This set of Hydraulic Machines Assessment Questions and Answers focuses on “Constant Head Curves”.
1. Constant head curves are also called as _______
a) Head race curves
b) Tail race curves
c) Main characteristic curves
d) Impeller curves
View Answer
Explanation: Constant head curves are also called as main characteristic curves. It helps in determining the overall efficiency of the turbine by drawing curves with different set of parameters that play a major role in determining the performance of the turbine.
2. The speed of the turbine in a constant head curve is varied by __________
a) Temperature change
b) Reaction speed change
c) Changing the gate opening
d) Wheel speed change
View Answer
Explanation: The speed of the turbine in a constant head curve is varied by maintaining a constant head. When we maintain a constant head, the speed of the turbine is varied by regulating the flow of fluid through a sluice gate.
3. Constant speed curves travel at constant speed when the value is equal to _______
a) 0
b) 1
c) 2
d) 3
View Answer
Explanation: Constant speed curves detect the performance at different conditions. Characteristic curves of a turbine play an important role. It helps in determining the overall efficiency of the turbine by drawing curves with different set of parameters that play a major role in determining the performance of the turbine.
4. Power of a turbine is measured ______
a) Mechanically
b) Electrically
c) Chemically
d) Thermally
View Answer
Explanation: Power of a turbine is measured mechanically by adjusting the flow of fluid using the percentage variations in a sluice gate. It helps in determining the overall efficiency of the turbine.
5. Which among the following is not a parameter to determine the efficiency of the turbine?
a) Unit speed
b) Unit power
c) Unit volume
d) Unit discharge
View Answer
Explanation: Unit volume is not a parameter to determine the efficiency of the turbine. Power of a turbine is measured mechanically by adjusting the flow of fluid using the percentage variations in a sluice gate. It helps in determining the overall efficiency of the turbine.
6. Which among the following is not an important parameter to determine the performance of the turbine?
a) Speed
b) Discharge
c) Head
d) Volume of tank
View Answer
Explanation: Volume of tank is not an important parameter to determine the efficiency of the turbine. These are not drawn in the curves pertaining its efficiency.
7. Which among the following is not a type of curve?
a) Logarithimic curve
b) Straight curve
c) Pressure vs power
d) Efficiency vs speed
View Answer
Explanation: Pressure vs power is not a characteristic curve that determines the overall efficiency of the turbine. This relation does not exist.
8. The inlet passage of water entry is controlled by ________
a) Head race
b) Gate
c) Tail race
d) Pump
View Answer
Explanation: The inlet passage of water entry is controlled by the gate opening. The gate opening is an opening that sends only a percentage of fluid through the inlet passages for water to enter to the turbine.
9. Overall efficiency vs what is drawn to determine the turbine performance?
a) Unit Discharge
b) Unit speed
c) Unit power
d) Unit pressure
View Answer
Explanation: One of the graphs to determine the performance of the turbine is overall efficiency vs the unit speed of the turbine. Unit speed is a speed of the fluid flow from inlet to the outlet of the turbine.
10. Constant discharge takes place due to _______
a) Unit Discharge
b) Unit speed
c) Unit power
d) Unit pressure
View Answer
Explanation: Unit discharge is directly proportional to the discharge of fluid in the turbine. Unit discharge is the discharge through the turbine when the head of the turbine is unity. Unit discharge is one of the major unit quantities that determine the overall efficiency of the turbine.
11. All the characteristic curves are drawn with respect to __________
a) Unit Discharge
b) Unit speed
c) Unit power
d) Unit pressure
View Answer
Explanation: All the characteristic curves that specify different parameters in a turbine are drawn with respect to its unit speed. Unit discharge, unit power and overall efficiency vs the unit speed is drawn.
12. Constant head curves are also called as _______
a) Head race curves
b) Tail race curves
c) Main characteristic curves
d) Impeller curves
View Answer
Explanation: Constant head curves are also called as main characteristic curves. It helps in determining the overall efficiency of the turbine by drawing curves with different set of parameters that play a major role in determining the performance of the turbine.
13. In constant speed curves, the speed is kept a constant varying its head.
a) True
b) False
View Answer
Explanation: Constant speed curves are also called as operating characteristic curves. It helps in determining the overall efficiency of the turbine by drawing curves with different set of parameters that play a major role in determining the performance of the turbine.
14. In all the characteristic curves, the overall efficiency is aimed at the maximum value.
a) True
b) False
View Answer
Explanation: Yes, In all the characteristic curves, the overall efficiency is aimed at the maximum value. It helps in determining the overall efficiency of the turbine by drawing curves with different set of parameters that play a major role in determining the performance of the turbine.
15. Constant efficiency curves are plotted using _______
a) Constant head curves
b) Constant speed curves
c) Main characteristic curves
d) Constant speed and constant head
View Answer
Explanation: Constant efficiency curves are plotted using both Constant speed and constant head. Constant efficiency curves are also called as Muschel curves. It helps in determining the overall efficiency of the turbine by drawing curves with different set of parameters that play a major role in determining the performance of the turbine.
Sanfoundry Global Education & Learning Series – Hydraulic Machines.
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