Formulas for pressure drop calculations

also known as ΔP calculations

Formula:

calculate for each gas the density a given temperature and pressure:

Assuming that all volume percentages add up to 100%, the average density of a gas mixture can be written:

The gas viscosity of a mixture is calculated with the weights of its constituents ( and NOT with the volumes, as i.e.

The Reynolds number is a unit-less number that determines the flow regimes. With "v" gas velocity,

and "D" the diameter of the pipe:

Flow regimes:

LAMINAR: if the Reynolds number is smaller than 2073 the pressure drop follows as:

INTERMEDIATE ZONE: if the Reynolds number is between 2073 and 3520, the pressure drop calculates as:

TURBULENT : if the Reynolds number is larger than 3520, the pressure drop calculates as: