Civil Insight: A Technical Magazine Volume 2 | Page 72

72
PROJECTS
CIVIL INSIGHT 2018
DESIGN OF THE CANAL OBSERVATION
Blocks were used to build a canal of 2.2cm thickness
for the wall, 1.2cm for the base, length 125cm,
height 22.5cm and width 11cm. The blocks are fi xed
together using nails and glues. Holes were drilled
onto each side to attach the bearing and shaft of
the turbine. Depth of water at upstream, d 1 =0.032, 0.032, 0.034
(m)
Depth of water at downstream, d 2 =0.025, 0.027 (m)
Velocity, V 1 =1.50 m/s
Discharge, Q p = 2 lps(bearingside; entrance losses
were excluded)
Depths:
d 1 = (0.032+0.032+0.034)/3 =0.032 m
d 2 = (0.025+0.027)/2 =0.026m
Velocity, V 2 =(d 1 /d 2 ) *V 1 = (0.032/0.026) *1.50 = 1.81 m/s
Hydraulic pressure force:
Fig: Channel
F p ȡJGíGíǻGX$ (ǻGX is neglected, depths being too
small)
=1000*9.81*(0.032-
ʌ

OHQJWKDQGUDGLXV
of blade = 0.1m,0.035m)
= 0.65 N
Counter-acting Acceleration Force:
Fig: Bearing
After building all the components, they were fi tted
together and experimented on.
F A = Q p ȡY 2 ív 1 )
=0.002*1000*(1.81-1.5)
=0.62 N
Output power:
P out = (Aρg(d 1 −d 2 −Δdu) −Qρ(v 2 −v 1 )) v 2
= (0.65-0.62) *1.81
= 0.054 W
Input power:
P in = (d 1 −d 2 ) ρgQ
= (0.032-0.026) *1000*9.81*0.002
= 0.117 W
⸫ Efficiency, η% = (Pout/P in ) *100 = 46.15%
BIBLIOGRAPHY
Senior, J., Wiemann, P., & Muller, G. “The rotary
hydraulic pressure machine for very low head
hydropower sites”, University of Southampton, U.K.
Harvey, A, & Brown, A (1992). Micro-Hydro Design
Manual. Stockholm: ITDG Publishing.
Pokharel, N., Parajuli, P. & Koirala, P. (2016).
Computational and experimental study of an ultra-
low head turbine.
Baral, S. (2016). Fundamentals of Hydropower
Engineering . Bhotahiti, Kathmandu: National Book
Center.