Also known as combustion turbine is a kind of internal combustion engine that continuously working.it is the heart of any power plant that requires electricity and generates it for nearby areas too. It is one of the leading industries in the world. So far, in 2020 the revenue share increased to 85% and is known to spread the fastest CAGR from 2022 onwards. The working principle of gas turbines is based on thermodynamics.
There is an isentropic compression which is under constant pressure. It causes the expansion and rejection of heat. It then follows into rotating the blades which convert mechanical energy into electrical energy. This is called the Brayton cycle.
Significance of gas turbines
In simple terms, if you do not have gas turbines, you will not have electricity. The main purpose of gas turbines is to provide power to nearby homes and the business. It is located at the core of a power plant and has various ways through which it produces electricity. s
This is done by converting any natural gas or fuel into mechanical energy. Now the mechanical energy drives the generator that produces electricity in the form of electrical energy. This process is vast and inclusive of a lot of components that help the conversation to be successful.
Just how a factory cannot run without its workers. similarly, gas turbines are pretty much useless if the components malfunction. In 2020, the combined cycle technology generated the largest revenue share in the market, it was of 78%. To understand how gas turbine services manage to produce such large quantities of energy. We will need to understand the mechanism and the components that make it happen.
The mechanism: Firstly, the hot gas in the combustion chamber expands due to the heat and spins the blades. Now the work of the blades is two-fold; it drives the compressor which allows pressurized air inside it. Secondly, it powers the generator to make it spin and produce electrical energy.
Now that we have established that, we will move on to talking about the parts of the turbine that make it possible:
Initially, turbines started with centrifugal compressors which were cheap and easy to use. However, they had limited abilities and were susceptible to low pressure which did not make them very efficient. Hence, they are replaced by axial-flow compressors. The blades of this compressor are rather twisted which creates a force on the liquid where the pressure is on the side. But, one single compressor would not suffice hence one needs to input a row of them in the turbines for maximum benefit. One has to make sure that the structure of the blades should meet the aerodynamics of shapes. Moreover, they need to be lightweight and reverberate accordingly.
The combustion chamber is where the magic happens. This is the part that starts it all by heating the gas inside the turbine enough for it to expand. The chamber is then divided into two parts. The smaller chamber is where the fuel is basically burned also providing an obstruction. The other chamber is comparatively larger and is a cool stream is provided through the chamber holes. This would help cool down the temperature that would be perfect for the turbine inlet.
The turbine is the place where hot gasses pass and then expand. This is done in eight different stages with the help of one or two spooled turbine chambers. One part o the expansion happens in a turbine carrying high-pressure. The other expansion takes place in a different and independent turbine that is attached to the load. One can use more than two spools for the heating-up process. this is usually done with high-power aircraft machines.
This is the component without which the entire mechanism is shut down. Quite literally, if you do not know how to control the turbine, everything will fall apart. But the process is similar to controlling an electric generator. Doesn’t matter what the load is, the speed should be kept constant. If you want to decrease the load you will have to equate it with the fuel flow reduction. Then it will come to a balance. This may decrease the efficiency of the turbine, but the compressor will be unaffected which means that the amount of air remains the same.
Cooling and reheat systems
Cooling in gas turbines is done by NGV and blade cooling. It uses the general method of cooling, transpiration, and impinging film. It is done by aerodynamics mechanism. Reheating is just another part of gas turbines. It depends on the balance of temperatures, the time and length of burning, and the combustion efficiency.
Gas turbines are in existence for a long time. First, it started with steam engines and steam turbines. They turn water vapors into mechanical and then electrical energy. After the invention of gas turbines in 1947, the world saw a transformation in the power generating industry. It was then again developed and made more efficient in 2011. Ever since there have been many high and rising power plants. And it will keep developing with the latest technologies coming our way.