STEAM TURBINES

The pressure compounded impulse turbine as compared to velocity compounded turbine require __________ number of stages.

• Same

• Less

• More

• None of these

In an impulse turbine.......

• The steam is expanded in nozzles only and there is a pressure drop and heat drop

• The steam is expanded both in fixed and moving blades continuously

• The steam is expanded in moving blades only

• The pressure and temperature of steam remains constant

The person's reaction turbine has........

• Only moving blades

• Only fixed blades

• Identical moving and fixed blades

• Fixed and moving blades of different shape

The stage efficiency (ηs)is given by ( where ηb=blading efficiency and ηn =nozzle efficiency )........

• ηb/ηn

• ηn/ηb

• ηb.ηn

• ηn/ηb

The reheating of steam in a turbine........

• Increases the work done through the turbine

• Increases the efficiency of the turbine

• Reduces wear on the blades

• All of the above

The thermal efficiency of a steam turbine is......than that of steam engine

• Lower

• Higher

• Same

• None of the above

Da-laval turbines are mostly used.......

• Where low speeds are required

• For small power purposes and and low speeds

• For small power purposes and and high speeds

• For large power purposes

The degree of reaction is defined as the ratio........

• Heat drop in the fixed blades to the heat drop in the moving blades

• Heat drop in the moving blades to the heat drop in the fixed blades

• Heat drop in the moving blades to the total heat drop in the fixed blades

• Heat drop in the fixed blades to the total heat drop in the moving blades

The maximum efficiency of a Da-Lavel turbine is (where α= nozzle angle)........

• Sin^2α

• Cos^2 α

• Tan^2 α

• Cot^2 α

The ratio of isentropic heat drop to the heat supplied is called........

• Rankine efficiency

• Stage efficiency

• Reheat factor

• Internal efficiency