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-   -   Correction of KIVA ITAPE (http://www.cfd-online.com/Forums/main/11335-correction-kiva-itape.html)

hama May 2, 2006 03:44

Correction of KIVA ITAPE
 
HELLO:

I'am a new KIVA user I have KIVA 2, and ITAPE also,I want to improve this my ITAPE.

I already made a simple simulation of an internal combustion engine which functions to the natural gas (i.e. I assume that this fuel is100% of methane CH4).

I use the KIVA-II code to calculate the outputs to this simulation and I animate it with TECPLOT software.

According to the (fig 1,2 and3) I note that the flame didn't propagate from the spark plug toward the walls of the cylinder; therefore, the methane/air mixture didn't burn , where I didn't observe any absence of methane and the oxygen after the simulation.

My question is why the spark plug didn't produce a flame that it should be propagates itself on the whole mixture that exists in the combustion chamber.

Or my question with another way is - how I can I get a good propagation of the flame through a methane/air mixture in the combustion chamber-.

If anyone can send me ITAPE or OUTPUT, that'll be very helpful to me.

If anyone want detailles just send and I will do.

thanks

Engine specifications:

Bore 10.47 cm

Stroke =9.53 cm

Clearance=1.26 cm

Compression ratio=8.56

Chamber shape is a disk

RPM =2000 rpm

Fuel : methane (100% CH4)

Equivalent ratio 0.8969

Sparking location : central

ITAPE file:

t3aaa k053190 20x1x22 2-d baseline, w/qsou,chem3190

irest 0

ipost 1

nx 45

ny 1

nz 30

lwall 1

nchop 5

lpr 0

jsectr 1

irez 2

ncfilm 99999

nctap8 99999

nclast 99999

cafilm 45.

cafin 91.0

cadump 9.99e+9

dcadmp 9.99e+9

angmom 1.0

cyl 1.0

dy 0.0

pgssw 0.0

sampl 0.0

dti 1.0e-6

dtmxca 9.99e+9

dtmax 5.0e-5

tlimd 0.0

twfilm 9.99e+9

twfin 9.99e+9

fchsp 0.25

stroke 9.53

squish 1.26

rpm 2000.0

atdc -181.0

conrod 16.34

offset 0.0

swirl 0.0

swipro 0.00

thsect 0.5

epsy 1.0e-2

epsv 1.0e-3

epsp 1.0e-4

epst 1.0e-3

epsk 1.0e-3

epse 1.0e-3

gx 0.0

gy 0.0

gz 0.0

tcylwl 653.0

thead 653.0

tpistn 653.0

tvalve 653.0

tempi 350.0

pardon 0.0

a0 0.0

b0 1.0

anc4 0.05

adia 0.0

anu0 0.0

visrat-.66666667

tcut 700.0

tcute 1200.0

epschm 0.02

omgchm 1.0

tkei 0.3

tkesw 1.0

sgsl 0.0

uniscal 0.0

airmu1 1.457e-5

airmu2 110.0

airla1 252.0

airla2 200.0

expdif 0.2

prl 0.74

rpr 1.11

rprq 1.0

rpre 0.769231

rsc 1.11

xignit 6.0e+3

t1ign -1.425e-2

tdign 1.5e-2

ca1ign-10.0e+0

cadign 10.0

iignl1 1

iignr1 6

jignf1 1

jignd1 1

kignb1 2

kignt1 4

iignl2 0

iignr2 0

jignf2 0

jignd2 0

kignb2 0

kignt2 0

kwikeq 1

modmh 1

amh 10.0

bmh 0.5

cebu 1.

