Constant volume chamber (TPF)#

The Constant volume chamber (TPF) block models the accumulation of mass and energy in a chamber containing a fixed volume of coolant.

Note

The user can specify from 1 to 4 input ports through which the coolant flows.

The volume of coolant can exchange heat with the heating network, for example, heat exchange with the environment through the heat port of the block.

The medium enters the chamber when the pressure in front of the inlet exceeds the pressure in the chamber, and exits when the pressure difference changes to the opposite.

It is assumed that the flow resistance between the inlet and the interior of the chamber is negligible. Therefore, the pressure inside the chamber is equal to the pressure at the inlet ports.

Similarly, the thermal resistance between the heat port and the inside of the chamber is negligible and the temperature inside is equal to the temperature at the heat port.

Mass Conservation Law (1) :

(1)#\[\dot m_1 + \dot m_2 + \dot m_3 + \dot m_4 + \epsilon= V \cdot (\frac{dp}{dt}(\frac{\delta \rho}{\delta p})_u + \frac{du}{dt}(\frac{\delta \rho}{\delta u})_p)\]

where:

\(\dot m_1, \dot m_2, \dot m_3, \dot m_4\) – mass flows through ports, [kg/s];

\(V\) – chamber volume, [m\(^3\)];

\(p\) – pressure, [Pa];

\( ho\) – density of the medium, [kg/m\(^3\)];

\(\epsilon=\frac{M-V/v}{ au}\) – correction that takes into account the numerical error in smoothing partial derivatives;

\(M\) – mass of the medium in the chamber, [kg];

\(v\) – specific volume of the medium in the chamber [m\(^3\)/kg];

\( au\) - phase transition time constant, [s];

\(u\) - specific internal energy, [J/kg].

Mass of the medium in the chamber (2) :

(2)#\[\dot m_1 + \dot m_2 + \dot m_3 + \dot m_4 = \frac{dM}{dt}\]

Law of conservation of energy (3) :

(3)#\[\phi_1 + \phi_2 + \phi_3 + \phi_4 +Q = \dot E\]

where:

\(\phi_1,\phi_2,\phi_3,\phi_4\) – потоки энергии через порты, [Вт];

\(Q\) – heat flow through the heat port, [W];

\(E=M\cdot u\) – total energy, [W].

Impulse balance

It is assumed that the pressure drop between the input ports and the internal volume of the chamber is negligible, so (4) :

(4)#\[p_1=p_2=p_3=p_4=p_K\]

where:

\(p_1,p_2,p_3,p_4\) – pressures on the corresponding ports, [Pa];

\(p_K\) – pressure in the chamber, [Pa].

1. Properties#

Property	Default Value	Description	Units of measurement
Chamber volume	0.01	-	m\(^3\)
Number of ports: 1; 2; 3; 4	1	-	-
Port 1 cross-sectional area	0.01	-	m\(^2\)
Port 2 cross-sectional area, available when `Number of ports` - `2`, `3` or `4`	0.01	-	m\(^2\)
Port 3 cross-sectional area, available when `Number of ports` - `3` or `4`	0.01	-	m\(^2\)
Port 4 cross-sectional area, available when `Number of ports` - `4`	0.01	-	m\(^2\)
Initial fluid energy specification: Temperature; Specific internal energy	Temperature	-	-
Initial chamber gauge pressure	0	-	Pa
Initial chamber specific internal energy, available when `Initial fluid energy specification` - `Specific internal energy`	83912.0	-	J/kg
Initial chamber temperature, available when `Initial fluid energy specification` - `Temperature`	20.0	-	°C
Phase change time constant	0.1	-	s

2. Inputs and outputs#

Parameters	Input/Output	Description	Units of measurement	Port type
Inlet 1	Input	The quantity is specified by the property `Number of ports`	-	Two-phase fluid
Heat port	Input	-	-	Heat exchange

In order to see the connection capabilities of the block, you need to go to page Description of block ports