Automotive Gas Turbine | Advantages and Disadvantages.

 

Gas turbine- 

A gas turbine essentially consists of two sections — a gasifier section and a power section. The fuel used in a gas turbine can be gasoline, kerosene, or oil. The gasifier section burns fuel in a burner and delivers the resulting gas to the power section, where it spins the power turbine. The power turbine then turns the vehicle wheels through a series of gears.

The gasifier consists of a compressor that has a rotor with a series of blades around its outer edge. As the rotor rotates, the air between the blades is carried around and thrown out by centrifugal force into the burner. Thus, air pressure rises in the burner. The fuel is injected into the burner where it burns and further rises the pressure. The high-pressure and high-temperature gas then passes through the gasifier nozzle diaphragm. A series of stationary blades directs this gas against a series of curved blades on the outer edge of the gasifier turbine rotor causing it to rotate at a high speed. This gasifier turbine rotor and the compressor rotor are mounted on the same shaft, thus the compressor rotor also rotates at high speed. The action continues to supply the burner with a sufficient amount of compressed air. The action continues as long as fuel is supplied to the burner.

After leaving the gasifier section, the high-pressure, high-temperature gas enters the power turbine. Here, it strikes another series of stationary curved blades which directs it against a series of curved blades on the outer edge of the power turbine rotor causing it to rotate at high speed, about 50,000 r.p.m. This high speed is reduced by a series of transmission gears before the power is supplied to the vehicle wheels.

Advantages of gas turbine- 

1. The gas turbine is smooth in operation and continuous in performance.
2. It does not have any reciprocating part, hence it is easy to balance. It is free from vibrations.
3. There is no sequence of suction, compression, ignition, and expansion, as in the petrol engine.
4. Once the spray has been ignited by an electric spark, combustion is continuous and no further ignition is necessary.
5. Flywheel is not required because the turbine exerts a smooth and continuous torque on the shaft.
6. It has higher mechanical efficiency.
7. It is compact in shape, simple in design, and light in weight.
8. Although the initial cost is high, the maintenance cost is low.
9. It can use cheaper fuels.
10. Oil consumption is low.
11. It has low internal friction and resistance.
12. There is no need for clutches and a gearbox in it except for reversing.

Disadvantages of gas turbine- 

1. The gas turbine, in its simplest form, consumes 70% more fuel than a petrol engine for the same power. 
2. Due to the very high speed, the gas turbine causes serious problems in obtaining an effective transmission speed suitable for road speeds. 
3. Breaking is also not affecting due to very high speed. The average turbine speed varies from 25,000 to 50,000 r.p.m. 
4. A serious objection to the use of gas turbines on-road vehicles is a large number of exhaust fumes, a nuisance, and hazards on the road in heavy traffic.