Hydraulic Engineering Eng. Osama Dawoud

Lecture 4 Head Losses in Pipelines Part2

Minor Losses Additional losses due to entries and exits, fittings and valves are traditionally referred to as minor losses

Losses due to contraction A sudden contraction A sudden contraction in a pipe usually causes a marked drop in pressure in the pipe due to both the increase in velocity and the loss of energy to turbulence.

Value of the coefficient K c for sudden contraction V2V2V2V2

gradual pipe transition confusor Head losses due to pipe contraction may be greatly reduced by introducing a gradual pipe transition known as a confusor

Losses due to Enlargement A sudden Enlargement A sudden Enlargement in a pipe

gradual pipe transition diffusor Head losses due to pipe enlargement may be greatly reduced by introducing a gradual pipe transition known as a diffusor

Loss due to pipe entrance General formula for head loss at the entrance of a pipe is also expressed in term of velocity head of the pipe

Loss at pipe exit (discharge head loss) In this case the entire velocity head of the pipe flow is dissipated and that the discharge loss is

Loss of head in pipe bends

Loss of head through valves

Minor loss calculation using equivalent pipe length

Example 1 In the figure shown two new cast iron pipes in series, D1 =0.6m, D2 =0.4m length of the two pipes is 300m, level at A =80m, Q = 0.5m3/s (T=10 o C).there are a sudden contraction between Pipe 1 and 2, and Sharp entrance at pipe 1. Fine the water level at B e = 0.26mm v = 1.31×10-6 Q = 0.5 m3/s

Solution

Z B = 80 – = m

Example 2 A pipe enlarge suddenly from D1=240mm to D2=480mm. the H.G.L rises by 10 cm calculate the flow in the pipe

Solution

Power in pipelines

Calculate the max transported power through pipe line The max transported power through pipe line at

Efficiency in power transportation through pipelines

Example 3 Pipe line has length 3500m and Diameter 0.5m is used to transport Power Energy using water. Total head at entrance = 500m. Determine the maximum power at the Exit. F = 0.024

Lecture 5 Pipelines in series & parallel

Pipelines in Series

Pipelines in Parallel

Example 4 الشكل التالي يوضح نظام مكون من أنابيب من الحديد المجلفن، الأنبوب الرئيسي قطره 20 سم بطول 4 م، بين الوصلتين 1 و 2 ، تم تثبيت صمام سكينة Gate Valve ، عند نهايته مباشرة قبل الوصلة 2 ، الأنبوب المتفرع قطره 12 سم بطول 6.4 م. يتكون من وصلات مرفقية بزاية 90o (R/D = 2.0) وصمام منزلي. يتدفق الماء عبر النظام بحيث يكون التدفق الكلي 0.26 م 3/ ث عند درجة حرارة 10o مئوية، احسب التدفق في كل أنبوب عندما تكون الصمامات مفتوحة بالكامل.

Example 4