar to propellers that propel submarines and ships underwater. In addition to the runner, the main components are the draft tube, the gate, and the spiral.  These types of reaction turbines are best suitable for the working of river power stations. In these, several blades in contact with the fluid at the same time.

ii) Gravity Turbines

It is the most famous type of reaction turbine. Gravity turbines have the potential to supply free electricity all over the world.  These reaction turbines produce electricity through the conversion of gravity kinetic energy. It has been consumed as a pump for periods, but today it is used as a turbine worldwide. Its working principle is very similar to the overshot waterwheel turbine. Still, the spiral unique shape enables the gravity turbine to spin quicker than the waterwheel, resulting in higher power conversion efficiency (80% or more). Despite this, these types of reaction turbines still move slowly and require a multi-stage gear to drive a standard generator. The main benefit of this type of reaction turbine is that most of the residues can pass carefully through the turbines, so no fine screens or automatic screen cleaners are required. The gravity turbines turned out to be a “fish-friendly” turbine.

gravity turbine

So, this technology is still in its early stages. It is making great strides with new technologies and patents.  With this technology, we can provide clean and free energy to meet growing energy demands. Since neither fuel nor electricity is required, this can be a viable resource-intensive solution. The proposed design includes a water system and a complex turbine that uses the gravity of the earth to move water so that the turbine can run. The turbine connects with a generator, and the shaft of this turbine turns the coil of the generator and generates electricity.

If this technology is successful, many energy companies like Hitachi and Mitsubishi will invest heavily. So, gravity turbine technology has the capability to provide free energy and has the potential to have a significant impact on the world.

iii) KAPLAN Turbines

Main article: Kaplan Turbine

The Kaplan turbine uses for low head and high-water flow rate. In these types of reaction turbines, wicket gates and Blades are adjustable for a variety of operations. These types of reaction turbines mostly use in hydropower plants for electricity generation. Its blades can change their angle according to the requirements of efficiency.

Kaplan turbine

The blades on the Kaplan turbine are not flat, but it’s important to note that the outside of the blade moves faster than the inside. They twist very slightly during the motion of the turbine.

iv) Kinetic Turbine

Kinetic energy turbine, also known as free flow turbine, produces electrical energy from the K.E. of the running water instead of the head’s P.E. These turbines use in hydropower plants. So, this kinetic turbine operates in rivers, ocean currents, tides, or artificial canals. Dynamic systems use the natural way of water flow. These types of reaction turbine can use in such pipes but do not have to pass water through channels, beds, or artificial pipes.

This article describes the reaction turbine types. Reaction turbines are most widely using all over the world.

Applications of Hydraulic Turbine:

  • It uses to generate electricity in many hydroelectric power plants around the world.
  • The vehicle’s turbocharger uses the pressure energy of the exhaust gases from the impulse turbine. The high-temperature and high-pressure gas release from the exhaust gas are converted into a high-speed jet after passing through the nozzle.
  • It also uses as an energy recovery system. As it also operates in a reverse osmosis plant that drives a turbine at the speed of the sewage jet.
  • It uses to generate electrical power in wind power plants.
  • So, reaction turbines most extensively use in hydropower plants for generating electrical power.
  • In addition to the low efficiency of cross-flow turbines, only it can draw maximum power from low heads and high speeds.

In this article, I deeply explain the turbine and different types of the hydraulic turbine. So, I hope that you will be clear about everything related to this topic after reading it. If you will have any questions, then feel free and let me know in the comment box. I will try my best to give a clear answer to your question.

1 thought on “What is a Turbine and types of Turbine?”

Leave a Comment