Hydraulics

Hydraulics
25.02.2011
Exercise - 1
Q1. Water at 10°C flows in a 150 mm diameter
pipe at a velocity of 5.5 m/sec. Is this flow
laminar or turbulent?
Re>4000 turbulent
Re<4000 laminar
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Re 
IKU - Hydraulics - Murat Aksel
V .D

2
Exercise - 1
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Exercise - 1
Re 
V .D

 water(10C )  1.307 x10
6
5.5 x0.15
Re 
 634000
6
1.307 x10
Re  634000  4000
Flow is turbulent!
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Model-Velocity-Laminar Flow
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Model-Velocity-Turbulent Flow
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Model-Velocity
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Model-Pressure
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Exercise - 2
Gasoline is being discharged from a pipe, as shown in figure. The pipe roughness
(ɛ) is 0.500 mm, and the pressure at point 1 is 2500 kPa. Find the pipe diameter
needed to discharge gasoline at a rate of 0.10 m³/s. Neglect any minor losses.
(SGgasoline = 719 kg/m³, μgasoline = 2.92x10¯⁴)
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IKU - Hydraulics - Murat Aksel
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Exercise - 2
V12
P2 V22

 z1 

 z2  hL
 2g
 2g
P1
L V2
hL  f
D 2g
Bernoulli Eq.
Darcy-Weisbach Head Loss Eq.
965.5 V 2
V22
hL  f
 49.2 f
D 2 x9.81
D
2500
V12
V22
V22

 82.65  0 
 66.66  49.2 f
7060 19.62
19.62
D
Q  V .A
Q  V1. A1  V2 . A2  A1  A2  V1  V2
V22
f
 0.332
D
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Exercise - 2
V22
f
 0.332
D
V2 
Q
0.1
2


0
.
1273
/
D
A2  D 2 / 4

0.1273 / D 
f
2 2

 0.332
D
D  (0.04881 f )1/ 5
Assume f = 0.02
f  0.02  D  0.04881x0.02 
1/ 5
 0.25m
V2  0.1273 / 0.252  2.037 m / s
Re 
DV 719 x0.25 x 2.037
6


1
.
25
x
10
2.92 x104 

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Exercise - 2
  0.0005m
 / D  0.0005 / 0.25  0.002
From Moody Diagram
f = 0.0235
f  0.0235  D  0.04881x0.0235
1/ 5
 0.2582m
V2  0.1273 / 0.2582 2  1.91m / s
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