4wings.com Hovercraft development 47751 Michigan ave., Port Isabel - 78578 - Texas, US Tel.: (956)943 5150

4wings.com

Hovercraft development
47751 Michigan ave. , Port Isabel, TX, 78578
Tel:(956) 943-5150










Velocity and pressure drop in pipes formulas and calculator

Velocity
The velocity of hydraulic fluid through a conductor (pipe, tube or hose) is dependent on flow rate and cross sectional area. Recommended fluid velocities through pipes and hoses in hydraulic systems are as follows:

Service Velocity (ft/sec) Velocity (m/sec)
suction/intake 2-4 0.6 - 1.2
return 4 - 13 1.5 - 4
pressure / discharge 7 - 8 2 - 5.5
Use values at the lower end of the range for lower pressures or where operation is continuous. Refer to the flow/velocity nomograms at the centre of this file  for more information, alternatively, fluid velocity can be calculated using the following formula:

v = Q � 0.408
            D�

Where :
v = velocity in feet per second (ft/sec)
Q = flow rate in US gallons per minute (USgpm)
D = inside diameter of pipe or hose in inches (in)

In metric units:

v = Q � 21.22
            D�

Where :
v = velocity in metres per second (m/sec)
Q = flow rate in litres per minute (L/min)
D = inside diameter of pipe or hose in millimetres (mm)


Pressure drop

Friction between the fluid flowing through a conductor and its inside wall causes losses, which are quantified as pressure drop. Pressure drop in conductors is an important consideration for the designer especially in systems where long pipe or hose runs are necessary. The pressure drop over a length of pipe or hose can be calculated using the following formula, which for ease of calculation uses metric units.

Before proceeding to the pressure drop calculations, the following variables need to be known:

Flow rate in litres per minute (L/min) Q
Inside diameter of pipe or hose in millimetres (mm) D
Kinematic viscosity of fluid (at operating temperature) in centistokes (cSt) ν
Density of the fluid in kilograms per cubic metre (kg/m�) ρ
Length of the pipe, tube or hose in metres (m) L

1. Calculate fluid velocity:

v = Q � 21.22
             D�

Where:

v = velocity in metres per second (m/sec)
Q = flow rate in litres per minute (L/min)
D = inside diameter of pipe or hose in millimetres (mm)


2. Calculate the Reynolds Number (Re):

Re = 1000 � v � D
ν

Where:

Re = Reynolds Number
v = velocity in metres per second (m/sec)
D = inside diameter of pipe or hose in millimetres (mm)
ν = kinematic viscosity of fluid (at operating temperature) in centistokes (cSt)

3. Calculate the friction factor (f)

The formula used to calculate the friction factor is dependent on the magnitude of the Reynolds Number.
If the Reynolds Number is less than 2300, flow is laminar and the following formula is used to calculate the friction factor:

f = 64
     Re

Where :

f = friction factor
Re = Reynolds Number < 2300

If the Reynolds Number is between 2300 and 4000, flow is transition and greater than 4000 flow is turbulent.
For Reynolds Numbers greater than 2300 and less than 100,000 the following formula can be used to calculate the friction factor:

f = 0.3164 � Re - 0.25

Where :

f = friction factor
Re = Reynolds Number > 2300 and < 100,000

In instances where the Reynolds Number is greater than 100,000, friction is highly dependant on the roughness of the conductor’s inner surface. In these cases Colebrook’s equation, which considers pipe roughness, is used to calculate the friction factor.
However, due to the relatively low fluid velocities and high fluid viscosities present in hydraulic systems, Reynolds Numbers of this magnitude should not be encountered.

