Hydraulic Machines test on “Inward Radial Flow Reaction Turbines”.
1. Inward radial flow reaction turbine is a turbine in which water flows across the blades of runner______________
a) Radial direction
b) Radially inward
c) Radially outward
d) Axial direction
Answer: b
Clarification: The name itself indicates that flow is in radial direction and flowing from outer periphery towards center.
2. Which of following is inward radial flow reaction turbine?
a) Pelton wheel
b) Francis turbine
c) Axial turbine
d) Kaplan turbine
Answer: b
Clarification: Pelton is impulse a turbine, Kaplan is axial flow turbine and Francis is an inward flow reaction turbine.
3. In Inward radial flow reaction turbine which is not required?
a) Runner
b) Air tight casing
c) Guide vanes
d) Breaking jet
Answer: d
Clarification: Here in inward flow reaction turbine, instead of jet water is passed into spiral casing directly and breaking jet is not used for its halt instead of it guide vanes are used.
4. The main difference between reaction turbine and inward radial flow reaction turbine is water flows___________
a) Radial direction
b) Radially inward
c) Radially outward
d) Axial direction
Answer: b
Clarification: The name itself indicates the type of flow that is radial direction but the thing that is unknown is whether it is radially inward or outwards.
5. In Inward radial flow reaction turbine the ratio of tangential wheel at inlet to given velocity of jet is known as _______
a) Speed ratio
b) Flow ratio
c) Discharge
d) Radial discharge
Answer: b
Clarification: Flow ratio is known as ratio of tangential wheel at inlet to given velocity of jet and it is scalar quantity.
6. In Inward radial flow reaction turbine the ratio of tangential velocity at inlet to the given velocity ____________
a) Speed ratio
b) Flow ratio
c) Discharge
d) Radial discharge
Answer: a
Clarification: Speed ratio is ratio of tangential velocity at inlet to the given velocity and it is scalar quantity because it is ratio of two speeds.
7. The discharge through a reaction radial flow turbine is given by____________
a) P1*b1*Vf1
b) P2*b2*Vf2
c) P1*b2*Vf2
d) Both a & b
Where, P1= perimeter of runner at inlet, P2= perimeter of runner at outlet, b= thickness and V f= flow velocity
Answer: d
Clarification: Discharge of radial flow reaction turbine is product of perimeter of runner, thickness, whirl velocity, at inlet as well as outlet runner vanes.
8. In Inward radial flow reaction turbine if thickness is considered then discharge is _________
a) (P1-n*t)*b1*Vf1
b) (P2-n*t)*b2*Vf2
c) (P1-n*t)*b2*Vf2
d) Both a & b
Where, P1= perimeter of runner at inlet, P2= perimeter of runner at outlet, b= width, Vf= flow velocity, n= number of blades and t= thickness of blades
Answer: d
Clarification: Discharge of radial flow reaction turbine is product of perimeter of runner, thickness, whirl velocity, at inlet as well as outlet runner vanes. If n blades of thickness t is considered then discharge is (P1-n*t)*b1*Vf1.
9. In Inward radial flow reaction turbine if angle made by absolute velocity with its tangent is 90 degrees and component of whirl is zero at outlet is _____________
a) Radial inlet discharge
b) Radial outlet discharge
c) Flow ratio
d) Speed ratio