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joshzrr December 10, 2009 20:58

A simple problem with mfix
 
1 Attachment(s)
Hello:
First of all, thank you for your time.
I used the MFIX (the stable one) make a simple test, just like the Fig in the attchments (geometry of vessel and array of numerical grids). It is a 2-D problem, there are two mass_inflow BC, one PO BC, for the wall NSW is adopted. One of the MI BC MIA is in the IC, the black area is define as NSW too.
But with the same install, TESTA cannot converge, but the TESTB can. I output the profile of velocity, both TESTA and TESTB, the value is different, it clear that TESTA is greater than TESTB, but with a similar tendency .
I do not know how to solve it, hope you can help me.
Looking forward to your reply!
Best regards!

PS: The input files MFIX. dat for TESTA is as follows:
! It is made available in MFIX documents
! Run-control section
RUN_NAME = 'des_fb1'
DESCRIPTION = 'fluid bed with single central jet'
RUN_TYPE ='NEW' ! 'RESTART_1'!
UNITS = 'cgs'
TIME = 0.0 !start time
TSTOP = 10.0
DT = 5E-4 !time step
DT_MAX = 1E-3
ENERGY_EQ = .FALSE. !do not solve energy eq
SPECIES_EQ = .FALSE. .FALSE. !do not solve species eq
MOMENTUM_X_EQ(1) = .FALSE.
MOMENTUM_Y_EQ(1) = .FALSE.
MOMENTUM_Z_EQ(1) = .FALSE.
! DT_FAC = 1.0
MAX_NIT = 250
TOL_RESID = 1.E-3
! Geometry Section
COORDINATES = 'cartesian'
XLENGTH = 3. !X length
IMAX = 3 !cells in i direction
YLENGTH = 5. !height
JMAX = 5 !cells in j direction
NO_K = .TRUE. !2D, no k direction
DZ(1) = 0.4d0 !Define DZ to be particle
!for 2D DEM cases
GRAVITY = 980
! Gas-phase Section
MU_g0 = 1.8E-4 !constant gas viscosity
RO_g0 = 1.205E-3 !constant gas density
! Solids-phase Section
RO_s = 2.7 !solids density
D_p0 = 0.4 !particle diameter
e = 0.9 !restitution coefficient
Phi = 30.0 !angle of internal friction
EP_star = 0.42 !void fraction at minimum
! fluidization
! Initial Conditions Section
! 1. bed
IC_X_w(1) = 0.0 !domain
IC_X_e(1) = 3.0 ! 0 < x < 15, 0 < y < 30
IC_Y_s(1) = 0.0
IC_Y_n(1) = 5.0
! initial values in the region
IC_EP_g(1) = 1.00 ! void fraction
IC_U_g(1) = 0.0 ! x-dir gas velocity
IC_V_g(1) = 0 ! y-dir gas velocity
IC_U_s(1,1) = 0.0
IC_V_s(1,1) = 0.0
IC_T_G(1) =273.
IC_T_S(1,1)=273
! Boundary Conditions Section
! 1. Central jet
BC_X_w(1) = 1.0 ! central jet
BC_X_e(1) = 2.0 ! 7 < x < 8, y = 0
BC_Y_s(1) = 0.0
BC_Y_n(1) = 0.0
BC_TYPE(1) = 'MI' !specified mass inflow
BC_EP_g(1) = 1.0
BC_U_g(1) = 0.0
BC_V_g(1) = 0 !inlet jet vel
BC_P_g(1) = 0.0
! 1. Secondary flow 1
BC_X_w(2) = 0.0
BC_X_e(2) = 1.0
BC_Y_s(2) = 0.0
BC_Y_n(2) = 0.0
BC_TYPE(2) = 'MI' !specified mass inflow
BC_EP_g(2) = 1.0
BC_U_g(2) = 0.0
BC_V_g(2) = 0.0
BC_P_g(2) = 0.0
! 1. Secondary flow 2
