PURPOSE OF EXPERIMENT:
The purpose of the lab is to demonstrate how the velocity profile in a flow can be
measured and used to determine the volumetric discharge using a Stagnation Tube Rake,
Venture Meter, and Hastings Meter.
(1)
Stagnation Tube Rake
: Using the stagnation tube rake we record the initial static
pressure as well as the moving pressure at 40, 75, and 110 volts. We were also to
determine the difference in pressure, the local velocities using Bernoulli’s
equation, plot and discuss the velocity distribution, find the mean volumetric
flow, the mean velocity of flow for the cross sectional area V=Q/A, determine
which stagnation tube best measures the mean velocity, repeat above for second
and third flow rates, Q, and note the shape observed from the stagnation tube
rake.
(2)
Venturi Meter
: record the static pressure at the 2 points, calculate the height
difference, and determine the flow rate in L/s and m3/s.
(3)
Hasings Meter
: Take readings for two flow rates, Q, in m3/min and m3/s and
calculate K=Q(venture)/Q(hastings).
Procedure:
(1)
Stagnation Tube Rake
: Using the stagnation tube rake we record the initial static
pressure as well as the moving pressure. We were also to determine the difference
in pressure, the local velocities using Bernoulli’s equation, plot and discuss the
velocity distribution, find the mean volumetric flow, the mean velocity of flow for
the cross sectional area V=Q/A, determine which stagnation tube best measures
the mean velocity, repeat above for second and third flow rates, Q, and note the
shape observed from the stagnation tube rake. Equations needed are:
V=Q/A
U=√(2*g*h*(specific weight of water/specific weight of air))
Specific weight of water = 9732 N/m3
Specific weight of air = 11.08 N/m3
(Both specific weights are at 40 degrees C taken from the table in the back of the
fluids book)
(2)
Venturi Meter
: record the static pressure at the 2 points, calculate the height
difference, and determine the flow rate in L/s and m3/s.
(3)
Hasings Meter
: Take readings for two flow rates, Q, in m3/min and m3/s and
calculate K=Q(venture)/Q(hastings).