This FMU models a fluid tank that is open to the atmosphere and whose fluid is completely mixed. The only energy exchange with the environment is through the fluid inlet and outlet. The model implements the following equations:
m * der(T) = inlet.m_flow * (inlet.T - T) (1) dp = inlet.p-outlet.p (2) outlet.m_flow = if noEvent(dp>0) then sqrt(dp/k) else -sqrt(-dp/k) (3) outlet.T = T (4) outlet.p = pAtm (5)where
inlet and outlet are the inlet and outlet ports,
m_flow is the mass flow rate,
T is the temperature and
p is the absolute pressure.
The parameters are
pAtm for the atmospheric pressure,
k for the flow coefficient and
T_start for the initial value of T.
Because the flow versus pressure drop equation (3)
is not regularized near zero flow, this model should not be
used around dp=0 if the model is combined
with a solver that requires the derivatives of the
model equations to be bounded.
This is for example the case if the model is used
within an algebraic loop that is solved using a Newton-Raphson
solver.