Through the lack of technical instruments for construction and measurement. A small attempt was made by the team to demonstrate the working of Parshall Flume and Discharge measuring Accessories with support for Dr.-Ing Ramesh Kumar Maskey, Kathmandu University (KU) as part of our hydro-power project.

1. KATHMANDU UNIVERSITY
DHULIKHEL, KAVRE
Final Presentation on Parshall Flume
Group-8
Presented By
Kamal Tolangi Rai (44)
Anuska Ranabhat (45)
Bikram Ray (46)
Khagendra Roka (47)
Pratap Bikram Shahi (48)
Anish Shakya (49)
Project Coordinator
Prof. Dr. Ing. Ramesh
Kumar Maskey

2. Outline
1. INTRODUCTION
2. OBJECTIVES
3. LITERATURE REVIEW
4. METHODOLOGY
5. CHALLENGES AND DEVIATIONS
6. GANT CHART
7. BUDGET ESTIMATION
8. OUTCOME
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3. Introduction
Parshall Flume
● Open channel flow metering device
that was developed to measure the flow
of surface waters and irrigation flows
● Accelerates flow through a contraction
of both the parallel sidewalls and a
drop in the floor at the flume throat
● Used especially for flows containing
suspended solids, like the flow into a
wastewater treatment plant
Fig: Parshall Flume
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4. Equation for discharge in a parshall flume
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5. Components of Parshall Flume
A flume generally consists of three distinct sections.
1. Converging / inlet / approach (dark blue)
2. Throat (grey)
3. Diverging / exit / discharge (light blue)
Source:https://www.openchannelflow.com/blog/sections-of-a-flume-their-location-and-function
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6. 1) Converging/ Inlet section
● Serves to collect and channel the flow into the throat of the flume
● Under free-flow conditions, only a single depth measurement is necessary to
determine the flow rate through the flume
● Change in the cross-sectional area at the primary point of measurement directly
impact a flume’s overall accuracy
2) Throat section
● Narrowest portion of a flume
● The flow is accelerated from sub- to supercritical flow( by change in elevation and
contraction of side walls)
● the throat may have zero length – being formed simply by a transition from the
converging section directly to the diverging section
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7. 3) Diverging/ Exit section
● Minimizes downstream scour and expand the flow back into the channel
● Serves the purpose of energy recovery and transition of the flow back into the
channel
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8. Triangular Notch
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9. Rectangular Notch
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10. Methodology
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11. Dimensions (IS 14371:1996)
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12. CAD
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Fig: Plan of Parshall Flume

13. CAD
All dimensions are in cm 13Fig: Elevation of Parshall Flume

14. CAD:
14
19.3
21.5
11.5
40
Fig: Rectangular Notch All dimensions are in cm

15. CAD:
15
Fig: Triangular Notch
21.5
10
20
40
All dimensions are in cm

16. 16
Fig: Installation of Parshall Flume in the test channel

17. 17
Fig: Initial setup of experiment

18. 18Fig: Installation of Triangular notch

19. 19
Fig: Overflowing of earthen dam

20. 20Video: Measurement of flow

21. 21
Fig: Initial fabrication of the model with ply

22. Procedure (Parshall Flume)
● The dimension of Parshall Flume was selected as per IS 14371:1996
● Plywood was marked with marker, pencil and scale/measuring tape according to the
dimension of the Parshall Flume.
● With help of ripsaw the wood was cut along the marking.
● The Parshall Flume segments was smoothed out with the help of sandpaper.
● Water sealed Parshall Flume was constructed out of glass, the glass was glued
together with the help of M-seal and Silicone Gel sealant.
● The Flume was tested for discharge.
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23. Procedure (V Notch)
● The channel was checked for seepage.
● The V-notch was installed at the end of the channel and the water was supplied.
● As the water flowed in the channel, the water head using a scale was measured.
● The flow was adjusted to maximum possible discharge and the height ‘H’ is noted. This
gives the head over the notch.
● The Cd was assumed.
● The discharge Q was calculated.
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.

24. Procedure (Rectangular Notch)
● The channel was checked for seepage.
● The Rectangular Notch was installed at the end of the channel and the water was
supplied.
● As the water flowed in the channel, the water head using a scale was measured.
● The flow was adjusted to maximum possible discharge and the height ‘H’ is noted.
This gives the head over the notch.
● The Cd was assumed.
● The discharge Q was calculated.
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25. RESULT (Parshall Flume)
25
S.N.
Free Flow Condition Submerged Flow Condition
Ha (m) Q (L/s) Ha (m) Hb (m) % submergence (Hb/Ha)*100 Q (L/s)
1 0.07 1.95 0.07 0.045 64% 1.811
For 2” throated Parshall Flume:
K= 0.676 ft3/s and Ha = 7 cm = 0.229659 ft, n= 1.55
Q = kHn = 1.95 L/s

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27. 27

28. 28

29. RESULT (V-NOTCH)
● Crest Height (h)= 11cm
● b= 20 cm
● Overall height = 22 cm
● Assumed Cd = 0.62
● Flow Head (H) = 3 cm
● Q= 0.228 L/s
● Flow Head (H) = 4.5 cm
● Q= 0.629 L/s
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30. RESULT (RECTANGULAR NOTCH)
● Crest Height (h)= 11.5 cm
● b= 19.5 cm
● Overall height = 21.5cm
● Assumed Cd = 0.62
● Flow Head (H)= 2.5 cm
● Q = 1.41 L/s
● Flow Head (H) = 3.5 cm
● Q = 2.337 L/s
● Flow Head (H) = 4.5 cm
● Q= 3.408 L/s
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31. Deviations
● Initial attempt to construct a 3D model was dropped as the cost of material for 3D
printing as per design came to be very expensive. (1gm ~ Rs 18-20)
● Later attempt to construct the flume using Agrakh (water resistant wood) was
dropped as it too came to be too expensive (1ft * 1ft ~Rs 7000)
● Attempt of construction of larger model was dropped due to lack of materials
available.
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32. Additional Test Data
● Height: 18.5 cm (U/S), 40 cm (D/S)
● Width: 52 cm
● Crest thickness: 8 cm
● Water Retained: 76 Liters (4L*19)
● Maximum rise in water canal: 4cm
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33. Work Schedule
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34. Budget Estimation
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Special thanks to Dr.-Ing Ramesh Kumar Maskey for supporting, instructing
and directing in construction and development of our model

36. References
● Bureau of Indian Standards (BIS). (1996)._ Measurement of liquid flow in open
channels - Parshall and SANIIRI flumes_(ISO Standard No. 14371:1996). Retrieved
from https://archive.org/details/gov.in.is.14371.1996/page/n13
● Parshall Flume User’s Manual [PDF file]. Retrieved from
https://www.openchannelflow.com/assets/uploads/documents/Parshall_Flume_Users_
Manual.pdf
● Shen, John.DISCHARGE CHARACTERISTICS OF TRIANGULAR-NOTCH THIN-
PLATE WEIRS [PDF file]. Retrieved from https://pubs.usgs.gov/wsp/1617b/report.pdf
● Rajput, R.K., A Textbook of Fluid Mechanics
● https://www.openchannelflow.com/blog/universal-equation-parshall-flume-submergence
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