Important Questions and Answers: Diesel and Gas Turbine Power Plant

DIESEL AND GAS TURBINE POWER PLANT

1. What is the essential component of diesel power plants?

Essential components of a diesel power plant are:

(i) Engine                    (ii)Air intake system

(iii)Exhaust system       (iv)Fuel system

(v) Cooling system       (vi) Lubrication system

(vii)Engine starting system  (viii) Governing system.

2. List the various Liquid Cooling Systems?

In liquid cooling following methods are used for circulating the water around the cylinder and cylinder head:

(i) Thermo-system cooling

(ii) Forced or pump cooling

(iii) Cooling with thermostatic regulator

(iv)       Pressurized cooling

(v)Evaporative cooling.

3. What is the purpose of super charging?

The purpose of supercharging is to raise the volumetric efficiency above that value which can be obtained by normal aspiration.

4. Define Flywheel?

It is a heavy wheel mounted on the crankshaft. It stores the excess energy delivered by the engine during power stroke and supplies the energy needed during other strokes. Thus it keeps the fluctuations in the crankshaft speed within desired limits.

5. Write the Disadvantages of over cooling of the Engine?

1) Engine starting is difficult,

2) Over-cooling reduces the overall efficiency of the system,

3) At low temperatures, corrosion assumes considerable magnitude that it may reduce the life of various components.

6. Write the function of Lubrication?

a.    To  reduce  the  wear  and  tear  between  the  moving  parts  and  thereby

increasing the life of the engine.

b. The lubricating oil acts as a seal, i.e., it prevents the high pressure gases in thecombustion chamber from entering the crankcase

c.      To cool the surfaces.

7. What are the classifications of Lubrication system? Classification of Lubrication System:

Some of the lubricating systems used for IC engines are:

i)                   Wet sump lubricating system,

ii)                ii) Mist lubricating system.

Wet sump lubricating system can be further classified as,

i) Splash type lubricating system,

ii) Pressure feed lubricating system.

8. Define – open cycle gas turbine?

In the open cycle gas turbine, air is drawn into the compressor from atmosphere and is compressed. The compressed air is heated by directly burning the fuel in the air at constant pressure in the combustion chamber. Then the high pressure hot gases expand in the turbine and mechanical power is developed.

9. Define – closed cycle gas turbine?

In this, the compressed air from the compressor is heated in a heat exchange (air heater) by some external source of heat (coal or oil) at constant pressure. Then the high pressure hot gases expand passing through the turbine and mechanical power is developed. The exhaust gas is then cooled to its original temperature in a cooler before passing into the compressor again.

10. Write the few fuels for Gas turbine and why these fuels are use for gas turbine?

Natural gas, last furnace gas, produce gas, coal gas and solid fuels distillate oils and residual oils paraffins used in gas turbine and methane, ethane, propane, octane.

Important properties to be considered while selecting the fuel for gas turbine are as follows:

1) Volatility 2) Combustion products,

3) Energy contents, 4) Lubricating properties, 5) Availability.

11.        Write the major field of application of gas turbines?

The major fields of application of gas turbines are:

i)  Aviation

ii) Power generation

iii) Oil and gas industry

iv)Marine propulsion.

12.        Define Gas turbine plant and write the working medium of this gas turbine?

A gas turbine plant may be defined as one “in which the principal prime-mover is of the turbine type and the working medium is a permanent gas”.

13. What are the components of gas turbine plant?

A simple gas turbine plant consists of the following:

i) Turbine ii) Compressor iii) Combustor iv) Auxiliaries

.A modified plant may have in   addition and intercooler, a regenerator, a repeater etc.

14. What are the methods to improving the thermal efficiency in open cycle gas turbine

plant?

Methods for improvement of thermal efficiency of open cycle gas turbine plant are :

i)                  Inter cooling

ii)                Reheating

iii)             Regeneration

15. Define turbo charging in combined gas turbine and diesel cycles?

In the combined cycle, the exhaust gas from the diesel engine is expanded in the turbine, which is coupled with compressor which supplies pressurized air to the diesel engine. This increases diesel engine output. This arrangement is known as turbo charging.