4. Calculate the pressure drop:

Finally, pressure drop can be calculated using the following formula:

Δp = v� � f � L � ρ
2D

Where :

Δp = pressure drop in Pascals (Pa)
v = velocity in metres per second (m/sec)
f = friction factor
L = length of pipe or hose in metres (m)
ρ = density of the fluid in kilograms per cubic metre (870-890 kg/m� for hydraulic oil)
D = inside diameter of pipe or hose in metres (m)

Conversions:
US gallon    *  3.785   = Liter
inch             *  25.4     = Milimetre
inch             *  0.0254 = Metre
feet              *  0.3048 = Metre
lb/ft3            *  16.02   = kg/m3
Pascal (Pa)   /   100000= bar
Pascal (Pa)   *   0.000145 = psi

metric flow / velocity nomogram


US - Flow / velocity nomogram
� 2013 www.4wings.com

Kinematic viscosity for some common fluids are indicated below:


Liquid Temperature Kinematic Viscosity
(oF) (oC) CentiStokes (cSt) Seconds Saybolt Universal (SSU)
Acetaldehyde CH3CHO 61
68		 16.1
20		 0.305
0.295		 36
Acetic acid - vinegar - 10% CH3COOH 59 15 1.35 31.7
Acetic acid - 50% 59 15 2.27 33
Acetic acid - 80% 59 15 2.85 35
Acetic acid - concentrated glacial 59 15 1.34 31.7
Acetic acid anhydride (CH3COO)2O 59 15 0.88
Acetone CH3COCH3 68 20 0.41
Alcohol - allyl 68
104		 20
40		 1.60
0.90 cp		 31.8
Alcohol - butyl-n 68 20 3.64 38
Alcohol - ethyl (grain) C2H5OH 68
100		 20
37.8		 1.52
1.2		 31.7
31.5
Alcohol - methyl (wood) CH3OH 59
32		 15
0		 0.74
1.04
Alcohol - propyl 68
122		 20
50		 2.8
1.4		 35
31.7
Aluminum sulfate - 36% solution 68 20 1.41 31.7
Ammonia 0 -17.8 0.30
Aniline 68
50		 20
10		 4.37
6.4		 40
46.4
Asphalt RC-0, MC-0, SC-0 77
100		 25
37.8		 159-324
60-108		 737-1.5M
280-500
Automatic crankcase oil SAE 10W 0 -17.8 1295-max 6M-max
Automatic crankcase oil SAE 10W 0 -17.8 1295-2590 6M-12M
Automatic crankcase oil SAE 20W 0 -17.8 2590-10350 12M-48M
Automatic crankcase oil SAE 20 210 98.9 5.7-9.6 45-58
Automatic crankcase oil SAE 30 210 98.9 9.6-12.9 58-70
Automatic crankcase oil SAE 40 210 98.9 12.9-16.8 70-85
Automatic crankcase oil SAE 50 210 98.9 16.8-22.7 85-110
Automotive gear oil SAE 75W 210 98.9 4.2 min 40 min
Automotive gear oil SAE 80W 210 98.9 7.0 min 49 min
Automotive gear oil SAE 85W 210 98.9 11.0 min 63 min
Automotive gear oil SAE 90W 210 98.9 14-25 74-120
Automotive gear oil SAE 140 210 98.9 25-43 120-200
Automotive gear oil SAE150 210 98.9 43 - min 200 min
Beer 68 20 1.8 32
Benzene (Benzol) C6H6 32
68		 0
20		 1.0
0.74		 31
Bone oil 130
212		 54.4
100		 47.5
11.6		 220
65
Bromine 68 20 0.34
Butane-n -50
30		 -1.1 0.52
0.35
Butyric acid n 68
32		 20
0		 1.61
2.3 cp		 31.6
Calcium chloride 5% 65 18.3 1.156
Calcium chloride 25% 60 15.6 4.0 39
Carbolic acid (phenol) 65
194		 18.3
90		 11.83
1.26 cp		 65
Carbon tetrachloride CCl4 68
100		 20
37.8		 0.612
0.53
Carbon disulfide CS2 32
68		 0
20		 0.33
0.298
Castor oil 100
130		 37.8
54.4		 259-325
98-130		 1200-1500
450-600
China wood oil 69
100		 20.6
37.8		 308.5
125.5		 1425
580
Chloroform 68
140		 20
60		 0.38
0.35
Coconut oil 100
130		 37.8
54.4		 29.8-31.6
14.7-15.7		 140-148
76-80
Cod oil (fish oil) 100
130		 37.8
54.4		 32.1
19.4		 150
95
Corn oil 130
212		 54.4
100		 28.7
8.6		 135
54
Corn starch solution, 22  70
100		 21.1
37.8		 32.1
27.5		 150
130
Corn starch solution, 24  70
100		 21.1
37.8		 129.8
95.2		 600
440
Corn starch solution, 25 70
100		 21.1
37.8		 303
