modelHydraulicResistance
Extends from AixLib.Fluid.BaseClasses.PartialResistance.
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
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Real | zeta | Pressure loss factor for flow of port_a -> port_b | |
| Modelica.Units.SI.Diameter | diameter | Diameter of component | |
| Advanced | |||
| Modelica.Units.SI.PressureDifference | dp_start | 0 | Guess value of dp = port_a.p - port_b.p |
| Medium.MassFlowRate | m_flow_start | 0 | Guess value of m_flow = port_a.m_flow |
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