PROBLEM DEFINITION

This problem examines the flow of a two-phase mixture of Newtonian fluids within a sequence of chambers that is found in T-By pass distillation plates. The light phase is injected from holes located throughout the plate, while the dense phase is introduced from above. The mixing of the two phases, under certain conditions, produces a stable froth with high mass transfer rates. We are examining non-steady state flow. The geometry and initial/boundary conditions are illustrated below:

 

EXECUTABLE AND INPUT FILE

Input file (PROB.INP)

Windows 3.x/9x/ME/2000/NT Executable (PCTby.EXE)

Obtain both files in a compressed package (PCTby.ZIP)

 

 

SAMPLE RESULTS

Movies for dense phase

Volume fraction contours, for a 5 chamber simulation (movie).

Volume fraction contours, for a 2 chamber simulation (movie).

Volume fraction contours, for a 1 chamber simulation, low flow rate (movie).

Volume fraction contours, for a 1 chamber simulation, high flow rate (movie).

 

 

Pictures

Volume fraction contours for the dense phase at t=0.5s (generated using CONTOUR):

 

 

 

Velocity vector field for the dense phase at t=0.5s (generated using ARROW):

 

 

 

Velocity vector field for the light phase at t=0.5s (generated using ARROW):

 

 

 

 

 

Sample results input file (PROB.INP)

*

* ===[ PARAMETER'S FILE FOR TFLOW ; TRANSIENT T-PASS ]==

*

===[ PROBLEM PARAMETRES ]===============================================

Height of cavity, Angle of inclination against horiz. [HEIGHT,THETA]

0.025d0, 0d0

Gap length of liquid water, and two-phase exit (% of sides) [PINW,POUT]

25,25

Number of channels [NCH]

5

Lengths of each channel ("NCH" numbers) [WCH]

5*0.01

Gap length of air entry (% of sides) ("NCH" numbers) [PINA]

5*25

Internal (right) wall height for each channel ("NCH"-1 numbers) [HCH]

4*0.01

Inlet velocity of liquid water and air [UINW, UINA]

0.1,0.1

Initial volume fraction of liquid phase in cavity [R1INIT]

0.001

Interphase friction coefficient [FCOEF]

100d0

===[ GRID PARAMETERS ]==================================================

Number of cells in X- and Y- direction  [NI,NJ]

102, 32

===[ TIME PARAMETERS ]==================================================

Steady state flow ?  [STEADY]

.F.

Number of time steps  [NT]

500

Time step size  [DT]

0.01

===[ DEPENDENT VARIABLES ]==============================================

Solve for U- and P- equations ?  [INCALU]

.T.

Solve for R-equations ?  [INCALR]

.T.

===[ THERMO-PHYSICAL PROPERTIES ]=======================================

Material Density for both phases  [RHO1,RHO2]

1D3, 1D0

Laminar fluid viscosity for both phases  [VISC1,VISC2]

1D-3, 1d-5

===[ TERMINATION CRITERIA FOR ITERATIONS ]==============================

Maximum number of iterations per time step  [MAXIT]

500

Maximum acceptable value of residuals  [SORMAX]

5.D-05

===[ UNDER-RELAXATION ]=================================================

Under-relaxation factor for U- V- and P- equations  [URFU,URFV,URFP]

0.2D0, 0.2D0, 0.075D0

Under-relaxation factor for R-equation  [URFR]

0.9D0

False time step for U- and V- equations? [FALSDTU, FALSDTV]

.F., .F.

False time step size for U- and V- equations [DTFALSU, DTFALSV]

0.1D0, 0.1D0

Under-relaxation factor for DU- and DV- correction  [URFDU, URFDV]

1.0D0, 1.0d0

===[ COORDINATES OF FIXED PRESSURE POINT ]=============================

I,J index of location where pressure is fixed  [IPREF,JPREF]

2,2

===[ EQUATION SOLVER SELECTION ]========================================

Solver selection for U-, V- and P- equations [ISLVU,ISLVV,ISLVP]

2,2,2

Solver selection for R-equations [ISLVP]

2

Constant used by SIM solver  [ALPHA]

0.8D0

Weight terms of PP-equation with phase Density? [WEIGHT]

.t.

===[ TERMINATION CRITERIA FOR EQUATION SOLVER ]=========================

Number of line iterations for U-, V- and P- equations [LITERU,LITERV,LITERP]

3, 3, 3

Number of application of line iteration for R-equation  [LITERR]

2

===[ INPUT-OUTPUT PARAMETERS ]==========================================

I,J index of monitoring location  [IMON,JMON]

5,2

Iteration Index for residual and field printout  [NITRES,NITPRI]

100, 10000

Time Index for field printout  [NSTPRI]

1

Read IN initial field  [INREAD]

.T.

Name of restart file  [RSTFIL]

RESTART.

Copy OUT FINAL field  [INWRIT]

.T.

Name of SAVE file  [SAVFIL]

RESTART.

Name of main output file  [OUTFIL]

RUN.OUT