BC_X_w(3) = 2.0
BC_X_e(3) = 3.0
BC_Y_s(3) = 2.0
BC_Y_n(3) = 2.0
BC_TYPE(3) = 'MI' !specified mass inflow
BC_EP_g(3) = 1.0
BC_U_g(3) = 0.0
BC_V_g(3) = 0.0
BC_P_g(3) = 0.0
! 1. Secondary flow 2
BC_X_w(5) = 2.0
BC_X_e(5) = 3.0
BC_Y_s(5) = 0.0
BC_Y_n(5) = 2.0
BC_TYPE(5) = 'NSW' !specified mass inflow
! 2. Exit
BC_X_w(4) = 0.0 ! top exit
BC_X_e(4) = 3.0 ! 0 < x < 15, y = 90
BC_Y_s(4) = 5.0
BC_Y_n(4) = 5.0
BC_TYPE(4) = 'PO' !specified pressure outflow
BC_P_g(4) = 0.0
!
! DES INPUT
PARTICLES = 1 ! Number of particles
MN = 14 ! Maximum number of neighbors allowed per particle
KN = 800000 ! Normal inter-particle collision spring constant
KT = 800000 ! Tangential " " " "
ETA_DES_N = 18 ! Normal inter-particle damping coefficient
ETA_DES_T = 18 ! Tangential " " "
MEW = 0.2 ! Inter-particle friction coeffienct
KN_W = 1200000 ! Normal particle-wall collision spring constant
KT_W = 1200000 ! Tangential " " " "
ETA_N_W = 22 ! Normal particle-wall damping coefficient
ETA_T_W = 22 ! Tangential " " "
MEW_W = 0.1 ! Particle-wall friction coefficient
DES_NEIGHBOR_SEARCH = 2 ! Particle neighbor search method; 1=n-square; 2=quadtree; 3=octree
NEIGHBOR_SEARCH_N = 1
DTSOLID_FACTOR = 0.1D0
P_TIME = 10.0
! DES Logicals
DISCRETE_ELEMENT = .TRUE.
WALLDTSPLIT = .TRUE.
DES_CONTINUUM_COUPLED = .TRUE.
TSUJI_DRAG = .TRUE.
! End DES Input
! Output Control
!
OUT_DT = 0.05 !write text file BUB01.OUT
! every 0.1s
RES_DT = 0.01 !write binary restart file
! BUB01.RES every 0.01 s
NLOG = 25 !write logfile BUB01.LOG
!every 25 time steps
FULL_LOG = .TRUE. !display residuals on screen
!SPX_DT values determine how often SPx files are written. Here BUB01.SP1, which
!contains void fraction (EP_g), is written every 0.01 s, BUB01.SP2, which contains
! gas and solids pressure (P_g, P_star), is written every 0.1 s, and so forth.
!
! EP_g P_g U_g U_s ROP_s T_g X_g
! P_star V_g V_s T_s X_s Theta Scalar
! W_g W_s
SPX_DT = 0.01 0.01 0.01 0.1 100. 100. 100. 100.0 100. 100. 100.
! The decomposition in I, J, and K directions for a Distributed Memory Parallel machine
NODESI = 1 NODESJ = 1 NODESK = 1
! Sweep Direction
LEQ_SWEEP(1) = 'ISIS'
LEQ_SWEEP(2) = 'ISIS'
LEQ_SWEEP(3) = 'ISIS'
LEQ_SWEEP(4) = 'ISIS'
LEQ_SWEEP(5) = 'ISIS'
LEQ_SWEEP(6) = 'ISIS'
LEQ_SWEEP(7) = 'ISIS'
LEQ_SWEEP(8) = 'ISIS'
LEQ_SWEEP(9) = 'ISIS'

joshzrr December 14, 2009 20:37

Is anyting i can do?:confused:

mohsen0488 October 31, 2013 05:11

Dear joshzrr
i downloaded the MFIX files from MFIX site, and i read the readme.pdf but i don't know how to use the MFIX code in windows 7 64 bit .Fortran software is installed on my computer.
can you help me please to use MFIX code ?

Thanks a lot in advance.


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