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PHOTON USE
AUTOPLOT
file
phi 5

da 1
au1
screen
msg gas velocity
pl 1
msg press  to continue
pause
cl
da 1
bu2
screen
msg liquid velocity
pl 1
msg press  to continue
pause
cl
da 1
liq
screen
msg liquid volume fraction
pl 1
msg press  to continue
pause
cl
da 1
screen
msg 'shadow' volume fraction of denser phase
pl 1
msg press e to END
enduse

NUMERICAL BENCHMARK PROBLEM 1.2   MONOPROPELLANT ROCKET
GROUP 1. Run title
TEXT(MONOPROPELLANT ROCKET :             W890
TITLE
DISPLAY
The problem considered is that of the injection of monopropellant
droplets through small holes in one end of a rocket motor. These
droplets burn (i.e undergo a phase change involving the dis-
appearance of high-density liquid and its replacement by low-
density gas), at a rate dependent upon the droplet diameter. As a
consequence, a pressure gradient is set up which accelerates the
gas and, to a lesser extent, the liquid. Friction between the
droplets and the gas causes the former at first to deccelerate
and later a accelerate.

The main task is to compute the distance from the injector at
which the propellant is fully consumed, as functions: of the
injection velocity, of the propellant and combustion-product
properties, and of a measure of the relative speed of momentum
and heat transfer.
ENDDIS
The GX-subroutine GXDROP is used for this case.

Locally-defined parameters:

FLOW       mass flow rate at the inlet
VELIN      inlet velocity
XLEN       the length of the rocket motor
CHATIM     relaxation factor

REAL(FLOW,VELIN,XLEN,CHATIM)
FLOW=1.E3;VELIN=50.0;XLEN=1.0
CHATIM=XLEN/VELIN
GROUP 3. X-direction grid specification
GRDPWR(X,100,XLEN,1.0)
GROUP 7. Variables stored, solved & named
** Solve for one pressure, two velocities, the volume
fractions of the two phases and the "shadow" volume
fraction of the second (denser) phase.
ONEPHS=F;SOLVE(P1,U1,U2,R1,R2,RS)
SOLUTN(GAS,Y,N,N,N,N,N)
** Provide storage for inter-phase mass transfer.
STORE(MDOT,CFIP)
GROUP 8. Terms (in differential equations) & devices
** Cut off built-in sources and diffusion terms
TERMS(GAS,Y,Y,N,Y,Y,Y);TERMS(LIQ,Y,Y,N,Y,N,Y)
TERMS(BU2,Y,Y,N,Y,N,Y)

GROUP 9. Properties of the medium (or media)
RHO1=1.E1;RHO2=1.E4;PRESS0=1.E7
GROUP 10. Inter-phase-transfer processes and properties
** Set constant inter-phase friction factor and activate
the calculation of the inter-phase mass transfer by
CFIPS=GRND1;CFIPC=1.0E5;CMDOT=1.0
GROUP 11. Initialization of variable or porosity fields
FIINIT(AU1)=VELIN;FIINIT(BU2)=VELIN;FIINIT(MDOT)=0.01*FLOW
GROUP 13. Boundary conditions and special sources
** Inlet at west end
INLET(INLET,WEST,1,1,1,1,1,1,1,1)
VALUE(INLET,P2,FLOW);VALUE(INLET,BU2,VELIN)
** Outlet at east end
PATCH(OUTLET,CELL,NX,NX,1,1,1,1,1,1)
COVAL(OUTLET,P1,FIXP,0.0);COVAL(OUTLET,P2,FIXP*RHO2/RHO1,0.0)
COVAL(OUTLET,AU1,ONLYMS,0.0);COVAL(OUTLET,BU2,ONLYMS,0.0)
GROUP 15. Termination of sweeps
LSWEEP=200
GROUP 16. Termination of iterations
RESREF(P1)=1.E-8*FLOW/RHO1
RESREF(GAS)=RESREF(P1)*RHO1;RESREF(LIQ)=RESREF(P1)*RHO1
RESREF(AU1)=RESREF(GAS)*VELIN*1.E-3
RESREF(BU2)=RESREF(LIQ)*VELIN*1.E-3
GROUP 17. Under-relaxation devices
RELAX(AU1,FALSDT,CHATIM);RELAX(BU2,FALSDT,CHATIM)
GROUP 19. Data communicated by SATELLITE to GROUND
** PRTSIZ=T activates GXDROP
PRTSIZ=T
GROUP 21. Print-out of variables
OUTPUT(GAS,N,N,N,N,N,N);OUTPUT(MDOT,Y,Y,Y,Y,Y,Y)
GROUP 22. Spot-value print-out
TSTSWP=-1;IXMON=NX/2;NXPRIN=NX/20;UWATCH=T
GROUP 23. Field print-out and plot control
NPLT=1;ORSIZ=0.4;ITABL=1
PATCH(XPROFILE,PROFIL,1,NX,1,1,1,1,1,1)