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| Technical focus: "double-pipe" heat exchanger |
Among the unit operations available in ProSimPlus (general steady state process simulation), the double-pipe heat exchanger module allows the user to determine the heat exchange and the pressure drop in the tube and in the annular space of a "double-pipe" heat exchanger. The calculation is made from its geometry and the characteristics of its input flows.
The configuration of the exchanger is made by defining its global parameters and by specifying the geometrical characteristics of the two constitutive elements (the inner pipe and the outer pipe). In order to keep the necessary flexibility to allow an accurate representation of any exchanger of this type, while preserving an intuitive and easy utilization of the module, particular attention was brought to the parameter input windows.
Calculations can be conducted for pure components and mixtures, with possibility of condensation or evaporation in the tube and in the annular space. They are based on the property model associated with each flow. For instance, a Water / HCL flow in the tube can use the Sour Water model while a pure water flow in the annular space uses a Pure Water model.
The user needs to choose the correlation that will be used to calculate the pressure drops in the tube and in the annular space. Many correlations are available (see below) that can be selected according to the type of flow (single-phase or two-phase), of regime (laminar or turbulent) and of wall (smooth or rough).
Similarly, calculation of thermal exchange coefficient in the tube and in the annular space uses different correlations according to the flow pattern and to the choices made by the user.
Results
At the end of the calculation, when the module has converged, the following results are available.
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Exchange area, |
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Exchanged heat |
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Clean and dirty exchange coefficients |
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Pressure drop on tube and on annular space sides |
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Streams characteristics: state, temperature, pressure, flow rate, enthalpy, viscosity, density… |
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Other fluids characteristics: dew and bubble temperature, uncondensable flow rate, velocity… |
Available correlations for the pressure drop calculation
| Single phase flow |
| Tube |
Annular space |
- Laminar regime:
o Poiseuille
- Turbulent regime, smooth wall:
o Blasius
o Herman
o Filonenko
o Karman-Nikuradze
- Turbulent regime, rough wall:
o Von Karman-Prandtl
o Colebrook-White
o Colebrook-White simplified
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- Laminar regime:
o Poiseuille modified Idel’Cik
- Turbulent regime, smooth wall:
o Blasius modified Idel’Cik
o Herman modified Idel’Cik
o Filonenko modified Idel’Cik
o Karman-Nikuradze modified Idel’Cik
- Turbulent regime, rough wall:
o Von Karman-Prandtl modified Idel’Cik
o Colebrook-White modified Idel’Cik
o Colebrook-White simplified modified Idel’Cik
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| Two phase flow |
| Tube |
Annular space |
- Flow pattern:
o Taitel (Horizontal)
o Taitel (Vertical)
o Kattan, Thome and Favrat
o Thome, El Hajal and Cavallini
- Mean vacuum ratio:
o Premoli
o Chisholm
o Homogeneous model
o Zuber and Findlay
o Zuber and Findlay (eau – vapeur)
o Rouhani and Axelsson
o Taitel and Duckler
- Pressure drop:
o Lockhart and Martinelli
o Baroczy
o Friedel
o Chisholm
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- Flow pattern:
o Taitel (Horizontal)
o Taitel (Vertical)
o Kattan, Thome and Favrat
o Thome, El Hajal and Cavallini
- Mean vacuum ratio:
o Premoli
o Chisholm
o Homogeneous model
o Zuber and Findlay
o Zuber and Findlay (eau – vapeur)
o Rouhani and Axelsson
o Taitel and Duckler
- Pressure drop:
o Lockhart and Martinelli
o Baroczy
o Friedel
o Chisholm
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Available correlations for thermal exchange coefficient calculation
| Single phase flow |
| Tube |
Annular space |
- Laminar regime, very short tube:
o Polhausen
- Laminar regime, short tube:
o Schlünder
o Hausen
o Sieder and Tate
- Turbulent regime :
o Dittus-Boelter
o McAdams
o Colburn
o Petukhov-Gnielinski
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- Laminar regime:
o Stephan
- Turbulent regime :
o Dittus-Boelter modified Stephan
o McAdams modified Stephan
o Colburn modified Stephan
o Petukhov-Gnielinski modified Stephan
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| Two phase flow (Tube or Annular space) |
- Dew case (tube or annular space side):
o Shah
o Liu and Winterton
o Steiner and Taborek
o Gungor and Winterton
o Kattan, Thome and Favrat
- Case of condensation (tube or annular space side):
o Pure fluid:
> Shah
> El Hajal, Thome and Cavallini
o Mixture:
> Silver, Bell and Ghaly
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