Introduction
The flow of a given volume of fluid through a pipe requires a given amount of energy. In order for fluid flow to occur, there must be pressure or energy difference. During fluid flow through a pipe, energy is lost. The main causes of this loss are the resistance encountered by the fluid in the process of its movement through the pipe. Viscosity is one of the most common forms of resistance to fluid flow through a pipe (Noltingk, 1985, p. 5). Fluids that have high viscosity tend to exhibit high resistance while flowing through a pipe (Considine and Considine, 1999, p. 1445). On the other hand, fluids that have low viscosity have lower resistance than those with high viscosity. Another form of resistance to fluid flow is the tendency to stick to surfaces. In this case, liquids that stick to the surface of the pipes tend to be more resistant to flow than those that do not stick to the surfaces of the pipes.
Head loss is influenced by a variety of factors that include the following: flow rate, the degree of roughness of the inner walls of the pipe in which the fluid flows, viscosity of the fluid in question, fittings, the diameter of the inside of the pipe in which the fluid is to flow, corrosion and scale deposit, length of the pipe, and the degree of straightness of the pipe (Ali, 2011, p. 27).
Even though fittings of a piping system such as valves and elbows are necessary in a piping system, they disrupt the smooth flow of fluid. This disruption causes increased magnitude of friction, hence increasing head loss. The inside diameter of the pipe is also a significant factor influencing head loss. When the inside diameter is increased, the fluid’s flow area increases too. As a result, the velocity of the fluid reduces, thus causing the friction also to reduce. In short, an increase in the inner diameter of a pipe leads to a decrease in the head loss (Bloch and Budris, 2004, p. 123). Pipes with large amounts of corrosion and scale deposits tend to exhibit high degree of roughness. Consequently, they tend to elicit high magnitude of friction. High friction, in turn, results in an increase in head loss.
The length of a pipe does not affect the amount of head loss per foot length. The magnitude of head loss per foot length remains constant even if the length of the pipe is increased. However, for long pipes, the total head loss is high. The shape of the pipe, however, greatly influences the magnitude of the head loss. In pipes that are not straight, the liquid flowing within tend to encounter obstacles that prevent it from flowing smoothly. This results in high resistance to the flow. On the other hand, straight pipes do not exhibit much resistance since the flow of the liquid in them does not encounter obstacles.
The resistance to the fluid flow through a pipe causes a presser drop. Besides, a pressure gain may also be realized depending on an elevation change between the start and end of the pipe. Various factors determine the pressure change across the pipe. Such factors include the following among others: friction between the adjacent layers of the flowing liquid, friction between the flowing liquid and the inner wall of the pipe, pressure loss caused by a change in the elevation of the pipe, and pressure gain caused by the addition of the fluid head to the pump.
Methods
The set-up of the experiment was arranged as shown in the figure below:
Results
Valve position 1
∆p
∆ρ=70.5-28.4
∆ρ=42.1 cm
Time
Average time=15.41+15.94+15.343
Average time=15.563s
Velocity of flow (v)
v=0.01m315.563s
v=6.425*10-4 m3/s
ʋ=(4*6.425*10-4 m3/s)/(π*0.017m2
ʋ=2.8306 m/s
Reynolds Number(Re)
Re=2.8306ms-1*0.017m1.004*10-6m2s-1
Re=47928.48
λ
λ=0.3164447928.48
λ=0.316414.7961
hv
hv=0.0214*0.8m*2.830622*0.012*9.81m2s2
hv=0.4113m
∆ρ=0.421m
hv=0.4113m
∆ρ-hv=0.0097
Valve position 2
∆p
56.8-33.3
∆ρ=23.5 cm
Average time
Average time=t1+t2+t33
Average time=21.37+21.59+21.383
Aerage time=21.45s
Change in volume ∆V
∆v=30-20
∆v=0.01m3
Velocity (ύ)
ύ=0.01m321.45s
ύ=0.0004662 m3s-1
ύ=4.662*10-4m3s-1
Ѵ
Ѵ=4*4.662*10-4m3s-1π*0.0172
Ѵ=2.0539ms-1
Reynolds Number(Re)
Re=2.0539ms-1*0.0171.004*10-6m2s-1
Re=34777.1912
λ
λ=0.3164434777.1912
λ=0.0232
hv
hv=0.0232*0.8m*2.0339ms-122*0.017m*9.81ms-2
hv=0.2347m
∆ρ=23.5cm
∆ρ-hv=0.0003
Valve position 3
Change in pressure (∆p)
∆ρ=45.3-36.5
∆ρ=8.8 cm
Average time
Average time=t1+t2+t33
Average time=38.28s+38.25s+38.69s3
Average time=38.41s
Change in volume
∆v=30-20
∆v=10 l
∆v=0.01m3
Volume flow rate (ύ)
ύ=0.01m338.41s
ύ=2.6035*10-4m3s-2
Ѵ
Ѵ=4*2.6035*10-4m3s-1π*0.017m2
Ѵ=1.1470ms-1
Reynolds Number(Re)
Re=1.1470ms-1*0.017m1.004*10-6m2s-1
Re=19421.3147
λ
λ=0.3164419421.3147
hv
hv=0.0268*0.8m*1.1470ms-120.017m*2*9.81ms-2
hv=0.0846m
∆ρ=0.0846m
∆ρ=8.8cm
hv=0.0846m
∆ρ-hv=0.034
References
Ali, H., 2011. Practices of irrigation & on-farm water management (Vol. 2). Springer Science & Business Media.Top of Form
Bloch, H.P. and Budris, A.R., 2004. Pump user's handbook: life extension. The Fairmont Press, Inc..
Considine, D. M., & Considine, G. D., 1999. Van Nostrand's scientific encyclopedia. New York, Wiley.Top of Form
Johnson, L. R., & Byrne, J. H., 2003. Essential medical physiology. Amsterdam, Elsevier Academic Press.
Noltingk, B. E., 1985. Jones' instrument technology. Volume 1, Volume 1. http://public.eblib.com/choice/publicfullrecord.aspx?p=1838782.Top of Form
