The ratio of outlet whirl velocity to blade velocity in case of centrifugal compressor is called__________________?

Related Mcqs:

1. If V, U and Vr represent the absolute velocity of fluid, velocity of blade, and relative velocity of fluid, and suffix i and o stand for entry and exit conditions, then in a rotary machine whose degree of reaction is unity______________?

   A. Vi=V0B
   B. Vt>V0
   C. U,<V0
   D. V,= U0
   E. Vri=Vm

2. The degree of reaction of an axial flow turbine is the ratio of isentropic temperature drop in a blade row to the_____________________?

   A. adiabatic temperature drop in the stage
   B. total temperature drop
   C. total temperature drop in the stage
   D. total adiabaitc temperature drop
   E. difference of maximum and minimum temperature in the cycle

3. The ratio of work doen per cycle to the swept volume in case of compressor is called ______________?

   A. compression index
   B. compression ratio
   C. compressor efficiency
   D. mean effective pressure
   E. compressor effectiveness

4. A centrifugal compressor works on the principle of__________________?

   A. conversion of pressure energy into kinetic energy
   B. conversion of kinetic energy into pres¬sure energy
   C. centripetal action
   D. generating pressure directly
   E. combination of A. and D.

5. The thrust on the rotor in a centrifugal compressor is produced by________________?

   A. radial component
   B. axial component
   C. tangential component
   D. resultant component

6. Losses in a centrifugal compressor are due to__________________?

   A. inlet losses
   B. impeller channel losses
   C. diffuser losses
   D. all of the above
   E. none of the above

7. Axial flow compressor has the following advantage over centrifugal compressor__________________?

   A. larger air handling ability per unit frontal area
   B. higher pressure ratio per stage
   C. aerofoil blades are used
   D. higher average velocities
   E. none of the above

8. For a two stage compressor* if index of compression for higher stage is greater than index of compression for lower stage, then the optimum pressure as compared to ideal case will___________________?

   A. increase
   B. decrease
   C. remain unaffected
   D. other factors control it
   E. unpredictable

9. The pressure ratio of an ideal vaned compressor with increase in mass flow rate_________________?

   A. increases
   B. decreases
   C. remains constant
   D. first decreases and then increases
   E. unpredictable

10. The specific output per kg mass flow rate of a gas turbine (having fixed efficiencies of compressor and turine and fixed higher and lower temperature) with increase in pressure ratio will___________________?

    A. increase first at fast rate and then slow
    B. increase first at slow rate and then fast
    C. decrease continuously
    D. first increase, reach maximum and then decrease
    E. none of the above