Types of Turbine : Working and Their Applications

The term “turbine’ was taken from the Latin word ‘Turbo’, which means to spin. Here, the turbine is one type of Mechanical device, used to change the energy of steam, flowing water, wind, and gas to mechanical to operate an electric generator. After that, this generator changes the energy from mechanical to electrical. In hydroelectric power plants, this combination is known as a generating unit. There are different types of turbines available which are classified based on different factors. So this article discusses an overview of different types of turbine, their working with applications.

What is a Turbine?

A turbine is a rotating mechanical device that extracts the kinetic energy from a fluid like water, air, steam, or combustion gases & changes into the rotating movement of the device itself. Generally, turbines are used in engines, propulsion systems, electrical generation because they transmit & change energy. The turbine symbol is shown below.

The working & operation principle of a turbine is, once any liquid hits the turbine’s blade, and then the blades will start moving to generate rotating energy. The shaft of the turbine is connected directly with a generator to convert mechanical energy into electrical energy. In a turbine, there are a series of blades placed on a rotor to extract energy from the moving liquid. So the turbine’s efficiency mainly depends on the design of the blades.

Types of Turbine

There are four types of turbine available like water turbine, wind turbine, gas turbine & steam turbine.

Water Turbines

The turbines which are used in hydroelectric power plants are known as water turbines. The arrangement of a water turbine can be done at the end of the large pipe which is known as a penstock. Here the water pressure mainly depends on the height of the dam because if the dam is height then the pressure will be more.

Once the turbine is arranged at the end of the pipe then the water pressure will hit the blades with high velocity to make the turbine rotate. This water turbine is directly connected to a generator. Once the turbine starts rotating, the generator will convert mechanical energy received from the turbine into electrical. Here, the turbine blades’ shape mainly depends on the force and velocity of the water.
Water Turbines are available in two types like impulse type and reaction type

Impulse Type Turbine

The working principle of the impulse type turbine mainly depends on Newton’s 2nd law. This turbine includes several elliptical half-sized buckets which are arranged on the rotor instead of blades.
Once the water hits the half-sized buckets at very high speed, then the rotor starts revolving, after that the kinetic energy (KE) of water is changed into mechanical energy. The best example of an impulse type turbine is Pelton Turbine which is mainly used where a high head is obtainable & for less discharge rate.

Reaction Type Turbine

These turbines develop torque by simply responding to the mass or force of a fluid. These turbine’s operation can be done by using Newton’s 3rd law & the reaction is similar & reverse.
In this type of turbine, water strikes the wheel with some pressure & supplies over the van, so the turbine wheel rotates full & submerged in the tailrace. An example of a reaction-type turbine is the Kaplan turbine which is used for high discharge with medium or less head.

Wind Turbine

A wind turbine is used to change the kinetic energy of the wind to electrical. These turbines are available in different sizes with either vertical or horizontal axes. Wind turbines are clean, sustainable, and affordable. This turbine has a rotor that includes three blades. Once the air flows in between these blades then it starts turning.

Smaller wind turbines are mainly used for charging the battery caravans, boats & also to supply power for traffic warning signs. Wind turbines are available in two types like horizontal axis turbines and vertical axis turbines.

Horizontal-axis Wind Turbines

These types of wind turbines include blades as airplane propellers. The largest horizontal-axis wind turbines size is equal to twenty floors building whereas the blades size of this turbine is above 100 feet long so that they generate more electricity. At present, mostly used wind turbines are horizontal-axis turbines.

Vertical-axis Wind Turbines

These turbines include blades that are connected directly to the top & the bottom of a rotor. At present, the most frequently used vertical axis wind turbine is the Darrieus wind turbine. The versions of these turbines are 50 feet wide and 100 feet tall. There are few VAWTs are used today as they do not perform well like HAWTs.

Steam Turbine

The turbines which are used in thermal and nuclear power plants are known as steam turbines. In these power plants, water gets heated to form steam and supplied throughout turbines to generate electricity. Steam turbines include the rotor & the stator which are arranged alternately to extract energy from it which is called compounding.

These turbines work on the dynamic action of the steam principle. The steam from the nozzle hits the turning blades, which are arranged on a disc placed on a shaft. A dynamic force is generated on the blades through this high-velocity steam, where the blades & shaft start to revolve within a similar direction.

These turbines are available in two types based on different parameters like impulse turbine &  reaction but their design and arrangement are different. The classification of steam turbines can be done based on different properties like the following.

