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Coagulation of carbon particles in premixed flames
1,./...I
(."urrenl work
on
nucleallon
131¢=decrease in size OI aer,~.sul parlicle.~ due It) evap~ral,)n i.~ oak ulaled Ior Iwo silUallOn~, in Ihe firsl, Ihe ant n~.saluraled wllh vapour so Ihal e.vaporal.~n is due In Ihe Kelvin elTecl and pr~.'N:eed,~al Ihe minimal ralc, in Ihe , ~ o r l d , Ihe air ns free from vapour and IIle rale ,d'evaporalion IS nra.ximal 'T'be *.'alculali¢~n,~are based upon an inlerpnlalion I'ormula covering Ihe Iranslllon wnlh decreasing parlicle size Irom diffusmn conlr4~l Iq~ flee m~decular tt¢~w It, organic o~ide aero~ls (d' controlled subraicronic dimensioa.~. By F ,JllltLE t, F L,rq ~,MTe,, H ML,Z.Z.AnEC~A, S J 'TEI;'HNE.R, A. 'T'HEVE.NE.'T'and P VERGNI)N,Inslilul de R~'herches sur la (",.ll;Jlyse ((" N r s ), Deparle menl de C'himie Physique, h~-Vdleurbanne, F'rame Mefalhc ~nde aerosols arc prepared hy decomposnli~m ~1 arihydr~u,~ c l'lh~rades =n Ihe dlfl'us, m flame (pl' a hydrq~gen~xvgen reaclor The flow rale ~d'lhechlonde vapour, Ihe lemperalure ol Ihe flame am'l Ihe residence lime ~1' Ihe reagenl in Ihe flame delerrnine Ihe shape (spherical or pc~lyhedral), Ihe dimensions (in Ihe range Irom 60 It~ 2(100 ~) and in ~ome case~ Ihe cryslalhne slruelure c~l' Ihe parllcle,,, which in all easc,~are ram. pl)rltuh 'T'hese highly divided o~ldes e~hlbll unusual phoh.)¢alal~'llC' pr~perlle,~ which are n~d enc'~urllered wllh aer~'~ls m lhe micron range or wllh porou,~ pa.rhcles prepared m a convenhonal way 'T'llanlum dl~xlde, in parlicular, enable,~ Ihe calalyll~: pholo n~ldal.~n (m Ihe u v range) al ror~m lemperalure ~d' ~rganic' and inorganic c~mp~)unds ParalT-in.s and ~lefirl,~ are ~xldlzed parhally and/or h~lally whereas ammnnla yields N~(.) arid N,,, carbon mon~xlde yleld,~ ~'arbon and hydrogen y~eld,~ :,ulphlde, ,~ulphur d . ~ l d e and ,~ulphur I%rm,~fio~ of'rio~ aerosol from Ihe combilion supporled reaction of FiCl~ 'and O~. By A P (Je~)e~.~e, R D ML~I~Le,Y and El R PLA~'e,,'T'0oxlde Inlernahonal, C'enlral Lab~ralories, Porlack Lane, ~h~ckh~n on'Tee% T'ee~ide, E,nglam'l 'Tbe h~rmal,m ol pa.rhculal¢ T l(.),~ ha,,, been ,sludied by Ihe uddlllorl ~1' small quanlllle,,~ (IO- ~-I(.)- ~ tool frachon) or 'TIC'I,~ v a l ~ u r hJ a lean C(') ~- O,, -I- N~ flame with a maximum Iemperalu.re o1' ahoul 144)l)"C Mea~u.remenls of 'T'ICI4 concenlrallon have been made as a rurlcllon ol' heighl (residence lime) by u v. absorphon spectro,~copy. 1"he re~ull,~ demon~lrale Ihal chemical reachon is ~ n l i a l l y cl~mplele ~iO m downslream ~1' Ihe C'O flame Ironl, al which ~lage Ihe 'TIC)~ parhcles have reached a dlameler o1"410 ,~. F"leclrorl mlcro~opic e~aminahon or ~amples ol malerlal Irom II1¢ flame shows Ihal parhcle ~ o w l h conhnues for a lurlher 2l~.1m by a floc~:ulallon m~'hanlsm '1"his is a malor laclor delermmmg Ihe final panicle slz~c (6]0 ,~) Agreemenl wllh Ibeorelleal fl~.~culalion predlcllons is reasonable bolh wllh re,peel Io Ihe deveh'~pmenl ol I he mean ~lze and Ihe .size distnbuhon Resulls ol smlenng expenmenls carried oul in Ihe flame and of ,similar me~.SLU'emenlsca.rned oul in Ih¢ hal stage o1' an eleclron mlcro.~ope demonstrale Ihal Ihe parllcles produced in Ihl,, syslem exhlb=l a fusion lemperalure much below Ihal ol" Ihe bulk .solid (18S0"C') The ~'currence of slnlering in Ihe flame is neces.',~uw Io accounl Ior Ihe I~'~rm ol Ihe 'T'lO,, parhcles produced in Ihls sysLem
(."oadeuution and evaporaliea of metallk" a ~ b . By E.' R BI~C'KLe.and K C' P(ffNION, Deparlmenl of M e l a l l u r w , 'The Llnlverslty, Sheh~eld SI "t.JD, England. 'The heal p u l ~ cloud chamber has been u.'~"d Io sludy Ihe c~.mden..sahonof melalhc aero.',ols in Ihe presence ol' purified argon. Mulhphcalion, growlh and ¢vaporallon ol Ca, Cd, Pb and Zn parhcles vary wllh Ihe backL,o'ound lemperalure in Ihe chamber 'The volallle C'd and Zn resemble Ihe alkah hahdes in Ihal ~ o w l h ~'~.'cur.~ readdy in suspension when a .~ul~clenl vapour pr¢.~ure is mainlained, and particles a~e formed Ihal ,selll¢ oul al appreciable speeds 'T'h~¢ parhcl¢~ fall from Ibe cloud independenlly Wilh Pb, Ihe vapour pres.,wre in Ih¢ vlcmlly ,'d Ihe melhng poinl is much lower, and nuclealion in Ih¢ vapour al the high lemperalures close In iLs poinl ol generahon is followed hy Ihe rapid arrcsl of ~ o w l h and cvaporahon as Ihe parhcles move away rain Ihe chamber 'This resulLs in Ihe I'rc-~zing in of large numbers ~1' mmule pa.rhclc% and a smoke i.s Iormed in which Ihere i~ hllle evidence of lurlher change When Ihe lempera lure o1' Ibe chamber I,~ reduced Io room lemperalure, Ihe pa.rhcle,s are exc~dingly line and numerous when firsl conden.~.d bul Ibe smuke Ihms oul, apparenlly by agglomerahon Observable mol,~n in Ihe .sm~~ke, apa.rl I'rom Ihe Brownlan mollorl, i,, dependenl on c~nv~'lion in Ihe supporhng ga~', Ihe parhL'lc.,, m~we by slreamlng and do nol rail oul (."oagala~on of carbon particle~ in premL~ed I]ame.q. By .I B H~,WARD, El. L. WtR~Br, R;.~ and (5 (? WIL/IAM,~, Fuels Research L,aboralnry, DepI ol C'hen'lical F'ngmccnng, Ma,~sachusells Inshlule o1' T'ec'hnology, C'ambndge, Mas.'~achu,~ell% IJ $ A 'The size dlslnbullon, number c~ncenlral.m, and I'rachon charged nf~.'arbon parll~.'le,,, al succe,~,,,ivestages ¢~1'N~rmahon in a law pr~sure I-lal flame were mea,~ured u,~lng m~decular beam ~ m p h n g , involving eleclncal beam deflecl.m and eleclron mlcn).~.opy ~d' beam ~lep~)slls and an npllcal ab.~orpllOn lechnlque Observed ~.'lusler lype ~lru¢lure witbJn roughly ,spherical pa.rhcl¢~ and d~'reasmg parhcle number corlcenlrah,'m Iollow Ing rapid nucleahon, indlcale Ihe parhcl~ do i n d ~ d coagulale dunng ~ o w l h Parhcle size and number concenlral,m dala c~nftrm Ihis concl,,siem, allhough Ihe expernmenlal coagulallon ralc e~.'ced~ by a lather or aboul I0 Ihe kmellc Ihei~ry colhsion rale approxlmalely adlusted I'or el~.'lrostahc I'l~rce~, based upon Ihe measured exlenl ol parhcle chargjng, arid Van der Waal,~ allrachon L"alculal,ms, based upton e~lrap~dal.m ~1' Ihe expernmenlal coagulahon rale conslanl rain Ih¢ flame re~on or sl~ificanl pusllc, le nuclealmn and ~,urlace rea~.'lmn, indlcale Ihat Ihe p',,u'hcle,~ nuclealed hrsl can ~r~w predominanlly by surtace ~.wr~wlh Io a volume mean dlame~r o1' aboul I(X) ,~ and Ihat Ihe number ol primary parhcl~ per ,~phcrncaJ unII wllhin Ihe I~nal chalnhke clu.slcr,~ is of order I(). 'Thus crvslalhle% Ibe number ol which i~ of order I0 ~ per ,~pherlcul unll, d¢~ nut reprt'senl Iormer parhcles
