Thermal Fluid Two Port - MapleSim Help

Thermal Fluid Two Port

Define the base-equations shared by thermal-fluid two-port components

 Description A Thermal-Fluid Two-Port is the base model shared by many of the thermal-fluid components. It has two thermal-fluid ports, $a$ and $b$.

Equations

The following equations are the base equations for the two-port model. Each component based on this model extends these equations.

 Mass Balance Mass does not accumulate in the component. ${m}_{{\mathrm{flow}}_{a}}+{m}_{{\mathrm{flow}}_{b}}=0$
 Energy Balance The power flow into the device equals the rate of energy increase of the mass. If the mass is essentially zero, this is set to exactly zero. ${Q}_{\mathrm{flow}}+{H}_{{\mathrm{flow}}_{a}}+{H}_{{\mathrm{flow}}_{b}}=\left\{\begin{array}{cc}m{c}_{v}\stackrel{.}{T}& \mathrm{\epsilon }
 Enthalpy Flow The flow of enthalpy into each port depends on the direction of the mass flow through the component. ${H}_{{\mathrm{flow}}_{a}}={m}_{{\mathrm{flow}}_{a}}\left\{\begin{array}{cc}{h}_{a}& 0\le {m}_{{\mathrm{flow}}_{a}}\\ h\phantom{\rule[-0.0ex]{1.0ex}{0.0ex}}& \mathrm{otherwise}\end{array}$
 Temperature The temperature at a port is computed from the specific enthalpy at the port and the specific heat capacity of the medium. ${T}_{a}=\frac{{h}_{a}}{{c}_{p}}$ ${T}_{b}=\frac{{h}_{b}}{{c}_{p}}$ ${T}_{q}=T-\mathrm{sign}\left({V}_{\mathrm{flow}}\right)\left(1-{\mathrm{tap}}_{T}\right)\Delta T$ $\Delta T=\left\{\begin{array}{cc}T-{T}_{a}& 0\le {V}_{\mathrm{flow}}\\ {T}_{b}-T& \mathrm{otherwise}\end{array}$
 Volume Flow The volume flow is given by the mass-flow into port $a$  and the density of the medium. ${V}_{\mathrm{flow}}=\frac{{m}_{{\mathrm{flow}}_{a}}}{\mathrm{\rho }}$
 Pressure Drop The pressure drop from port $a$ to port $b$ is $\Delta p={p}_{a}-{p}_{b}$

Connections

 Name Description Modelica ID ${\mathrm{flowPort}}_{a}$ flowPort ${\mathrm{flowPort}}_{b}$ flowPort

Variables

 Name Units Description Modelica ID $\Delta p$ $\mathrm{Pa}$ Pressure drop from $a$ to $b$ dp ${p}_{x}$ $\mathrm{Pa}$ Pressure at port $x$ flowPort_x.p ${T}_{x}$ $K$ Temperature at port $x$ T_x $\Delta T$ $K$ Temperature increase of fluid, in direction of flow dT ${T}_{q}$ $K$ Temperature used for heat exchange with the ambient Tq ${Q}_{\mathrm{flow}}$ $W$ Heat exchange with ambient Q_flow ${V}_{\mathrm{flow}}$ $\frac{{m}^{3}}{s}$ Volume flow from from port $a$ to port $b$ V_flow $h$ $\frac{J}{\mathrm{kg}}$ Specific enthalpy of $\mathrm{medium}$ medium.h ${h}_{x}$ $\frac{J}{\mathrm{kg}}$ Specific enthalpy of flow at port $x$ flowPort_x.h ${H}_{{\mathrm{flow}}_{x}}$ $W$ Enthalpy flow rate into port $x$ flowPort_x.h $\mathrm{\rho }$ $\frac{\mathrm{kg}}{{m}^{3}}$ Density of $\mathrm{medium}$ medium.rho ${c}_{p}$ $\frac{J}{\mathrm{kg}K}$ Specific heat capacity of $\mathrm{medium}$ at constant pressure medium.cp ${c}_{v}$ $\frac{J}{\mathrm{kg}K}$ Specific heat capacity of $\mathrm{medium}$ at constant volume medium.cv

The symbol $x$ stands for  $a$ or $b$, it indicates one of the ports.

Parameters

 Name Default Units Description Modelica ID $\mathrm{medium}$ medium $m$ $1$ $\mathrm{kg}$ Mass of $\mathrm{medium}$ in component m ${T}_{0}$ $293.15$ $\mathrm{Pa}$ Pressure T0

Constants

 Name Default Units Description Modelica ID $\mathrm{\epsilon }$ $1·{10}^{-60}$ $1$ A very small number Modelica.Constants.small

 Modelica Standard Library The component described in this topic is from the Modelica Standard Library. To view the original documentation, which includes author and copyright information, click here.