PHOTON USE p p10 up z gr z 1 gr out x 1 gr out x 4 vec x 1 sh vec x 3 sh msg Velocity vectors at time step=10 msg Press RETURN to continue pause cont h1 x 1 fil;0.001 cont h1 x 3 fil;0.001 msg Temperature contours at time step=10 msg Press RETURN to continue pause p p20 up z gr z 1 gr out x 1 gr out x 4 vec x 1 sh vec x 3 sh msg Velocity vectors at time step=20 msg Press RETURN to continue pause cont h1 x 1 fil;0.001 cont h1 x 3 fil;0.001 msg Temperature contours at time step=20 msg Press RETURN to continue pause p p30 up z gr z 1 gr out x 1 gr out x 4 vec x 1 sh vec x 3 sh msg Velocity vectors at time step=30 msg Press RETURN to continue pause cont h1 x 1 fil;0.001 cont h1 x 3 fil;0.001 msg Temperature contours at time step=30 msg Press RETURN to continue pause p p40 up z gr z 1 gr out x 1 gr out x 4 vec x 1 sh vec x 3 sh msg Velocity vectors at time step=40 msg Press RETURN to continue pause cont h1 x 1 fil;0.001 cont h1 x 3 fil;0.001 msg Temperature contours at time step=40 msg Press RETURN to continue pause p p50 up z gr z 1 gr out x 1 gr out x 4 vec x 1 sh vec x 3 sh msg Velocity vectors at time step=50 msg Press RETURN to continue pause cont h1 x 1 fil;0.001 cont h1 x 3 fil;0.001 msg Temperature contours at time step=50 msg Press e to END ENDUSE GROUP 1. Run title and other preliminaries TEXT(Two Stroke Loop Scavenge Cycle 3D TITLE mesg(PC486/50 time last reported as appx. 4.5 min DISPLAY This example considers a two-stroke engine with loop scavenging. It is an unsteady three-dimensional flow with mixing of hot and cold streams and with time-varying domain boundaries. The exhaust and intake processes take place through ports in the lower part of the cylinder wall which are progressively uncovered by the descending piston. The exhaust port opens first and the cylinder pressure falls due to both outflow and cylinder volume change. The inlet port opens soon afterwards and inflow begins when the cylinder pressure has fallen below the total pressure in the inlet port. The incoming cold gas displaces and partially mixes with the hot exhaust gas. The inlet port flow direction makes an angle of 30 deg. to both the radial and horizontal directions. A single expanding grid is used in the z-direction so that the cells representing the ports both expand and are uncovered. The patches representing the port cells are active over a range of time steps. ENDDIS INTEGER(ID1,ID2,ID3,KNZ1,KNZ2,KNZ3) REAL(RPS,PI ,A1,AN,ANGLE,DEGS,VOLF) PI=3.14159 GROUP 2. Transience; time-step specification STEADY=F ** Revolutions per second. RPS=40. ** mean vol flowrate VOLF=0.8E-3*RPS ** Exhaust port opens at 70 deg BBDC. A1=-70. ** End of simulation 1 deg. ABDC AN=30. ANGLE=AN - A1 DEGS=RPS*360. TFIRST=A1/DEGS TLAST=AN/DEGS LSTEP=50 TFRAC(1)=-80. ** 2-degree steps TFRAC(2)= 2./ANGLE GROUP 3. X-direction grid specification CARTES=F;NX=4 ** Edges of exhaust and transfer ports at x-cell boundaries. XFRAC(1)=0.3;XFRAC(2)=0.5;XFRAC(3)=0.7;XFRAC(4)=1. XULAST=PI GROUP 4. Y-direction grid specification NY=4 YFRAC(1)=0.5;YFRAC(2)=.8;YFRAC(3)=.95;YFRAC(4)=1. ** Cylinder radius YVLAST=.05 GROUP 5. Z-direction grid specification ** Grid specified at BDC. NZ=10 