modelDynamicPipe

A simple dynamic pipe with heating/cooling

Information

This is probably the simplest model of a dynamic heated/cooled pipe.

The equations "on paper" are:

m_in = m_out

p_in - p_out = deltaP=K^.m_in|m_in|

dU/dt = m_{out^.h_out - m_{in^.h_in + Q}}

Representing the conservation of mass, momentum and energy where

U = m^.u is the internal energy

m is the mass of the fluid inside the pipe

u is the specific internal energy defined as c_{p^.T or h - p/rho}

The fluid is incompressible (constant density) and thus the mass balance is static.
The specific enthalpy of the fluid leaving the pipe is defined without considering the fluid velocity term.

Type	Name	Default	Description
Real	K	dp_nominal/m_flow_nominal^2	Pressure drop coefficient
Real	V	0.1	Volume of stored fluid [m3]
Real	rho	1000	Density of fluid — assumed constant for simplicity [kg/m3]
Nominal values
Real	dp_nominal	0.5	Nominal pressure drop [bar]
Real	m_flow_nominal	1	Nominal mass flow rate [kg/s]

Type	Name	Default	Description
Interfaces.FluidPort	port_a
Interfaces.FluidPort	port_b

Type	Name	Default	Description
Real	Q_flow	0	Heat flow rate into the pipe [kW]
Real	U		Internal energy [kJ]
Real	u		Specific internal energy — a fluid property [kJ/kg]
Real	m		Mass of stored fluid [kg]
Real	p		Pressure of fluid leaving the pipe [bar]
Real	h		Specific enthalpy of fluid leaving the pipe