Endress+Hauser Proline Promass 84 MODBUS RS485 Operating Instructions Manual page 108

Technical data
Pressure loss (SI units)
108
Pressure loss depends on the properties of the fluid and on its flow.
The following formulas can be used to approximately calculate the pressure loss:
Pressure loss
formulars for
g
2 ·
Reynolds
Re =
p n r
· d · ·
number
D n
0.25
p = K · ·
Promass F DN 250
Re ≥ 2300
1)
Dp =
K · 1- a +
Dp = K1 · n
g
·
Re < 2300
Δp = pressure loss [mbar]
ν = kinematic viscosity [m2/s]
K...K2 = constants (depending on nominal diameter)
a = 0.3
To compute the pressure loss for gases, always use the formula for Re ≥ 2300.
1)
Promass
F, M
r
1.85 –0.86
g
·
a
n
0.25 1.85
g
· · ·
n
–6
b · ( – 10 )
e
n
0.25 2
K2 · · g
+
r
Proline Promass 84 MODBUS RS485
Promass
A
g
4 ·
Re =
p n r
· d · ·
a0004623
D n g
0.25 1.75
p = K · · ·
a0004626
r
–0.86
a0004626
D n · g
p = K1 ·
a0004628
g = mass flow [kg/s]
ρ = fluid density [kg/m3]
d = inside diameter of measuring tubes [m]
b = 91000
Endress+Hauser
a0003381
r
–0.75
a0003380
a0003379