GRDPWR(Z,NZ,.1111,-1.532) GROUP 7. Variables stored, solved & named SOLVE(P1,U1,V1,W1,H1);SOLUTN(P1,Y,Y,Y,N,N,N);STORE(RHO1) GROUP 9. Properties of the medium (or media) ENUL=1.E-5;ENUT=1.E-3 ** Temperature from enthalpy field. TMP1=LINH ** Set reciprocal of the specific heat... TMP1B=1.E-3 ; CP1 = 1.0/tmp1b ** Perfect gas law. RHO1=IDEALGAS DRH1DP=IDEALGAS ** Gas Constant m/R RHO1B=29./8305.6 GROUP 11. Initialization of variable or porosity fields FIINIT(P1)=3.0E5;FIINIT(H1)=9.0E5 GROUP 13. Boundary conditions and special sources ** Cylinder Head WALL (HEAD,LOW,1,NX,1,NY,1,1,1,LSTEP) ** Cylinder Wall WALL (CYL,NORTH,1,NX,NY,NY,1,NZ,1,LSTEP) ** Piston Crown WALL (PCR,HIGH,1,NX,1,NY,NZ,NZ,1,LSTEP) ** Exhaust port; atmospheric back pressure. PATCH(EXH1,NORTH,1,1,NY,NY,NZ,NZ,1,70) COVAL(EXH1,P1,1000.,1.0E5) COVAL(EXH1,U1,ONLYMS,0.0) COVAL(EXH1,V1,ONLYMS,0.0) COVAL(EXH1,W1,ONLYMS,0.0) COVAL(EXH1,H1,ONLYMS,SAME) KNZ1=NZ-1 PATCH(EXH2,NORTH,1,1,NY,NY,KNZ1,KNZ1,3,67) COVAL(EXH2,P1,1000.,1.0E5) COVAL(EXH2,U1,ONLYMS,0.0) COVAL(EXH2,V1,ONLYMS,0.0) COVAL(EXH2,W1,ONLYMS,0.0) COVAL(EXH2,H1,ONLYMS,SAME) KNZ2=NZ-2 PATCH(EXH3,NORTH,1,1,NY,NY,KNZ2,KNZ2,7,63) COVAL(EXH3,P1,1000.,1.0E5) COVAL(EXH3,U1,ONLYMS,0.0) COVAL(EXH3,V1,ONLYMS,0.0) COVAL(EXH3,W1,ONLYMS,0.0) COVAL(EXH3,H1,ONLYMS,SAME) KNZ3=NZ-3 PATCH(EXH4,NORTH,1,1,NY,NY,KNZ3,KNZ3,14,56) COVAL(EXH4,P1,1000.,1.0E5) COVAL(EXH4,U1,ONLYMS,0.0) COVAL(EXH4,V1,ONLYMS,0.0) COVAL(EXH4,W1,ONLYMS,0.0) COVAL(EXH4,H1,ONLYMS,SAME) ** Transfer port; patch TRA1-TRA3 PATCH(TRA1,NORTH,3,3,NY,NY,NZ,NZ,8,62) COVAL(TRA1,P1,-3.14,1.4E5) COVAL(TRA1,U1,ONLYMS,80.) COVAL(TRA1,V1,ONLYMS,-140.) COVAL(TRA1,W1,ONLYMS,-80.) COVAL(TRA1,H1,ONLYMS,300000.) PATCH(TRA2,NORTH,3,3,NY,NY,KNZ1,KNZ1,12,58) COVAL(TRA2,P1,-3.14,1.4E5) COVAL(TRA2,U1,ONLYMS,80.) COVAL(TRA2,V1,ONLYMS,-140.) COVAL(TRA2,W1,ONLYMS,-80.) COVAL(TRA2,H1,ONLYMS,300000.) PATCH(TRA3,NORTH,3,3,NY,NY,KNZ2,KNZ2,17,53) COVAL(TRA3,P1,-3.14,1.4E5) COVAL(TRA3,U1,ONLYMS,80.) COVAL(TRA3,V1,ONLYMS,-140.) COVAL(TRA3,W1,ONLYMS,-80.) COVAL(TRA3,H1,ONLYMS,300000.) GROUP 15. Termination of sweeps LSWEEP=10 RESREF(P1)=2.0E-4*VOLF RESREF(W1)=0.2*RPS*RESREF(P1) RESREF(U1)=RESREF(W1);RESREF(V1)=RESREF(W1) RESREF(H1)=RESREF(P1)*300000. GROUP 16. Termination of iterations LITER(P1)=10;LITER(U1)=1;LITER(V1)=1;LITER(W1)=1;LITER(H1)=5 GROUP 17. Under-relaxation devices RELAX(V1,FALSDT,5.E-3) RELAX(W1,FALSDT,5.E-3) RELAX(U1,FALSDT,5.E-3) GROUP 18. Limits on variables or increments to them VARMIN(P1)=1.E4 GROUP 19. Special calls from EARTH to GROUND ** Specification of moving grid for reciprocating engine. W1AD=ZMOVE IZW1=10 ** Angular velocity AZW1=RPS*PI*2. ** Crank radius BZW1=.050 ** Conrod centre distance/crank radius CZW1=4. SPEDAT(SET,GXMONI,TRANSIENT,L,F) GROUP 22. Spot-value print-out NPRMON=100 IXMON=2;IYMON=3;IZMON=8 GROUP 23. Field print-out and plot control NYPRIN=NY/5;NZPRIN=NZ/5;NPRINT=LSWEEP;NTPRIN=5 XZPR=T;IYPRF=NY;IYPRL=NY IPLTL=LSWEEP PATCH(RVEL,PROFIL,1,4,3,3,9,9,1,LSTEP) PLOT(RVEL,U1,0.0,0.0) PATCH(YZ,CONTUR,1,1,1,4,1,10,1,LSTEP) PLOT(YZ,H1,0.,20.0) PATCH(TIMPLOT,PROFIL,1,1,3,3,9,9,1,LSTEP) COVAL(TIMPLOT,P1,0.0,0.0);COVAL(TIMPLOT,H1,0.0,0.0) ***actdem*** idispa=10;csg1=p tstswp=-1