Encyclopaedia Index

CFIPS

a PIL variable, set in Group 10 of the Q1 file.

CFIPS determines how the reference coefficient for inter-phase transfer of momentum and other quantities, FRICCO, is to be calculated, for two-phase flows (i.e. when ONEPHS=F).

Then the transfer coefficient, Cphi, used for a particular dependent variable, e.g. velocity, or temperature, depends on the value of CINT for that variable

The FRICCO values are always calculated for the centres of those mass-continuity cells which are not filled by solid.

For momentum transfer:

The consequences of setting CFIPS to various values, which activate corresponding sequences in the open-source Fortran file GXIFRIC.HTM, are as follows:

If the shadow volume-fraction method is to be used to represent the burning, evaporation or condensation of particles, then the full-field variable RS should be attached to phase 1 via the TERMS command.

The drag-coefficient formulae

Details of these Cd correlations are given under the Encyclopaedia entry 'INTERPHASE DRAG MODELS'. The PIL-variable settings are:
CFIPD = 0. Standard drag curve ( default )
  = 1. Stokes-regime drag correlation
  = 2. Turbulent-regime drag correlation
  = 3. Subcritical-regime drag correlation
  = 4. Distorted-bubble "dirty-water" drag correlation
  = 5. Spherical-bubble "dirty-water" drag correlation
  = 6. Ellipsoidal-bubble "clean-water" drag correlation
  = 7. particle-fluidization drag model

Notes:

Storage of variables


STORE(CFIP) causes FRICCO to be stored.
STORE(SIZE) causes the particle diameter to be stored.
STORE(VREL) causes relspeed to be stored.
STORE(REYN) causes the particle Reynolds Number to be stored.
STORE(CD) causes Cd to be stored.
STORE(APRJ) causes storage of the projected area per unit
volume (not for CFIPD = 7.)
STORE(WEB) causes the Weber number to be stored if CFIPD=4.
or 5.
STORE(EOTV) causes the Eotvos number to be stored if CFIPD=6.

Further notes

Interphase mass transfer proceeds at the rate FRICCO * CMDOT, when the latter quantity is a positive constant.

See CINT, CMDOT, INTFRC and INTMDT for further information, and also the Encyclopaedia entry 'INTERPHASE DRAG MODELS'.

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