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Conversion of pressure units



Conversion of volume units



Conversion of volume flow units

Pressure drop in a tube

The volume flow Q of a liquid with dynamic viscosity η in a tube with length L and inner diameter D causes a pressure drop Δp.

The pressure drop in laminar case is calculated as follows:


Calculation








m/s

Conversion

Formula: η = ρ ⋅ ν


mm²/s
g/ml
mPas

Viscosity

Dynamic viscosity η: 1 mPas = 1 cP (P = Poise)
Kinematic viscosity ν: 1 mm²/s = 1 cSt (St = Stokes)

Examples of viscosities

Liquid η [mPas]
water, liquid, 0 °C 1.79
water, 20 °C 1
water, 50 °C 0,55
water, 80 °C 0.36
water, liquid, 100 °C 0.28
Liquid η [mPas]
Acetone 0.36
Benzene 0.65
Ethanol 1.2
Methanol 0.58
Toluene 0.59