(."urrenl work
on
nucleallon
131¢=decrease in size OI aer,~.sul parlicle.~ due It) evap~ral,)n i.~ oak ulaled Ior Iwo silUallOn~, in Ihe firsl, Ihe ant n~.saluraled wllh vapour so Ihal e.vaporal.~n is due In Ihe Kelvin elTecl and pr~.'N:eed,~al Ihe minimal ralc, in Ihe , ~ o r l d , Ihe air ns free from vapour and IIle rale ,d'evaporalion IS nra.ximal 'T'be *.'alculali¢~n,~are based upon an inlerpnlalion I'ormula covering Ihe Iranslllon wnlh decreasing parlicle size Irom diffusmn conlr4~l Iq~ flee m~decular tt¢~w It, organic o~ide aero~ls (d' controlled subraicronic dimensioa.~. By F ,JllltLE t, F L,rq ~,MTe,, H ML,Z.Z.AnEC~A, S J 'TEI;'HNE.R, A. 'T'HEVE.NE.'T'and P VERGNI)N,Inslilul de R~'herches sur la (",.ll;Jlyse ((" N r s ), Deparle menl de C'himie Physique, h~-Vdleurbanne, F'rame Mefalhc ~nde aerosols arc prepared hy decomposnli~m ~1 arihydr~u,~ c l'lh~rades =n Ihe dlfl'us, m flame (pl' a hydrq~gen~xvgen reaclor The flow rale ~d'lhechlonde vapour, Ihe lemperalure ol Ihe flame am'l Ihe residence lime ~1' Ihe reagenl in Ihe flame delerrnine Ihe shape (spherical or pc~lyhedral), Ihe dimensions (in Ihe range Irom 60 It~ 2(100 ~) and in ~ome case~ Ihe cryslalhne slruelure c~l' Ihe parllcle,,, which in all easc,~are ram. pl)rltuh 'T'hese highly divided o~ldes e~hlbll unusual phoh.)¢alal~'llC' pr~perlle,~ which are n~d enc'~urllered wllh aer~'~ls m lhe micron range or wllh porou,~ pa.rhcles prepared m a convenhonal way 'T'llanlum dl~xlde, in parlicular, enable,~ Ihe calalyll~: pholo n~ldal.~n (m Ihe u v range) al ror~m lemperalure ~d' ~rganic' and inorganic c~mp~)unds ParalT-in.s and ~lefirl,~ are ~xldlzed parhally and/or h~lally whereas ammnnla yields N~(.) arid N,,, carbon mon~xlde yleld,~ ~'arbon and hydrogen y~eld,~ :,ulphlde, ,~ulphur d . ~ l d e and ,~ulphur I%rm,~fio~ of'rio~ aerosol from Ihe combilion supporled reaction of FiCl~ 'and O~. By A P (Je~)e~.~e, R D ML~I~Le,Y and El R PLA~'e,,'T'0oxlde Inlernahonal, C'enlral Lab~ralories, Porlack Lane, ~h~ckh~n on'Tee% T'ee~ide, E,nglam'l 'Tbe h~rmal,m ol pa.rhculal¢ T l(.),~ ha,,, been ,sludied by Ihe uddlllorl ~1' small quanlllle,,~ (IO- ~-I(.)- ~ tool frachon) or 'TIC'I,~ v a l ~ u r hJ a lean C(') ~- O,, -I- N~ flame with a maximum Iemperalu.re o1' ahoul 144)l)"C Mea~u.remenls of 'T'ICI4 concenlrallon have been made as a rurlcllon ol' heighl (residence lime) by u v. absorphon spectro,~copy. 1"he re~ull,~ demon~lrale Ihal chemical reachon is ~ n l i a l l y cl~mplele ~iO m downslream ~1' Ihe C'O flame Ironl, al which ~lage Ihe 'TIC)~ parhcles have reached a dlameler o1"410 ,~. F"leclrorl mlcro~opic e~aminahon or ~amples ol malerlal Irom II1¢ flame shows Ihal parhcle ~ o w l h conhnues for a lurlher 2l~.1m by a floc~:ulallon m~'hanlsm '1"his is a malor laclor delermmmg Ihe final panicle slz~c (6]0 ,~) Agreemenl wllh Ibeorelleal fl~.~culalion predlcllons is reasonable bolh wllh re,peel Io Ihe deveh'~pmenl ol I he mean ~lze and Ihe .size distnbuhon Resulls ol smlenng expenmenls carried oul in Ihe flame and of ,similar me~.SLU'emenlsca.rned oul in Ih¢ hal stage o1' an eleclron mlcro.~ope demonstrale Ihal Ihe parllcles produced in Ihl,, syslem exhlb=l a fusion lemperalure much below Ihal ol" Ihe bulk .solid (18S0"C') The ~'currence of slnlering in Ihe flame is neces.',~uw Io accounl Ior Ihe I~'~rm ol Ihe 'T'lO,, parhcles produced in Ihls sysLem