numnoz 0

numvel 0

injdist 0

kolide 0

t1inj 2.5e-2

tdinj 1.40e-3

ca1inj 95.0

cadinj 12.672

tspmas 0.0000

pulse 2.0

tnparc 0.00

rhop 0.0000

tpi 300.0

turb 1.0

breakup 0.0

evapp 0.0

npo 46

nunif 10

1 1 0.000 0.0

2 1 0.116 0.0

3 1 0.233 0.0

4 1 0.349 0.0

5 1 0.465 0.0

6 1 0.582 0.0

7 1 0.698 0.0

8 1 0.814 0.0

9 1 0.931 0.0

10 1 1.047 0.0

11 1 1.163 0.0

12 1 1.280 0.0

13 1 1.396 0.0

14 1 1.512 0.0

15 1 1.629 0.0

16 1 1.745 0.0

17 1 1.861 0.0

18 1 1.978 0.0

19 1 2.094 0.0

20 1 2.210 0.0

21 1 2.327 0.0

22 1 2.443 0.0

23 1 2.559 0.0

24 1 2.676 0.0

25 1 2.792 0.0

26 1 2.908 0.0

27 1 3.025 0.0

28 1 3.141 0.0

29 1 3.257 0.0

30 1 3.374 0.0

31 1 3.490 0.0

32 1 3.606 0.0

33 1 3.723 0.0

34 1 3.839 0.0

35 1 3.955 0.0

36 1 4.072 0.0

37 1 4.188 0.0

38 1 4.304 0.0

39 1 4.421 0.0

40 1 4.537 0.0

41 1 4.653 0.0

42 1 4.770 0.0

43 1 4.886 0.0

44 1 5.002 0.0

45 1 5.119 0.0

46 1 5.235 0.0

nho 0

square 0.0

rcornr 0.0

nstrt 0

icont 11101111011110000000011000

mirror 0

nvzone 0

nvvvec 0

nvpvec 0

nvcont 0

nsp 5

ch4 rho1 4.9653E-5

o2 rho2 1.9861E-4 mw2 32.000 htf2 0.0

n2 rho3 6.5344E-4 mw3 28.016 htf3 0.0

co2 rho4 0.0 mw4 44.011 htf4 -93.965

h2o rho5 0.0 mw5 18.016 htf5 -57.103

rtout 0.0

topout 0.0

botin 0.0

nrk 1

cf1 8.3000e5 ef1 1.5780e+4 zf1 0.0

cb1 0.0 eb1 0.0 zb1 0.0

am1 1 2 0 0 0

bm1 0 0 0 1 2

ae1 1.000 1.000 0.000 0.000 0.000

be1 0.000 0.000 0.000 0.000 0.000

nre 0

if you need to see my chem.f subroutine is:

subroutine chem c c ================================================== ==================== c c calculates the change in species densities and internal energy c due to kinetic chemical reactions c c chem is called by: kiva c c chem calls the following subroutines and functions: (none) c c ================================================== ==================== c

implicit double precision (a-h,o-z)

include 'cvmg.inc'

include 'common.inc'

dimension domega(lnrk)

double precision kf,kb c c <><><><><><><><><><><><><><><><><><><><><><><><><> <><><><><><><><><><> c

modmh=1

cebu=1.0

amh=4.

bmh=0.5 c

tchem=1.0d-10

do 100 k=1,nz

i4b=(k-1)*nxpnyp

do 90 j=1,ny

i4=i4b+(j-1)*nxp+1

do 80 i=1,nx

if(f(i4).eq.0.) go to 80

tijk=temp(i4)

if(tijk.lt.tcut) go to 80

rtijk=1./tijk c++ EBU

roijk=ro(i4)

rtturi4=cebu*eps(i4)/tke(i4) c++

do 70 ir=1,nrk

rp=1.

pp=1.

ne=nelem(ir)

do 20 kk=1,ne

isp=cm(kk,ir)

rom=spd(i4,isp)*rmw(isp)

if(am(isp,ir).eq.0) go to 10

if(rom.le.0.) rp=0.

if(rom.gt.0.) rp=rp*rom**ae(isp,ir)

10 if(bm(isp,ir).eq.0) go to 20

if(rom.le.0.) pp=0.

