Flow resistance (TPF)#

The Flow resistance (TPF) block models the pressure drop in a section of a two-phase hydraulic network, based on specified nominal operating conditions.

Law of Conservation of Mass (1) :

(1)#\[\dot m_A + \dot m_B = 0\]

where:

\(\dot m_A\) – mass flow rate at the inlet, [kg/s];

\(\dot m_B\) – mass flow rate at the outlet, [kg/s].

Law of conservation of energy (2) :

(2)#\[\phi_A + \phi_B=0\]

where:

\(\phi_A\) - energy flow at the input, [W];

\(\phi_B\) - energy flow at the output, [W].

Pressure drop

The pressure drop is determined according to the following formula (3) :

(3)#\[\Delta p = C \cdot v \cdot \dot m \cdot \sqrt{\dot m^2 + \dot m^2_{кр}}\]

where:

\(\dot m\) – mass flow rate of the medium, [kg/s];

\(\dot m_{кр}\) – mass flow rate of transition to laminar flow regime, [kg/s];

\(\Delta p\) – pressure drop across the element, [Pa];

\(C\) – coefficient for calculating losses; (4)

\(S\) – flow cross-sectional area, [m\(^2\)];

\(v\) – specific volume, [m\(^3\)/kg].

(4)#\[C=\frac{\Delta p_{ном}}{v_{ном}\cdot \dot m^2_{ном}}\]

where:

\(\Delta p_{nom}\) nominal pressure drop, [Pa]

\(v_{nom}\) – nominal specific volume of the medium, [m\(^3\)/kg];

\(\dot m\) – nominal mass flow rate of the medium, [kg/s].

For the case where the specific volume can be considered constant, the user can write 0 in the Nominal specific volume field and then, C (5) :

(5)#\[C=\frac{\Delta p_{ном}}{\dot m^2_{ном}}\]

1. Properties#

Property	Default Value	Description	Units of measurement
Nominal pressure drop	0.002	-	MPa
Nominal mass flow rate	0.2	-	kg/s
Nominal specific volume	0.01	-	m\(^3\)/kg
Ports cross-sectional area	0.01	-	m\(^2\)
Fraction of nominal mass flow rate for laminar flow mode	0.001	-	-

2. Inputs and outputs#

Parameters	Input/Output	Description	Units of measurement	Port type
Input	Input	-	-	Two-phase fluid
Output	Output	-	-	Two-phase fluid

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