KAPLEVENT
Русский ruEnglish enDeutsch deFrançais frEspañol esItaliano itPortuguês pt-BRTürkçe tr中文 zh-CNالعربية ar
Questionnaire

Pressure drop ΔP: how to read it and where the coefficient comes from

ΔP = ζ·ρ·v²/2: ζ from the data sheet of the specific model, referenced to a section

Pressure drop across the sectionA duct section with a mist eliminator: total pressure before the unit is higher, after — lower by ΔP; formula ΔP = ζ·ρ·v²/2.ΔP = ζ · ρ · v² / 2before the unitafter the unitζ — from the datasheet/source, not a typical value
The pressure before the assembly is higher, after it lower by ζ·ρ·v²/2

Short answer: the resistance of a mist eliminator is computed from ζ — the coefficient of the specific model referenced to a particular section: ΔP = ζ·ρ·v_ref²/2.

What to check in the ζ source

  • the section the ζ is referenced to (face or free);
  • the velocity/velocity range at which it was obtained;
  • the medium and temperature it applies to.

Typical mistakes

  • a “typical ζ” from a foreign model: ΔP is off by multiples;
  • transferring ζ to another velocity without accounting for v²;
  • mixing sections: v_ref from the face section while ζ is referenced to the free area.

Relation to energy impact

ΔP directly determines power: P ≈ Q·ΔP/η. The “Energy impact of ΔP” tool estimates it from your inputs.