Title
of Experiment: Impact Of Fluid Jet
Course
No: MEHB331
Section:
***
Day
Experiment performed: 99
Lecturer:*****
Purpose/
Objectives.
The
objective of the experiment is to investigate the rate of momentum produced by
the striking of water jet on plates with different geometrical shape.
Data/
Observation and Results.
Diameter
of nozzle(D)=0.01m
Cross-sectional
area of nozzle(A)=pD2/4=7.85*10-5
m2
Mass
of jockey weight(m)=0.6kg
Distance
from center of vane to pivot of lever(d)=0.15m
Density
of water(r)=1000kg/m3
S=height
of vane above tip of nozzle
=0.035m
g=9.81m/s2
For
Flat Plate
|
Weight
of water collected (kg) |
V (m3) |
Time (s) |
Distance
of jockey from zero position (y) |
M(kg/s) |
U(m/s) |
U0(m/s) |
MU0(N) |
F(N) |
|
15 |
0.015 |
108.75 |
0.0125 |
0.138 |
1.758 |
1.550 |
0.2139 |
0.2139 |
|
15 |
0.015 |
82.19 |
0.024 |
0.183 |
2.331 |
2.179 |
0.3988 |
0.3988 |
|
5 |
0.005 |
36.37 |
0.030 |
0.137 |
1.745 |
1.536 |
0.2104 |
0.2104 |
|
5 |
0.005 |
29.41 |
0.045 |
0.170 |
2.166 |
2.001 |
0.3402 |
0.3402 |
|
5 |
0.005 |
27.5 |
0.053 |
0.182 |
2.318 |
2.165 |
0.3940 |
0.3940 |
|
5 |
0.005 |
25.47 |
0.060 |
0.196 |
2.497 |
2.355 |
0.4616 |
0.4616 |
|
5 |
0.005 |
22.91 |
0.0788 |
0.218 |
2.777 |
2.650 |
0.5777 |
0.5777 |
Weight
of water collected=r*V(kg)
M=weight
of water collected/Time(kg/s)
U0=(U2-2gs)1/2
U=M/rA
F=MU0
Sample
calculation:
Weight
of water collected=r*V
=1000*0.015
=15kg
M=15kg/108.75s=0.138kg/s
For
Conical Plate.
|
Weight of water
collected (kg) |
V (m3) |
Time (s) |
Distance of
jockey from zero position (y) |
M(kg/s) |
U(m/s) |
U0(m/s) |
MU0(N) |
F(N) |
|
5 |
0.005 |
55.25 |
0.0209 |
0.0905 |
1.153 |
0.8017 |
0.0726 |
0.1089 |
|
5 |
0.005 |
38.35 |
0.0435 |
0.1300 |
1.656 |
1.4377 |
0.1864 |
0.2796 |
|
5 |
0.005 |
31.16 |
0.0675 |
0.1600 |
2.038 |
1.8619 |
0.2979 |
0.4469 |
|
5 |
0.005 |
28.16 |
0.0835 |
0.1780 |
2.268 |
2.1112 |
0.3758 |
0.5637 |
|
5 |
0.005 |
25.60 |
0.0945 |
0.1950 |
2.484 |
2.3417 |
0.4566 |
0.6849 |
|
5 |
0.005 |
24.25 |
0.1150 |
0.2060 |
2.624 |
2.4897 |
0.5129 |
0.7694 |
|
5 |
0.005 |
22.28 |
0.1250 |
0.2240 |
2.854 |
2.7310 |
0.6117 |
0.9176 |
Weight
of water collected=r*V(kg)
M=weight
of water collected/Time(kg/s)
U0=(U2-2gs)1/2
U=M/rA
F=1.5MU0
Sample
calculation:
Weight
of water collected=r*V
=1000*0.005
=5kg
M=5kg/55.25s=0.0905kg/s
F=1.5MU0
=1.5*0.0905*0.8017
=0.1089N
|
Weight of water collected (kg) |
V (m3) |
Time (s) |
Distance of jockey from zero position
(y) |
M(kg/s) |
U(m/s) |
U0(m/s) |
MU0(N) |
F(N) |
|
5 |
0.005 |
58.59 |
0.0245 |
0.0853 |
1.0866 |
0.7029 |
0.060 |
0.12 |
|
5 |
0.005 |
39.85 |
0.0465 |
0.1250 |
1.5924 |
1.3598 |
0.17 |
0.34 |
|
5 |
0.005 |
33.19 |
0.0730 |
0.1510 |
1.9236 |
1.7360 |
0.2621 |
0.524 |
|
5 |
0.005 |
27.53 |
0.0985 |
0.1820 |
2.3185 |
2.1654 |
0.3941 |
0.788 |
|
5 |
0.005 |
26.44 |
0.1145 |
0.1890 |
2.4076 |
2.2605 |
0.4272 |
0.854 |
|
5 |
0.005 |
24.47 |
0.1315 |
0.2040 |
2.5987 |
2.4630 |
0.5025 |
1.005 |
|
5 |
0.005 |
22.31 |
0.1640 |
0.2240 |
2.8535 |
2.7305 |
0.6116 |
1.223 |
Weight
of water collected=r*V(kg)
M=weight
of water collected/Time(kg/s)
U0=(U2-2gs)1/2
U=M/rA
F=2MU0
Sample
calculation:
Weight
of water collected=r*V
=1000*0.005
=5kg
M=5kg/58.59s=0.0853kg/s
F=2MU0
=2*0.0853*0.7029
=0.12N
From
the data collected during the experiment, it is found that for different plate
of vane used, the force exerted on the plate by the water will be different and
it varies from flat, conical and hemispherical plate. This is supported by the
data of the column, distance of jockey from zero position which is the mean of
knowing the force needed to balance the force exerted by the water. We were to
plot graphs of Force versus delivery of momentum for each plate on the same
graph and we found the graphs posses different slope where the values are 2,1.5
and 1.1 for hemispherical, conical and flat plate respectively. We were able to
plot the three plate on the same graph and although the relative slope is
correct where hemispherical has the greater slope followed by conical and flat
plate, but the calculation of the slope will not be correct because the value of
x-axis is the same for all three graphs. So in order to obtain the correct value
of slopes, the individual plotting of the graph has been plotted and the slopes
has been calculated.
When
the water from the nozzle strikes the plate, it has the same initial velocity
For
the three plates but the velocity changes due to the obstruction by the plate
and it will be different for each plate due to the geometrical effect. The
geometry of the hemispherical plate minimize the obstruction of the plate so the
water will flow more freely relative to that of the flat plate.
So,
for the same flow rate, the hemispherical has a relatively higher final velocity
than conical and flat plate.
Conclusions.
As
a conclusion, we found that the value of momentum produced by the striking of
water jet on plates with different geometrical shape will vary where the flat
plate will produced the least momentum and the most is produced from the
hemispherical. The conical will produced the average momentum of the two plates.
From the ideal graph plotting of the force versus momentum, we were able to find
the theoretical slope.
Theoretical
slopes:
Mhemispherical=2
Mconical=1.667
Mflat=1
Percentage
error:
|
Plate shape
|
Theoretical |
Experimental |
%error |
|
Hemispherical |
2 |
2 |
0 |
|
Conical |
1.667 |
1.5 |
10 |
|
Flat |
1 |
1.1 |
-10 |
From
the table above, we can see there are errors for slopes calculation which may be
due to the rounding off and number of decimal points used for plotting the
graphs. There might also error caused by the calculation of the mass flow rate
because it is derived from the primary method of determined the volume flow rate
which can be considered as an approximation.