.ModelicaTest.Fluid.BaseClasses.WallFrictionAndGravity

Information

This model describes pressure losses due to wall friction in a pipe and due to gravity. It is assumed that no mass or energy is stored in the pipe. Correlations of different complexity and validity can be selected via the replaceable package WallFriction (see parameter menu below). The details of the pipe wall friction model are described in the UsersGuide. Basically, different variants of the equation

dp = λ(Re,Δ)*(L/D)*ρ*v*|v|/2

are used, where the friction loss factor λ is shown in the next figure:

By default, the correlations are computed with media data at the actual time instant. In order to reduce non-linear equation systems, parameter use_nominal provides the option to compute the correlations with constant media values at the desired operating point. This might speed-up the simulation and/or might give a more robust simulation.

Contents

Name	Description
WallFriction	Characteristic of wall friction