Turbo machines imp notes

Turbo machines imp notes

  

1)   Work input factor & Work done factor is the proportion of the actual work absorbed by an axial flow compressor to the theoretical work.

2)   Degree of reaction can be well-defined as the ratio of the pressure rise in rotor blades to the pressure rise in stages in an axial flow compressor.

3)   Pressure coefficient is the ratio of isentropic work to Euler work in a centrifugal compressor.

4)   The ratio of actual whirl velocity to the ideal whirl velocity in the centrifugal compressor is called as slip factor.

5)   Vaneless diffusers are suitable for only low-pressure rise.

6)   Angular momentum of gas in the free vortex of vaneless diffuser remains constant.

7)   Axial flow centrifugal pumps have higher specific speed than the others.

8)   The volute pumps and vortex volute pumps are

single stage pumps with horizontal shaft.

9)   The process of filling the liquid into the suction pipe and pump casing up to the level of delivery valve is called priming.

10)   Reciprocating pump is more suitable for an application where very high pressure is required to be developed at moderate discharge.

11)   Discharge capacity of the reciprocating pump is lower than that of the centrifugal pump.

12)   The blade speed ratio of impulse turbine is given as  Blade velocity / Steam velocity at inlet.

17)  Steam turbine is a rotary high-speed machine

And has low weight to power ratio.

18)   The ratio of actual mass flow rate to ideal mass flow rate that is called as coefficient of discharge.

21)   In reaction turbine work is done mostly due to change in pressure head and small amount of work is due to change in kinetic energy.

22)   In Reaction turbine, the runner needs to be run full of water.

23)   As the reaction turbine works on the principle of impulse and reaction, it follows the law of angular momentum.

24)   Draft tube is the components of reaction turbine increases the head on the turbine by an amount equal to the height of runner outlet above the tail race.

25)   The gates of aero foil section in between the outer and inner ring of guide wheel are called as

guide vanes.

26)   What is the formula for the velocity of water jet at the inlet of turbine?

Where,

H = Net head acting on Pelton wheel

C_v= coefficient of velocity of jet

V = Cv √2gH.

27)   What is runaway speed of the runner of Pelton wheel?

maximum unsafe speed of the runner due to sudden decrease in load on turbine.

28)   Gross head is the difference between

head race and tail race.

29)   What is the head of water available at turbine inlet in hydro-electric power plant called net head.

30)  Tangential of fluid velocity is responsible for transmission of power through rotodynamic machine.

31)   The blade passages in a compressor are

Diverging passages.

32)   The basic principle of operation of axial flow compressor is same as that of the centrifugal compressor.

33)   Moving blades are attached to the

rotor or spindle.

34)   An axial flow compressor has

a drum type rotor or a disc type rotor.

35)   A pair of fixed blade and rotor blade in axial flow compressor is called as Stage.

36) Air velocity increases in impeller and decreases in Diffuser.

37)   The function of diffuser is to convert high kinetic energy of gases into pressure energy.

38)   The mass flow rate of air compressed in axial flow compressor is higher than centrifugal compressor.

39) Centrifugal pump is also called as velocity pump.

40)   Gear pump, Vane pump, & Rotary piston pump example of rotary displacement pumps.   This pump is suitable for handling oils.

41)   Pump transfers the mechanical energy of a motor or of an engine into pressure energy & kinetic energy.

42)   The quality of vapour at the exit of nozzle

increases due to nozzle friction.

43)   effects of nozzle friction are

Enthalpy drop decreases, Exit velocity reduces, Decrease in mass flow rate.

44)   The nozzle efficiency can be defined as the ratio of actual enthalpy drops to isentropic enthalpy drop.

45)   The passage of uniformly varying cross-section in which the kinetic energy of steam increases at the expense of its pressure is called as steam nozzle.

46)   Generally, the value of specific speed of Kaplan turbine is higher than that of the Pelton turbine.

 For Download PDF Click Here