173.2		 1400
800
Cotton seed oil 100
130		 37.8
54.4		 37.9
20.6		 176
100
Crude oil 48o API 60
130		 15.6
54.4		 3.8
1.6		 39
31.8
Crude oil 40o API 60
130		 15.6
54.4		 9.7
3.5		 55.7
38
Crude oil 35.6o API 60
130		 15.6
54.4		 17.8
4.9		 88.4
42.3
Crude oil 32.6o API 60
130		 15.6
54.4		 23.2
7.1		 110
46.8
Decane-n 0
100		 17.8
37.8		 2.36
1.001		 34
31
Diethyl glycol 70 21.1 32 149.7
Diethyl ether 68 20 0.32
Diesel fuel 2D 100
130		 37.8
54.4		 2-6
1.-3.97		 32.6-45.5
-39
Diesel fuel 3D 100
130		 37.8
54.4		 6-11.75
3.97-6.78		 45.5-65
39-48
Diesel fuel 4D 100
130		 37.8
54.4		 29.8 max
13.1 max		 140 max
70 max
Diesel fuel 5D 122
160		 50
71.1		 86.6 max
35.2 max		 400 max
165 max
Ethyl acetate CH3COOC2H3 59
68		 15
20		 0.4
0.49
Ethyl bromide C2H5Br 68 20 0.27
Ethylene bromide 68 20 0.787
Ethylene chloride 68 20 0.668
Ethylene glycol 70 21.1 17.8 88.4
Formic acid 10% 68 20 1.04 31
Formic acid 50% 68 20 1.2 31.5
Formic acid 80% 68 20 1.4 31.7
Formic acid concentrated 68
77		 20
25		 1.48
1.57cp		 31.7
Freon -11 70 21.1 0.21
Freon -12 70 21.1 0.27
Freon -21 70 21.1 1.45
Furfurol 68
77		 20
25		 1.45
1.49cp		 31.7
Fuel oil 1 70
100		 21.1
37.8		 2.39-4.28
-2.69		 34-40
32-35
Fuel oil 2 70
100		 21.1
37.8		 3.0-7.4
2.11-4.28		 36-50
33-40
Fuel oil 3 70
100		 21.1
37.8		 2.69-5.84
2.06-3.97		 35-45
32.8-39
Fuel oil 5A 70
100		 21.1
37.8		 7.4-26.4
4.91-13.7		 50-125
42-72
Fuel oil 5B 70
100		 21.1
37.8		 26.4-
13.6-67.1		 125-
72-310
Fuel oil 6 122
160		 50
71.1		 97.4-660
37.5-172		 450-3M
175-780
Gas oils 70
100		 21.1
37.8		 13.9
7.4		 73
50
Gasoline a 60
100		 15.6
37.8		 0.88
0.71
Gasoline b 60
100		 15.6
37.8		 0.64
Gasoline c 60
100		 15.6
37.8		 0.46
0.40
Glycerin 100% 68.6
100		 20.3
37.8		 648
176		 2950
813
Glycerin 50% water 68
140		 20
60		 5.29
1.85 		43
Glucose 100
150		 37.8
65.6		 7.7M-22M
880-2420		 35M-100M
4M-11M
Heptanes-n 0
100		 -17.8
37.8		 0.928
0.511
Hexane-n 0
100		 -17.8
37.8		 0.683
0.401
Honey 100 37.8 73.6 349
Ink, printers 100
130		 37.8
54.4		 550-2200
238-660		 2500-10M
1100-3M
Insulating oil 70
100		 21.1
37.8		 24.1 max
11.75 max		 115 max
65 max
Kerosene 68 20 2.71 35
Jet Fuel -30. -34.4 7.9 52
Lard 100
130		 37.8
54.4		 62.1
34.3		 287
160
Lard oil 100
130		 37.8
54.4		 41-47.5
23.4-27.1		 190-220
112-128
Linseed oil 100
130		 37.8
54.4		 30.5
18.94		 143
93
Mercury 70
100		 21.1
37.8		 0.118
0.11
Methyl acetate 68
104		 20
40		 0.44
0.32
Methyl iodide 68
104		 20
40		 0.213
0.42
Menhaden oil 100
130		 37.8
54.4		 29.8
18.2		 140
90
Milk 68 20 1.13 31.5
Molasses A, first 100
130		 37.8
54.4		 281-5070
151-1760		 1300-23500
700-8160
B, second 100
130		 37.8
54.4		 1410-13.2M
660-3.3M		 6535-61180
3058-15294
C, blackstrap 100
130		 37.8
54.4		 2630-55M
1320-16.5M		 12190-255M
6120-76.5M
Naphthalene 176
212		 80
100		 0.9
0.78
Neatstool oil 100
130		 37.8
54.4		 49.7
27.5		 230
130
Nitrobenzene 68 20 1.67 31.8
Nonane-n 0
100		 -17.8
37.8		 1.728
0.807		 32
Octane-n 0
100		 -17.8
37.8		 1.266
0.645		 31.7
Olive oil 100
130		 37.8
54.4		 43.2
24.1		 200
Palms oil 100
130		 37.8
54.4		 47.8
26.4
Peanut oil 100
130		 37.8
54.4		 42
23.4		 200
Pentane-n 0
80		 17.8
26.7		 0.508
0.342
Petrolatum 130
160		 54.4
71.1		 20.5
15		 100
77
Petroleum ether 60 15.6 31(est) 1.1
Propionic acid 32
68		 0
20		 1.52
1.13		 31.5
Propylene glycol 70 21.1 52 241
Quenching oil
(typical)