(."oadeuution and evaporaliea of metallk" a ~ b . By E.' R BI~C'KLe.and K C' P(ffNION, Deparlmenl of M e l a l l u r w , 'The Llnlverslty, Sheh~eld SI "t.JD, England. 'The heal p u l ~ cloud chamber has been u.'~"d Io sludy Ihe c~.mden..sahonof melalhc aero.',ols in Ihe presence ol' purified argon. Mulhphcalion, growlh and ¢vaporallon ol Ca, Cd, Pb and Zn parhcles vary wllh Ihe backL,o'ound lemperalure in Ihe chamber 'The volallle C'd and Zn resemble Ihe alkah hahdes in Ihal ~ o w l h ~'~.'cur.~ readdy in suspension when a .~ul~clenl vapour pr¢.~ure is mainlained, and particles a~e formed Ihal ,selll¢ oul al appreciable speeds 'T'h~¢ parhcl¢~ fall from Ibe cloud independenlly Wilh Pb, Ihe vapour pres.,wre in Ih¢ vlcmlly ,'d Ihe melhng poinl is much lower, and nuclealion in Ih¢ vapour al the high lemperalures close In iLs poinl ol generahon is followed hy Ihe rapid arrcsl of ~ o w l h and cvaporahon as Ihe parhcles move away rain Ihe chamber 'This resulLs in Ihe I'rc-~zing in of large numbers ~1' mmule pa.rhclc% and a smoke i.s Iormed in which Ihere i~ hllle evidence of lurlher change When Ihe lempera lure o1' Ibe chamber I,~ reduced Io room lemperalure, Ihe pa.rhcle,s are exc~dingly line and numerous when firsl conden.~.d bul Ibe smuke Ihms oul, apparenlly by agglomerahon Observable mol,~n in Ihe .sm~~ke, apa.rl I'rom Ihe Brownlan mollorl, i,, dependenl on c~nv~'lion in Ihe supporhng ga~', Ihe parhL'lc.,, m~we by slreamlng and do nol rail oul (."oagala~on of carbon particle~ in premL~ed I]ame.q. By .I B H~,WARD, El. L. WtR~Br, R;.~ and (5 (? WIL/IAM,~, Fuels Research L,aboralnry, DepI ol C'hen'lical F'ngmccnng, Ma,~sachusells Inshlule o1' T'ec'hnology, C'ambndge, Mas.'~achu,~ell% IJ $ A 'The size dlslnbullon, number c~ncenlral.m, and I'rachon charged nf~.'arbon parll~.'le,,, al succe,~,,,ivestages ¢~1'N~rmahon in a law pr~sure I-lal flame were mea,~ured u,~lng m~decular beam ~ m p h n g , involving eleclncal beam deflecl.m and eleclron mlcn).~.opy ~d' beam ~lep~)slls and an npllcal ab.~orpllOn lechnlque Observed ~.'lusler lype ~lru¢lure witbJn roughly ,spherical pa.rhcl¢~ and d~'reasmg parhcle number corlcenlrah,'m Iollow Ing rapid nucleahon, indlcale Ihe parhcl~ do i n d ~ d coagulale dunng ~ o w l h Parhcle size and number concenlral,m dala c~nftrm Ihis concl,,siem, allhough Ihe expernmenlal coagulallon ralc e~.'ced~ by a lather or aboul I0 Ihe kmellc Ihei~ry colhsion rale approxlmalely adlusted I'or el~.'lrostahc I'l~rce~, based upon Ihe measured exlenl ol parhcle chargjng, arid Van der Waal,~ allrachon L"alculal,ms, based upton e~lrap~dal.m ~1' Ihe expernmenlal coagulahon rale conslanl rain Ih¢ flame re~on or sl~ificanl pusllc, le nuclealmn and ~,urlace rea~.'lmn, indlcale Ihat Ihe p',,u'hcle,~ nuclealed hrsl can ~r~w predominanlly by surtace ~.wr~wlh Io a volume mean dlame~r o1' aboul I(X) ,~ and Ihat Ihe number ol primary parhcl~ per ,~phcrncaJ unII wllhin Ihe I~nal chalnhke clu.slcr,~ is of order I(). 'Thus crvslalhle% Ibe number ol which i~ of order I0 ~ per ,~pherlcul unll, d¢~ nut reprt'senl Iormer parhcles