CALCULATION OF HEAD LOSSES IN U-PVC PIPES

The term "Head Loss" refers to the difference in distances a liquid would flow a 1-meter pipe without friction and with friction.
When a liquid flows through the pipe, the flow rate decreases due to friction with the inner surface of the pipe and the increase and decrease in pressure at turns, contraction and expansions called as "Water Hammer". In other words, the liquid cannot pass through the pipe at calculated amounts and speeds. For this reason, the amount of head loss caused by friction with the pipe inner wall and water hammer should be taken into account during the determination of pipe diameter and pressure.
When calculating head loss, the Hazen-Williams formula is used.
Head Loss is calculated with: J=6,815 . V1,852
C13852 . d1,167
formula.
Here, J=Head Loss (m/m)
V=Fluid Flow Rate (m/sn)
C=roughness coefficient (no unit)
D= Inner diameter of pipe (m)
C value for polyethylene and PVC pipes:
Diameter = Ø16 - Ø20 mm > 130,
Diameter = Ø25 - Ø32 mm > 140,
Daimater => Ø40 > 150 .
In Ø = V.A formula, Q = Flow Rate (M3 / s)
Although there are detailed sheets to calculate the head losses that will occur in the auxiliary parts, the amount of head loss that will occur in these parts is practically considered to be 5% of the head loss that is calculated in the pipe.
Water Hammer: When a fluid travels in a plastic tube, the pressure distribution rate in the pipe varies due to the contraction or expansion of the diameter, or due to the rotation.
The required distribution rate of the pressure wave in the pipe, the rate is calculated by

formula.(m/s)
In this formula, d = internal diameter of pipe (m)
e = thickness of pipe (M)
K = the ratio of water flexibility to the flexibility of pipe (without unit).
The K value is taken as 33,3 for PVC pipes
99,9 for PE 100 pipes
and 111 for PE 63 pipes.
Water Hammer is calculated with (m) = V.a/G formula.
In this formula, V = velocity of liquid in pipe (m/sec),
g = gravitational acceleration (m/sec2),
As can be seen from this comparative table, PVC pipes transmit pressure better. In other words, a liquid in the PVC pipe is moving faster than it is in the polyethylene pipe. This is an advantage of PVC pipe. Because the fluid moves more smoothly in the pipe, it will not wear out the pipe over time.
DISTRIBUTION OF PRESSURE WAVE IN U-PVC PIPES:
Di~ cap (mm) 4 ATU 6 ATU 10 ATU 16 ATU 20 ATU
a a/g a a/g a a/g a a/g a a/g
20 479,83 48,93 543,15 55,38
25 483,15 49,27 534,04 54,45
32 389,00 39,67 479,83 48,93 529,82 54,02
40 335,70 34,23 378,88 38,63 479,83 48,93 535,57 54,61
50 299,63 30,55 380,92 38,84 476,48 48,59 534,04 54,45
63 300,43 30,63 379,37 38,68 478,50 48,79 534,23 54,47
75 267,55 27,28 296,23 30,21 380,92 38,84 478,71 48,81 529,95 54,04
90 243,97 24,88 299,63 30,55 380,02 38,75 477,97 48,74 531,32 54,18
110 243,97 24,88 270,61 27,59 338,80 34,55 427,34 43,57 475,26 48,46
125 243,97 24,88 272,03 27,74 339,79 34,65 424,38 43,27 475,14 48,45
140 243,97 24,88 273,14 27,85 340,56 34,73 424,70 43,31 475,04 48,44
160 243,97 24,88 273,14 27,85 341,37 34,81 425,03 43,34 475,64 48,50
180 243,97 24,88 266,92 27,22 339,49 34,62 425,29 43,37 476,11 48,55
200 243,97 24,88 270,36 27,57 340,24 34,69 425,49 43,39 474,80 48,41
225 243,97 24,88 270,05 27,54 338,99 34,57 425,70 43,41 475,73 48,51
250 241,49~ 24,62 272,03 27,74 339,79 34,65 424,38 43,27 475,14 48,45

280

315

241,7
242,0
24,65
24,68
271,16
270,05
27,65
27,54
338,95
339,85
34,56
34,65
424,70
424,99
43,31
43,34
475,04
475,31
48,44
48,47
355 242,2 24,70 270,40 27,57 339,38 34,61 425,26 43,36 474,87 48,42
400 242,4 24,72 270,36 27,57 339,11 34,58 424,57 43,29 474,80 48,41

a : The speed of pressure distribution (in/s) a/g acceleration of the pressure distribution (s)

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