if(rom.gt.0.) pp=pp*rom**be(isp,ir)

20 continue

kb=0.

kf=0.

teback=1.

teford=1.

ekback=1.

ekford=1.

if(cb(ir).le.0.) go to 30 c +++ c +++ backward reaction coefficient c +++

if(eb(ir).ne.0.) ekback=dexp(-eb(ir)*rtijk)

if(zetab(ir).ne.0.) teback=tijk**zetab(ir)

kb=cb(ir)*teback*ekback

30 if(cf(ir).le.0.) go to 40 c +++ c +++ forward reaction coefficient c +++

if(ef(ir).ne.0.) ekford=dexp(-ef(ir)*rtijk)

if(zetaf(ir).ne.0.) teford=tijk**zetaf(ir)

kf=cf(ir)*teford*ekford c +++ c +++ Magnussen ebu model

if(modmh.eq.1) then

tauchm=mw(2)/(roijk*kf)

if(rtturi4*tauchm.lt.1.)then

kf=amh*rtturi4

rp=dmin1(spd(i4,1)/(am(1,1)*mw(1)),spd(i4,2)/(am(2,1)*mw(2)),

1 bmh*(spd(i4,4)+spd(i4,5))/(bm(4,1)*mw(4)+bm(5,1)*mw(5)))

endif

endif c +++ c +++ if any rate coefficients cannot be put in standard c +++ form, code them by hand and put them here c +++ c +++ find the reference species (the one in greatest danger c +++ of being driven negative) c +++

40 omeg=kf*rp-kb*pp

rmin=0.

if(omeg.le.1.d-30) go to 70

do 50 kk=1,ne

isp=cm(kk,ir)

if(spd(i4,isp).le.0.) go to 50

rom=omeg*fbmam(isp,ir)*mw(isp)/spd(i4,isp)

if(rom.ge.0.) go to 50

if(rom.lt.rmin) iref=isp

rmin=dmin1(rmin,rom)

50 continue

rom=spd(i4,iref)*rmw(iref)

flam=fam(iref,ir)

flbm=fbm(iref,ir)

ctop=flam*kb*pp + flbm*kf*rp

cbot=flam*kf*rp + flbm*kb*pp

domega(ir)=rom*dt*(ctop-cbot)/((rom+dt*cbot)*(flbm-flam))

do 60 isp=1,nsp

spd(i4,isp)=spd(i4,isp)+mw(isp)*fbmam(isp,ir)*dome ga(ir)

60 continue c

dechem=qr(ir)*domega(ir)/ro(i4)

dechk=dabs(dechem/sie(i4))

sie(i4)=sie(i4)+dechem

tchem=dmax1(tchem,dechk) c

civaomega(i4)=domega(ir)/dt c

70 continue

80 i4=i4+1

90 continue 100 continue

write(*,*)ncyc,tchem c +++ c +++ ignition -- single point, dual point, or ring c +++

if(t.lt.t1ign .or. t.gt.t2ign) return

diignl=dfloat(iignl(2))

nspark=cvmgzi(1,2,diignl)

do 140 n=1,nspark

do 130 k=kignb(n),kignt(n)

i4k=(k-1)*nxpnyp

do 120 j=jignf(n),jignd(n)

i4jk=i4k+(j-1)*nxp

do 110 i=iignl(n),iignr(n)

i4=i4jk+i

if(temp(i4).lt.1600.) sie(i4)=sie(i4)*(1.+xignit*dt) 110 continue 120 continue 130 continue 140 continue

return

end

Your help will be very helpful to me.


baltazar December 2, 2011 14:47

change in RSC and RPR
 
I think if you change in two parameters i.e. rsc (reciprocal schmidt number) and rpr (reciprocal prandtl number) for a case of apprpriate couple of these two values eventually combustion will occurs. Also energy released due to ignition and period of ignition should be appropriate. this request you to make try and error as experience of mine for simulation of a GDI engine by KIVA4


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