Francis Turbine topics include: Francis turbine velocity diagrams, francis turbine work and efficiency. A Francis turbine is a type of reaction turbine invented by James B. Francis around 1855. It is the most common type of turbine used today. Francis turbines are used in about 60% of the world's hydropower capacity.  Here's how a Francis turbine works: Water enters the turbine in a radial direction, flowing towards its axis. The water is deflected 90 degrees in the runner, which sets the runner and the generator in a rotary motion. The energy released in this way can achieve an... Show more

Francis Turbine topics include: Francis turbine velocity diagrams, francis turbine work and efficiency.

A Francis turbine is a type of reaction turbine invented by James B. Francis around 1855. It is the most common type of turbine used today. Francis turbines are used in about 60% of the world's hydropower capacity. 

Here's how a Francis turbine works:
Water enters the turbine in a radial direction, flowing towards its axis.
The water is deflected 90 degrees in the runner, which sets the runner and the generator in a rotary motion.
The energy released in this way can achieve an efficiency of up to 95%. 

Here are some other features of Francis turbines:
They have a radial flow runner with fixed buckets, usually nine or more.
The turbine must be completely immersed when in operation.
The wicket gate around the outside of the turbines rotating runner controls the rate of water flow through the turbine for different power production rates.
The turbine runner is connected to an electrical generator by a common shaft.
As the runner rotates, so does the generator rotor.
The rotor rotates through an electromagnetic field, which induces current in the stator windings.

Show less

Hydraulic Machines Practice Test: Francis Turbine

Time left 00:00

25 Questions

1. Which of the following terms is considered to be zero while deriving the equation for work done per second for Francis Turbine?

Vf2Vw2Vr1Vr2

2. The whirl velocity at inlet is 15 m/s and blade velocity is 10 m/s. The volume flow rate of water in 20 m³/s. Find the power output available at the shaft if the mechanical efficiency is 95% (in MW)?

2.856.553.0750.285

3. Which of the following efficiencies for Francis Turbine is defined as the ratio between the power available at the shaft of the turbine to the power produced by the runner?

Volumetric efficiencyOverall efficiencyMechanical efficiencyHydraulic efficiency

4. What is the water flow direction in the runner in a Francis turbine?

Axial and then radialTangential and then axialAxial and then tangentialRadial and then axial

5. Water flow velocity is given 10 m/s. The runner diameter is 3 m and the width of the wheel is 25 cm. Find the mass of water (kg) flowing across the runner per second.

7500πRPM of the turbine needs to be given300π50π

6. The power output of the shaft is 5 MW. The volume flow rate of water in 10 m³/s at an available head of 60 m. Find the overall efficiency of the turbine in % (g = 10 m/s²)?

83.38582.580

7. In the figure shown below,which of the following angles replace the question mark?

Blade angle at inletVane angle at inletBlade angle at outletGuide vane angle at inlet

8. In which of the following type of runners the velocity of whirl at inlet is greater than the blade velocity?

Fast RunnerSlow RunnerSuch a case is practically impossibleMedium Runner

9. The volumetric efficiency of a Francis turbine is given to be 90%. If the volume flow rate through the turbine is 25 m³/s. What is the flow rate of water over the runner blades (in m³/s)?

21.52522.520

10. Francis turbine is typically used for which of the following values of available heads?

300 m5 m30 m100 m

11. Velocity of whirl at the runner inlet is given to be 10 m/s and blade velocity to be 5 m/s. The volume flow rate of water in Francis turbine is given to be 25 m³/s. Find the power generated by the turbine?

1000 HP800 HP3400 HP1700 HP

12. The whirl velocity at inlet of Francis turbine is given to be 20 m/s. The blade velocity is given as 35 m/s. What is the hydraulic efficiency for a head of 100 m?

80%90%98%70%

13. The volumetric efficiency of a given turbine is 80%. If volume flow rate of water in given to be 30 m³/s, find the volume of water (m³) NOT flowing over the runner blades per second?

121065

14. In the figure shown below, which of the following type of runners has the blade curvature as shown in the above figure (The arrow denotes direction of blade motion)?

Fast RunnerSlow RunnerMedium RunnerInformation insufficient to determine

15. The input water power of the Francis turbine is 1.25 times the runner power. What would be the hydraulic efficiency of the turbine (in %)?

70609080

16. The volume flow rate of water in 10 m³/s at an available head of 60 m (g = 10 m/s³). Find the shaft power (in MW) if the overall efficiency of the turbine is 90%.

5.40.5454054

17. Which of the following runner types will have the highest vane angle at inlet (β1 value)?

Slow RunnerFast RunnerVane angle is defined only for Kaplan Turbines and not Francis turbinesMedium Runner

18. The hydraulic efficiency of a Francis turbine is 90%, the mechanical efficiency is 95% and the volumetric efficiency is assumed to be 100%. Fine the overall efficiency (in %)?

85.583.38087.5

19. What is the typical value for flow ratio in a Francis turbine?

0.15 – 0.300.05 – 0.10.50 – 0.600.35 – 0.45

20. Which of the following efficiencies for Francis Turbine is defined as the ratio between the power available at the shaft to the power supplied by water at the inlet?

Mechanical efficiencyOverall efficiencyVolumetric efficiencyHydraulic efficiency

21. The flow rate of the water flow in a Francis turbine is increased by 50% keeping all the other parameters same. The work done by the turbine changes by?

25% increase100% increase50% increase150% increase

22. Which of the following profiles are used for guide vanes to ensure smooth flow without separation?

RectangularEllipticalBent RectangularAerofoil

23. The available head of a Francis Turbine is 100 m. Velocity of the flow at the runner inlet is 15 m/s. Find the flow ratio.

0.890.670.330.45

24. Work done per second by a Francis turbine can be given by ρAVf (Vw1u1 + Vw2u2).

TrueFalseDon't KnowMaybe

25. A student performs an experiment with a Francis turbine. He accidently set the RPM of Francis turbine to 1400 rpm instead of 700 rpm. He reported the power to be 1 MW. His teacher asks him to perform the same experiment using the correct RPM. The student performs the same experiment again, but this time the erroneously doubled the flow velocity. What does the student report the power to be?

1 MW2 MW0.25 MW0.5 MW