Francis turbine is
- Aan impulse turbine
- Ba radial flow impulse turbine
- Can axial flow turbine
- Da reaction radial flow turbineCorrect
Solution
Concept
Classification of Francis turbine
Formula
NONE
Step-by-step solution
1. Turbines are classified based on the direction of fluid flow through the runner and the type of energy conversion. 2. Francis turbine operates under pressure energy where water enters radially inward and leaves axially. 3. Therefore, Francis turbine is classified as a reaction radial flow turbine. Answer: D
Explanation
A Francis turbine operates under fluid pressure where water enters the runner in a radial direction and moves inward toward the discharge. Because the energy conversion occurs due to both pressure and velocity changes within the enclosed runner, it is classified as a reaction turbine with radial flow.
Why the other options are wrong
A) Francis turbine operates primarily on reaction rather than impulse force. B) Francis turbine is a reaction turbine rather than an impulse turbine. C) Francis turbine is a mixed/radial flow turbine, whereas Kaplan turbine is an axial flow turbine.
Shortcut
Francis turbine = Radial flow reaction turbine ("FR" = Francis Radial).
Common mistake
Confusing the Francis turbine (reaction radial flow) with Pelton wheel (impulse) or Kaplan turbine (axial flow).
Correct answer: D) a reaction radial flow turbine