.AixLib.Fluid.FixedResistances.HydraulicResistance

Information

Overview

Simple model for a hydraulic resistance with the pressureloss modelled with the pressure loss factor zeta (ζ).

Concept

Values for pressure loss factor zeta can be easily found in tables.

The following equation represents the dependencies of m_flow(_nominal), dp(_nominal), zeta and the diameter (D).

Δp = 0.5*ζ*ρ*v*|v|

= 8*ζ/(π^2*D^4*ρ) * m_flow*|m_flow|

Since this a simplified approach to calculate/generate a pressure drop, there exist no distinction between laminar and turbulent flow regarding ζ-values.

The non-existance of a turbulent flow, the equation handling near zero as well as the different approach of being able to use tabled zeta values, mainly distinguish this model from AixLib.Fluid.FixedResistances.PressureDrop.

Example Results

AixLib.Fluid.FixedResistances.Examples.CompareFixedResistances

Revisions

• April 27, 2017  by Philipp Mehrfeld:
  Model acc. to IBPSA conventions. Take into account homotopyInit., linearization, from_dp.
• April 2016  by Peter Matthes:
  Improved formulation of flow equation according to issue #232.
• November 2014  by Marcus Fuchs:
  Changed model to use Annex 60 base class
• November 1, 2013  by Ana Constantin:
  Implemented