Hydraulic Machines Questions and Answers for Experienced people on “Governing of Turbines – 2”.
1. In nozzle governing, the flow rate of steam is regulated by _________
a) Nozzles
b) Pumping
c) Drafting
d) Intercooling
Answer: a
Clarification: The process of controlling the flow rate of a substance is called as governing. It is done by maintaining the speed of rotation at a constant rate. In nozzle governing, the flow rate of steam is regulated by nozzles.
2. The flow rate of steam is controlled by regulating the_________
a) Steam
b) Pressure
c) Temperature
d) Speed
Answer: b
Clarification: The process of controlling the flow rate is called as governing. It is done to maintain its speed at a constant rate during rotation of the turbine rotor. The flow rate of steam is controlled by regulating the pressure.
3. The main function of nozzle is to __________
a) Varying temperatures
b) Pressure variations
c) Load variations
d) Heat variations
Answer: b
Clarification: The main function of nozzle is to vary the pressure of fluid passing through the nozzle. It is done by opening and shutting the sets of nozzles. Thus, its main function is to regulate pressure of the fluid.
4. What is primary objective of steam turbine governing?
a) Maintain constant speed
b) Maintain constant pressure
c) Maintain constant temperature
d) Maintain constant expansion
Answer: a
Clarification: The primary objective of steam turbine governing is to maintain a constant speed at varying loads. That means, irrespective of the load that is developed in the turbine, the speed remains a constant.
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
Answer: c
Clarification: 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 control the flow rate?
a) Valve
b) Pump
c) Head
d) Tank pipe
Answer: a
Clarification: Flow rate of the tank is controlled by the valve. The actuation of individual valve closes. This corresponds to the set of nozzle thereby controlling the actual flow rate of the fluid passing through the valve.
7. The advantage of nozzle governing is that no regulating pressure is applied.
a) True
b) False
Answer: a
Clarification: The advantage of nozzle governing is that no regulating pressure is applied. The actuation of individual valve closes the corresponding set of nozzle. Thus, controlling the flow rate.
8. The inlet passage of water entry is controlled by ________
a) Head race
b) Gate
c) Tail race
d) Pump
Answer: b
Clarification: 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. When do we apply by pass governing?
a) When turbine is overloaded
b) When Unit speed decreases
c) When Unit power increases
d) When Unit pressure decreases
Answer: a
Clarification: The main purpose of by pass governing is taken into full action when the turbine is overloaded for short durations. This happens occasionally in the working of the turbine. During this, a bypass valve is used.
10. When bypass valve is opened to _______
a) Increase Pressure
b) Increase Unit speed
c) Increase Unit power
d) Increase the amount of fresh steam
Answer: d
Clarification: When a by pass valve is opened, a fresh steam is introduced into the turbine, thereby increasing the amount of fresh steam. The main purpose of by pass governing is taken into full action when the turbine is overloaded for short durations.
11. What is the unit of steam rate?
a) kg
b) kg/m
c) kg/kWh
d) N/m
Answer: c
Clarification: The unit of stream is equal to kg/kWh. In the process of throttle governing, it is denoted by the symbol ‘a’. The variation of the steam consumption rate with the turbine load during governing is linear.
12. With the increase in load, Energy in the turbine ________
a) Decreases
b) Increases
c) Remains same
d) Independent
Answer: a
Clarification: When there is an increase in the load, the energy in the turbine is drained off. Thus, to increase the energy, the by pass valve is opened to increase the amount of fresh steam entry. This increases the energy in the turbine.
13. Combination governing involves usage of two or more governing.
a) True
b) False
Answer: a
Clarification: Yes, Combination governing involves usage of two or more governing. Most usage is the by pass and the nozzle governing as they tend to match the load on the turbine. Thus, increasing its efficiency.
14. When the mechanical speed of the shaft increases beyond 110 percent, we use _________
a) Throttle governing
b) Steam governing
c) Nozzle governing
d) Emergency governing
Answer: d
Clarification: When the mechanical speed of the shaft increases beyond 110 percent, we use emergency governing. These governors come into action only when there are emergencies in the turbine.
15. When the balancing of the turbine is disturbed, we use ________
a) Throttle governing
b) Steam governing
c) Nozzle governing
d) Emergency governing
Answer: d
Clarification: When the balancing of the turbine is disturbed, we use emergency governing. These governors come into action only when there are emergencies in the turbine.
Hydraulic Machines for Experienced people,