100-120 20.5-25
Rapeseed oil 100
130		 37.8
54.4		 54.1
31		 250
145
Rosin oil 100
130		 37.8
54.4		 324.7
129.9		 1500
600
Rosin (wood) 100
200		 37.8
93.3		 216-11M
108-4400		 1M-50M
500-20M
Sesame seed oil 100
130		 37.8
54.4		 39.6
23		 184
110
Sodium chloride 5% 68 20 1.097 31.1
Sodium chloride 25% 60 15.6 2.4 34
Sodium hydroxide (caustic soda) 20% 65 18.3 4.0 39.4
Sodium hydroxide (caustic soda) 30% 65 18.3 10.0 58.1
Sodium hydroxide (caustic soda) 40% 65 18.3

Soya bean oil 100
130		 37.8
54.4		 35.4
19.64		 165
96
Sperm oil 100
130		 37.5
54.4		 21-23
15.2		 110
78
Sulphuric acid 100% 68
140		 20
60		 14.56
7.2 		76
Sulphuric acid 95% 68 20 14.5 75
Sulphuric acid 60% 68 20 4.4 41
Sulphuric acid 20%


3M-8M
650-1400
Tar, coke oven 70
100		 21.1
37.8		 600-1760
141-308		 15M-300M
2M-20M
Tar, gas house 70
100		 21.1
37.8		 3300-66M
440-4400		 2500
500
Tar, pine 100
132		 37.8
55.6		 559
108.2		 200-300
55-60
Toluene 68
140		 20
60		 0.68
0.38 		185.7
Triethylene glycol 70 21.1 40 400-440
185-205
Turpentine 100
130		 37.8
54.4		 86.5-95.2
39.9-44.3		 1425
650
Varnish, spar 68
100		 20
37.8		 313
143
Water, distilled 68 20 1.0038 31
Water, fresh
 60
130		 15.6
54.4		 1.13
0.55		 31.5
Water, sea

1.15 31.5
Whale oil 100
130		 37.8
54.4		 35-39.6
19.9-23.4		 163-184
97-112
Xylene-o 68
104		 20
40		 0.93
0.623



















Unit Conversion

This calculator computes the pressure drop across an orifice, which can be used to measure the flowrate of the fluid