Simulation settings for Water
By placing the Water Settings component, you can define the simulation settings for Water. All components in the Water component library have Water simulation settings parameter. You need to specify which Water Settings component is assigned with the parameter by name.
For example, if you place this Water Settings in the model workspace, the name WaterSettings1 is assigned to it as default. Then, after placing Water.Basic.WaterVolume, you need to check the value of Water simulation settings. As default, the value is WaterSettings1, so the simulation settings is defined by WaterSettings1. If you want to change the associated Water Setting component, you can specify it by name.
This framework allows you to define and change the simulation settings for multiple components simultaneously.
Fidelity of properties
Three types of fidelity can be used in the current version of the Heat Transfer Library. There is a trade-off between the capability of the physical phenomena expression and the simulation cost. Thus, you need to specify it with your purpose of simulation.
If you use this mode, the properties is assigned with the following constants.
Specific heat capacity at the constant pressure c__p Jkg⋅K :
Molar mass MM kgmol :
Gas constant R__gas Jkg⋅K :
(*) R is Universal gas constant, and the value is 8.3144598Jmol⋅K
Specific heat capacity at the constant volume c__v Jkg⋅K :
Dynamic viscosity μ Pa s :
Thermal conductivity k Wm⋅K :
And, the specific enthalpy hflow is calculated with the following equation, and which is called as Function__hflow :
(*) The offset value of specific enthalpy is defined to be the same value as the other types of property at 273.15[K] and 101325[Pa]
Liquid Water (Lookup table of IAPWS/IF97)
If you use this mode, the properties is assigned with the following equations and constants. And, Look Up Tables (LUT) are generated with IAPWS/IF97.
Specific enthalpy hflow Jkg :
And, Density ρ kgm3 :
If you use this mode, the properties is calculated with Modelica.Media.Water package which is about IAPWS/IF97.
To check the details of the package and view the original documentation, which includes author and copyright information, click here.
(*) Warning : This mode is only available with Static mode of Dynamics of mass in this current version.
Dynamics of mass
You can simulate model with Water components in Static mass flow mode and Dynamic mass flow mode. There is a trade-off between the capability of the physical phenomena expression and the simulation cost. Thus, you need to specify it with your purpose of simulation.
The following model is one of the simplest Water simulation model. At both sides of edge, there are Water.Boundaries.WaterBoundary components to define the boundary conditions. And, Water.Basic.WaterVolume is placed at the center of the model, which is for Mass and Energy conservation calculation. The last pieces are Water.Basic.WaterFlow which is placed at between WaterBoundary and WaterVolume. Pressure difference and Mass flow rate will be calculated in them.
With this model, the behavior of two mode is explained in below.
If you select Static mode, Mass flow rate will be defined with
Then, the pressure difference is calculated from
(*) In this library, you can select several functions, like Linear type and Darcy-Weisbach equation.
Finally, p1 is obtained from
Thus, Mass flow rate is defined by the boundary condition. And by using Water.Basic.WaterValve and Pump, you can control the value of it.
If you select Dynamic mode, the Mass flow rate condition mflow0 is not used. In Water.Basic.WaterVolume, Pressure will be calculated with Mass and Energy conservation law. So, the pressure difference is obtained from
Mass flow rate is calculated from
In this mode, the Mass flow rate is dynamically changed based on the pressure balance calculation.
 : McBride B.J., Zehe M.J., and Gordon S. (2002): NASA Glenn Coefficients for Calculating Thermodynamic Properties of Individual Species. NASA report TP-2002-211556
Liquid WaterLookup table of IAPWS /IF97
Select Fidelity of properties
Use constants for each property.
Liquid Water (Lookup table of IAPWS/IF97) :
Properties are calculated with Lookup tables which are
generated with IAPWS/IF97, and only for Liquid phase.
(Temperature range : from 273.16 K to 500 K)
(Pressure range : from 5000 Pa to 50 MPa)
IAPWS/IF97 standard :
Properties are calculated with IAPWS/IF97. Media.Water
in Modelica Standard Library is the same as
If you use this option, call the library for properties.
(*) This is only available with Static mode of Dynamics
of mass in this current version of library
Select Dynamics of Mass flow rate
Mass flow rate is static. Pressure drop are calculated at
at each elements of pressure losses.
Mass flow rate is calculated from pressure difference at
each elements of pressure losses.
Heat Transfer Library Overview
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