Endress+Hauser Promass 40 - Pressure Loss Formulas

10 Technical data Promass 40
56 Endress+Hauser
Pressure loss Pressure loss depends on the properties of the fluid and on the flow. The following for-
mulas can be used to approximately calculate the pressure loss:
Pressure loss formulas for Promass E
Pressure loss coefficient for Promass E
Fig. 22: Pressure loss diagram with water
Reynolds number
Re
≥ 2300
1)
Re < 2300
∆p = pressure loss [mbar]
υ = kinematic viscosity [m
2
/s]
= mass flow [kg/s]
ρ = fluid density [kg/m
3
]
d = inside diameter of measuring tubes [m]
K...K2 = constants (depending on nominal diameter)
1)
To compute the pressure loss for gases, always use the formula for Re ≥ 2300.
DN d [m] K K1 K2
85.35
⋅ 10
–3
5.70 ⋅ 10
7
7.91 ⋅ 10
7
2.10 ⋅ 10
7
15 8.30 ⋅ 10
–3
7.62 ⋅ 10
6
1.73 ⋅ 10
7
2.13 ⋅ 10
6
25 12.00 ⋅ 10
–3
1.89 ⋅ 10
6
4.66 ⋅ 10
6
6.11 ⋅ 10
5
40 17.60 ⋅ 10
–3
4.42 ⋅ 10
5
1.35 ⋅ 10
6
1.38 ⋅ 10
5
50 26.00 ⋅ 10
–3
8.54 ⋅ 10
4
4.02 ⋅ 10
5
2.31 ⋅ 10
4
Re
2m
·
⋅
π
d υρ⋅⋅⋅
---------------------------=
∆
p
K
υ
0.25
m
·
1.85
ρ
0.86–
⋅⋅ ⋅
=
∆
pK1υ m
·
K2 υ⋅
0.25
m
·
2
⋅
ρ
-------------------------------------+⋅⋅=
m
·
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