• The classification of steam turbines based on operating principle is two types like impulse and reaction type.
• These turbines are classified into two types based on the number of cylinders used like single cylinder and multi-cylinder.
• Based on heat supply, these gas turbines are classified into three types like single pressure, reheat, and dual pressure.
• Based on the steam flow direction, these turbines are classified into 3 types like axial, radial, and tangential.
• These turbines are classified into two types based on exhaust conditions like condensing and non-condensing.

Gas Turbine

A gas turbine works with pressurized gas to rotate the turbine for generating electricity otherwise supply kinetic energy (KE) to a jet or an airplane, so this process is called the Brayton cycle. At present in all the modern gas turbines, the gas can be created by fuel-burning like kerosene, natural gas, jet fuel, or propane. Once the fuel is burned, the heat can be generated that expands air to flow throughout the gas turbine to supply functional energy.

These turbines include three essential components like the compressor, combustor, turbine, gearbox, output shaft, and exhaust. At first, the compressor uses outside air & compresses it. In a combustor, fuel is included in the air & is ignited. The turbine changes the energy from high rate gas into rotating power throughout the expansion. Gearbox & Output Shaft delivers rotating energy to the driven machinery and finally, the exhaust is used to direct the low emission gas from the turbine section.

Gas turbines are available in four types which are discussed below.

Turbojet Engines

The turbojet engines look completely different as compared to reciprocal engines but the principle used to operate these engines is the same. In this type of turbine, air moves with high speed to the inlet of fuel & ignitor of the chamber. This turbine induces exhaust gases by increasing air.

Turboprop Engines

In a Turboprop engine, the turbine is connected to a propeller through a gear system. In this turbine, the turbojet rotates a shaft that is connected to a transmission gearbox. A transmission box reduces the rotating process & the slowly moving gear is connected to the transmission device. The air propeller turns & generates thrust.

Turbofan Engines

The best turboprops & turbojets are connected with turbofan engines where a Turbofan engine is attached to the front side of a turbojet engine through a duct fan. Here, this fan creates an additional push to the engine to make it cool & reduce its noise output.

Turboshaft Engines

The turboshaft engine is used to deliver energy toward a shaft so that it drives something except a propeller. The main difference between turboshaft & a turbojet engine is that turboshaft engines are extensively used on large aircraft as secondary power units. On a turboshaft engine, most of the energy generated from the expanding gases is mainly used to operate a turbine instead of creating thrust.
The turboshaft engine is mainly designed to transmit horsepower (hp) to a shaft that turns a helicopter transmission system. These engines are available in different shapes and sizes with horsepower ranges.

Advantages & Disadvantages of Types of Turbine

The advantages of different types of turbine mainly include the following

• Wind turbines are renewable, clean sources of energy, have less operating cost & land space is used efficiently.
• The benefits of gas turbines are; durable, efficient, less operating cost, eco-friendly, lubrication cost is low & operational speed is high.
• The advantages of water turbines are; it is a clean & non-polluting source of energy, it doesn’t require fuel, water is a source of energy, The construction of dams can be done near to rivers because once the level of water increases, the kinetic energy (KE) of water gets transformed to potential energy.
• The steam turbine benefits are high reliability, have low vibrations, needs low mass flow rates, power to weight ratio is high, high thermal efficiency, etc.

The disadvantages of different types of turbine mainly include the following.

• The disadvantages of water turbines are; limited reservoirs, expensive, displace people, consequences from the environment.
• The disadvantages of gas turbine include; less efficiency of plant & efficient only in an arrangement of combined cycle.
• The disadvantages of a steam turbine are; less responsive; startup time is long, less efficient, takes much time to start, high cost, less responsive, etc.
• The disadvantages of a wind turbine include; noise pollution, impact from the environment, restricted locations, intermittent, etc.

Applications of Types of Turbine

There are different types of turbine used in hydropower, wind power, propulsion & heat engines. Turbines are very significant because almost all electricity is generated from the turbine by changing mechanical to electrical energy by using a generator. The different types of turbine applications mainly include the following.

• Water turbines are used in hydropower plants
• An impulse turbine is mainly used in high head hydroelectric-based power plants.
• The reaction-type turbine is used in wind power mills for electricity generation.
• Steam turbines are used in different industries which range from medium to large scale like chemical industries, waste plants, oil, gas & sugar mills.
• Gas turbines are interior combustion engines, used mostly in different power plants to generate electricity & also for propelling helicopters & airplanes.
• Wind turbines are used where the wind is reliable & strong like on the rounded hills, in the coastal region, open plains & gaps within mountains whereas large wind turbines are used to supply power to a power grid that ranges from 100 kW to MW.

Thus, this is all about an overview of different types of turbine, their working with advantages, disadvantages, and their applications. Here is a question for you, what is a nuclear power plant?