modelPipePressureLoss
Pipe generic pressure loss
Information
## Copyright © EDF 2002 - 2026
## ThermoSysPro Version 4.2
This component model is documented in Sect. 13.4 of the ThermoSysPro book.
# Pipe pressure loss
This component represents generic pressure losses in a pipe or a singularity using a single-friction pressure loss coefficient. It can also represent the pressure losses inside a circuit of connected pipes and singularities with a pressure loss coefficient equivalent to the whole circuit. The [lumped straight pipe](modelica://ThermoSysPro.WaterSteam.PressureLosses.LumpedStraightPipe) should be used instead to take that effect into account. For water/steam, the flow regime can be single-phase or homogeneous two-phase flow.
Following assumptions are made:
- The flow inside pressure losses is adiabatic. Non-adiabatic pipes must be
modeled by connecting pressure losses to volumes.
- The specific enthalpy inside the components is equal to the specific enthalpy at the inlet.
- The properties of the fluid are computed for the average pressure..
- Inertia due to momentum inside pipes is neglected.
The pipe pressure loss component is similar to the [singular pressure loss](modelica://ThermoSysPro.WaterSteam.PressureLosses.SingularPressureLoss), except that it enables the setting of inlet and outlet altitudes of the pipe.
## Modelica component model
The equations mentioned below are implemented in the component *PipePressureLoss*, located in the *WaterSteam.PressureLosses* sub-library.
This component has 2 connectors:
- C1: fluid inlet,
- C2: fluid outlet.
## Nomenclature
| Symbol| Description| Unit| Definition| Modelica name |
| :------------------------ | :---------------------------------------------------------- | :------------------------------- | :--------------------------------------------------------------- | :----------- |
| \\(g\\)| Gravity constant| \\(\mathrm{m} / \mathrm{s}^{2}\\)|| g |
| \\(h\\)| Fluid specific enthalpy | \\(\mathrm{J} / \mathrm{kg}\\)|| h |
| \\(m\\)| Fluid mass flow rate| \\(\mathrm{kg} / \mathrm{s}\\)|| Q |
| \\(P\_{\mathrm{i}}\\)| Fluid pressure at the inlet| \\(\mathrm{Pa}\\)|| C1.P |
| \\(P\_{\mathrm{o}}\\)| Fluid pressure at the outlet| \\(\mathrm{Pa}\\)|| C2.P |
| \\(z\_{\mathrm{i}}\\)| Inlet altitude| \\(\mathrm{m}\\)|| z1 |
| \\(z\_{0}\\)| Outlet altitude| \\(\mathrm{m}\\)|| z2 |
| \\(\Delta P\\)| Pressure loss of the fluid between the inlet and the outlet | \\(\mathrm{Pa}\\)| \\(P\_{\mathrm{i}}-P\_{\mathrm{o}}\\)| deltaP |
| \\(\Delta P\_{\mathrm{f}}\\) | Friction pressure loss between the inlet and the outlet| \\(\mathrm{Pa}\\)|| deltaPf |
| \\(\Delta P\_{\mathrm{g}}\\) | Gravity pressure loss between the inlet and the outlet| \\(\mathrm{Pa}\\)| \\(\rho \cdot g \cdot\left\(z\_{\mathrm{o}}-z\_{\mathrm{i}}\right\)\\) | deltaPg |
| \\(\Lambda\\)| Friction pressure loss coefficient| \\(\mathrm{m}^{-4}\\)|| K |
| \\(\rho\\)| Fluid density| \\(\mathrm{kg} / \mathrm{m}^{3}\\) || rho |
## Governing equations
### Static momentum balance equation
- Validity domain:
\\(\forall \dot{m}\\)
- Mathematical formulation:
$$\Delta P=\Delta P\_{\mathrm{f}}+\Delta P\_{\mathrm{g}}$$
- Comments:
In case of a singularity, \\(z\_{\mathrm{o}}=z\_{\mathrm{i}}\\) and consequently \\(\Delta P\_{\mathrm{g}}=0\\).
### Friction pressure losses
- Validity domain:
\\(\forall \dot{m}\\)
- Mathematical formulation:
$$\Delta P\_{\mathrm{f}}=\Lambda \cdot \frac{\dot{m} \cdot \lvert \dot{m} \rvert }{\rho}$$
- Comments:
The pressure loss coefficient \\(\Lambda\\) is provided by the user or can be obtained by inverse calculation from the mass flow rate.
## References
El Hefni, Baligh and Bouskela, Daniel (2019). [Modeling and Simulation of Thermal Power Plants with ThermoSysPro](https://link.springer.com/book/10.1007/978-3-030-05105-1), sect. 13.4. Springer Nature Switzerland AG.
Parameters
| Type | Name | Default | Description |
|---|
| Real | K | 10 | Friction pressure loss coefficient |
| Units.SI.Position | z1 | 0 | Inlet altitude |
| Units.SI.Position | z2 | 0 | Outlet altitude |
| Boolean | continuous_flow_reversal | false | true: continuous flow reversal - false: discontinuous flow reversal |
| Integer | fluid | 1 | 1: water/steam - 2: C3H3F5 |
| Units.SI.Density | p_rho | 0 | If > 0, fixed fluid density |
| Integer | mode | 0 | IF97 region. 1:liquid - 2:steam - 4:saturation line - 0:automatic |
Revisions
Author
Daniel Bouskela
