Quiz 1 Examples Miscellaneous Questions Flashcards
list 3 different situations/factors that would create minor losses:
- an open valve
- expansions/contractions in pipe diameter
- pipe bends/elbows
EXTRA:
4. sudden stops (dead ends)
5. tees and junctions
6. rough welds
Centrifugal pumps can be designed…
… to be submersible (i.e. to allow installation in water wells)
What additional input data would you need to determine the pressure heads at junctions (using EPANET)? 2 things
- the elevations of the junctions
- the water surface elevation of reservoir A (starting reservoir)
Which one of the following applies to an arbitrary number (n) of pipes in series, and why:
a) ∑Qi = 0
b) Q = Q1 + Q2 + Q3 + … + Qn
c) Q = Q1 = Q2 = Q3 = … = Qn
d) hL1 = hL2 = hL3 = … = hLn
d) none of the above
C. for pipes in series, flow rate must be the same in each pipe b/c continuity applies (no junctions/branches therefore no loss/gain)
reasoning:
a) this applies to branching pipes with a common J (pipe networks)
b) this applies to pipes in parallel, where total flow spits among branches
d) also applies to pipes in parallel
The “Pump Problems” video discusses several issues that may occur with
centrifugal pumps. The figure below was used to illustrate one of these problems, which
results in no discharge from the pump (image with blue water on left, pump in the middle and pipe). The problem being illustrated is:
loss of prime
A parallel pipe system is shown below.
The system information is:
* pipe a : galvanized iron; D = 20.0 cm; L = 4.0 m
* pipe b : galvanized iron; D = 12.0 cm; L = 6.4 m
* water at 10°C
* open gate valve, Kv = 0.15; open globe valve, Kv = 10.0
* 90o elbow, Kml = 0.19
If the discharge through the system is to be simulated with EPANET2, using the DW equation, what value should be entered for “Loss Coeff.” in the menu for pipe b ? why?
a) 10.15
b) 10.0
c) 0.19
d) 10.53
e) none of the above
E
During fire flows (demands) the minimum pressure head required in municipal water
distribution systems is typically:
14 to 15m
What does the head-discharge graph for a centrifugal pump look like?
h (y axis), Q (x axis)
downward parabola
