CFD论坛 —双能量方程

For those interested in some code for scalar transport eqns under Fluent v5 here's

some examples. . . I developed this for solving heat transfer between fluid and a

packed bed solid (after a few weeks I moved to Fluent v4.5 which is better for this

application).

Anyway this should allow you to solve for solid phase temperature as a scalar

transport eqn as a special user porous media model assuming a packed bed of spheres.

I've cut down the code so it may or may not compile and I don't provide any

guarantees . . it may be more confusing than helpful!!!

SOLID_TEMP for local solid temperature. ZETA just stores the value, SOLID_TEMP

can be solved for. Another six UDS are required for other debug type results that I

found useful. So in total declare space for 8 UDS, but only solve for SOLID_TEMP -

turn off solution of all others. (with mods you can update ZETA due to reaction for

example) I would use the UDMI function in 5.4.8 for storing values at cells - but that

wasn't available until recently.

There are source terms for momentum - SRCE_Xmon etc. - these calculate the drag

due to the solid spheres on the fluid phase using the Ergun eqn. Link these into the

fluid domain sections in the Boundary Conditions panel.

There are source terms for energy - fluid and solid - this just calculates the interphase

You can use the init routine to help initialise the domain but will need mods

depending on what you try out. Then set some b/cs - note to set also your

SOLID_TEMP UDS b/c on each boundary - otherwise your solid temp will be 0

Kelvin which is not realistic!!!

Greg Perkins

ps: if you want to use a variable porosity use Fluent v4.5 - its toooo hard to implement

in Fluent v5.x

/**************************************************

**********************/ /* Reaction Module Source Code */ /* */ /* By Greg

Perkins */ /* CANCES, Australian Technology Park */ /* Ph: 02 9318 0004, Fax: 02

9319 2328 */ /* Email: perkinsg@cances.atp.com.au */ /* */ /* Started: 03-01-2000 */

/* */ /* Revisions: */ /* */ /* 14-02-2000

/**************************************************

/* ---- These routines implement a hetrogeneous reaction model for the

combustion and gasification reactions of carbon together with a

porous media model */

#include "udf.h" #include "sg.h"

/* ------------------------ REACTION MODEL DEFINES --------------------- */

#define PI 3.141592654 #define KJCAL 4.184 #define UNIVERSAL_GAS_CONST

8.314 /* -- [J/mol-K] */

#define SOLID_DENSITY(T) 1200 /* -- Coal material density [kg/m3] */ #define

3000.0*UNIVERSAL_GAS_CONST/12.0*(exp(1200/T)/pow((exp(1200/T)-1)*T/

#define alpha_s 0.5 /* -- fraction of energy released in solid phase */ #define alpha_f

0.5 /* -- fraction of energy released in fluid phase */

#define ZETA_CO 0.8 /* -- Initial coal vol. frac. */ #define ZETA_VO 0.2 /* -- Initial

#define ZETA_MAX 0.95 /* -- Maximum porosity without checks */ #define

DTHI_MAX -1.0e30

#define PERM_EXP_VOID 25.0 #define TEMP_KELVIN 0 #define TEMP_DEGC 1

#define TREF 273.0

/* -------------------- POROUS MEDIA MODEL DEFINES --------------------- */

/* ------------------------------------------------------------------------

a given cell in the domain.

1. CHECK IMPLEMENTATION

------------------------------------------------------------------------ */ void

Material_Properties(cell_t c, Thread *t, real *C1, real *C2) {

real zeta, zeta3, temp1;

zeta3 = pow(zeta,3.0);

temp1 = pow((1.0-((zeta-ZETA_VO)/ZETA_CO)),(1.0/3.0));