Question

4. A large reservoir discharging water is shown in Figure 3. Table 1 shows the relevant characteristics of pipe sections A and B. A solenoid valve is also used to control the flow of water from pipe section A to B in case of emergency shut-off operations. Assuming all minor flow loss factors associated with any water entry and exit from the reservoir/valve are $k = 0.5$ throughout, and that the valve is fully opened, determine Table 1 Section A Section B Pipe length ($L$) 400m 300m Pipe diameter ($D$) 50cm 20cm Darcy friction factor ($f$) 0.02 0.01 Large reservoir Pipe section A Pipe section B C 100m Valve Figure 3 60m (a) Starting with the Bernoulli's equation, the steady-state velocity of the discharged water, (9 marks) (b) the maximum water hammer pressure at the valve if the valve were to be fully closed abruptly during an emergency and that pressure wave velocity is 800 m/s, (3 marks) (c) the expression that describes the rate of change in flow velocity in pipe section A, $\frac{\partial V_A}{\partial t}$, as a function of that flow velocity, $V_A$, if the valve is opened abruptly again, and (4 marks) (d) plot and compare the pressure-time graphs of the pressures associated with the water hammer scenario in Part (c) at the valve location, and a location located at 100m away from the reservoir exit shown as point C. Indicate on the graphs, the water hammer pressure and timings, as well as the time interval between the times when the valve and point C first experience water hammer pressure. (6 marks) (e) What can be used to mitigate the effects of water hammer behaviour and where should it be located? Explain how it works. (3 marks)

          4.
A large reservoir discharging water is shown in Figure 3. Table 1 shows the relevant
characteristics of pipe sections A and B. A solenoid valve is also used to control the
flow of water from pipe section A to B in case of emergency shut-off operations.
Assuming all minor flow loss factors associated with any water entry and exit from the
reservoir/valve are $k = 0.5$ throughout, and that the valve is fully opened, determine
Table 1
Section A	Section B
Pipe length ($L$)	400m	300m
Pipe diameter ($D$)	50cm	20cm
Darcy friction factor ($f$)	0.02	0.01
Large reservoir
Pipe section A	Pipe section B
C
100m
Valve
Figure 3
60m
(a) Starting with the Bernoulli's equation, the steady-state velocity of the discharged water,
(9 marks)
(b) the maximum water hammer pressure at the valve if the valve were to be fully closed
abruptly during an emergency and that pressure wave velocity is 800 m/s,
(3 marks)
(c) the expression that describes the rate of change in flow velocity in pipe section A, $\frac{\partial V_A}{\partial t}$,
as a function of that flow velocity, $V_A$, if the valve is opened abruptly again, and
(4 marks)
(d) plot and compare the pressure-time graphs of the pressures associated with the water
hammer scenario in Part (c) at the valve location, and a location located at 100m away
from the reservoir exit shown as point C. Indicate on the graphs, the water hammer
pressure and timings, as well as the time interval between the times when the valve and
point C first experience water hammer pressure.
(6 marks)
(e) What can be used to mitigate the effects of water hammer behaviour and where should
it be located? Explain how it works.
(3 marks)

4.
A large reservoir discharging water is shown in Figure 3. Table 1 shows the relevant
characteristics of pipe sections A and B. A solenoid valve is also used to control the
flow of water from pipe section A to B in case of emergency shut-off operations.
Assuming all minor flow loss factors associated with any water entry and exit from the
reservoir/valve are k = 0.5 throughout, and that the valve is fully opened, determine
Table 1
Section A Section B
Pipe length (L) 400m 300m
Pipe diameter (D) 50cm 20cm
Darcy friction factor (f) 0.02 0.01
Large reservoir
Pipe section A Pipe section B
C
100m
Valve
Figure 3
60m
(a) Starting with the Bernoulli's equation, the steady-state velocity of the discharged water,
(9 marks)
(b) the maximum water hammer pressure at the valve if the valve were to be fully closed
abruptly during an emergency and that pressure wave velocity is 800 m/s,
(3 marks)
(c) the expression that describes the rate of change in flow velocity in pipe section A, (∂ VA)/(∂ t),
as a function of that flow velocity, VA, if the valve is opened abruptly again, and
(4 marks)
(d) plot and compare the pressure-time graphs of the pressures associated with the water
hammer scenario in Part (c) at the valve location, and a location located at 100m away
from the reservoir exit shown as point C. Indicate on the graphs, the water hammer
pressure and timings, as well as the time interval between the times when the valve and
point C first experience water hammer pressure.
(6 marks)
(e) What can be used to mitigate the effects of water hammer behaviour and where should
it be located? Explain how it works.
(3 marks)

Added by Joshua M.

Question

Please give Ace some feedback