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一 一 一 一
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be added to t he ef f ect of gr ai n boundar y ener gy U nder t he st rai n bei ng mor e t han 4. 5%. gr owt h mode has c hanged to pol ycr yst al l i ne mode ( mar k ed b) ァロ) except i n s pec i mens pr e‑ anneal ed at 5500C a nd t hen i nser t ed at ext r a‑ l ow i nser t i ng vel oci t y.
It mi ght be c aus ed by an i ncr ease i n t he gener a‑
t i on f req uenc y of seed gr ai ns i n mat r i x st r uct ur e Gr ai n boundar y mi gr at i on ma y be gener al l y cx"
pr es s ed by t he rat e equat i on.
V = M X P. ・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・( 11
0 2 3
4 wher e M is t he boundar y mobi l i t y and P is t he 5t r ai n ( "! O)
Fi g. 8 Rel at i onshi p bet ween l og G ( = dS / dx at 50% si ngl e‑ cryst al l i zat i on) and strai n.
S: total l engt h of si ngl e‑ cryst al l i zed part per uni t wi dt h in t r ansver se di rect i on of speci men. x: d i st ance.
dr i vi ng f orce.
M is expect ed i n s ome wa y to depend on t he st r uct ur e of gr ai n boundar y. t emper at ur e and i m pur i t y l evel but not on t he dr i vi ng f orce. If t he mat r i x gr ai n s t r uct ur ε f or st r ai n anneal i ng pr oces s is qui t e st abl e， M ma y be const ant f or agi ven t emper at ur e. If so， V mus t depend on Pf o r hi gh pur i t y speci mens. Di s r egar di ng t he ef f ect s of i m‑ puri t i es， M a nd Par e gi ven by アt heequat i ons，
M 二 A e x p ( ‑ Q( () ) / k T) …. . . ・H ・..………...・H ・. . … … … … ・ー… … … . . . ・H ・. (2) P = ( Yb/ R) 十μ b2ムNd十(ムYs/t ) … … … . . . ・H ・. . . ……. . . ・H ・. . ……. . . ・H ・‑・・ ( 3) Her e T is t he absol ut e t emper at ur e， Q ( θ ) is t he act i vat i on ener gy f or gr ai n boundar y mi gr at i on dependi ng on t he mi sf i t angl e () ( or i ent at i on di f f er ence) of t he mov i ng boundar y， and A is cont ant bei ng i ndependent of t emper at ur e， Yb is t he gr ai n boundar y ener gy，μ is sheat modul us， b is Bur ger s' vect or of di sl ocat i on ムNdis di sl ocat i on densi t y di f f er ence bet ween gr owi ng si ngl e cr ys‑
tal and each mat r i x gr ai ns and al so Ys is sur f ace ener gy di f f er ence bet ween t hem. Thi r d t er m of ri ght hand si de i n Eq. ( 3) ma y be negl i gi bl e wh e n s pec i men t hi ckness tis r emar k abl y l ar ge as c om‑ par ed wi t h aver age mat r i x gr ai n si ze R. Or i ent at i on di f f er ences bet ween si ngl e cr yst al and mat r i x gr ai n ar e cons i der ed to be not so var i ed wi t h each mat r i x gr ai n， henc e V ma y be deci ded by P r at her t han M. F or t he pr esent s pec i mens， ，R μ ， b and tar e about 5 X 10‑5 m， 2. 5 X 1010 N/m2，
t he or de r of 3 X 10 ‑‑]0 m and 1. 2 X 10 ‑ 3 m， r espect i vel y. Aver age val ue o f gr ai n boundar y ener gy s houl d be appr oxi mat el y 2. 5 X 10 ‑ ] mJ /m 2守1] ) . If di sl ocat i on densi t y di f f er ence coul d be est i mat ed as 105and 2 X 106/ mm2 c or es pondi ng to st r ai n rat i o of 0 and 5% 11)， t hen val ues of V s houl d be 5. 2 X 102 X M and 9. 5 X 102 X M ( m/ s)， r espect i vel y. Compa r i ng t hese v争l ues wi t h t he upper
101
田頭孝介・増田正親・菊地千之
das hed l i ne i n Fi g. 9， M shoul d be cal cu l at ed as ＱＮ ＴｘＱＰｾＹ＠ m4/ J.s .
Dunn and Wal t er12) cal cul at ed M val ues f or hi gh. pur i t y al umi ni um on account of t he exper i ment al resul t s about nor mal gr ai n Ac c or di ng gr owt h by Bec k and Sper r yl 3)
to t hei r cal i cul at i on， M wa s 2X 10 ‑1 0 m 4/J . s f or t he st r ong mat r i x t ext ur e case， whi l e M wa s 2 X Ｑｏ ｾＹ＠ m4/J.s f or t he we a k mat r i x
刷訓叩叩瞬間州撒
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J ﹂ 一 ￨ 一 J 一
lE一
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l i q ‑ ‑ J K Z N 2 2 2 G e s t 4
一 一 一 J
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2一 一 一 一 / ・ っ ・ 一
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t ext ur e case. Thes e val ues ar e si mi l ar to t he above our val ues. T houg h t her e ar e sti l l r emai ned s ome quest i ons agai nst t he est i mat i on f or di sl ocat i on densi t y di f f er ence and ot her， gr ai n boundar y ener gy shoul d pl ay an i mpor t ant rol e f or t he dr i vi ng f orce of boundar y mi gr at i on as muc h as st rai n ener gy i n t he pr esent s peci mens
wa s al most s ame about 5 0 μ m whi c h is i ndeperト
sl ze gral l l mat r i x aver age T he
dent of pr e. anneal i ng t emper at ur e as men.
t i oned i n 3. 1. It is cur i ous t hat t he r ange of compl et e si ngl e cryst al mode hav e be.
c ome wi der as s hown i n Fi g. 9 wi t h pre.
anneal i ng t emper at ur e i n spi t e of si mi l ar mat r i x gr ai n si ze. But si ze of ( 100) gr ai ns whi c h have been r ar el y obs er ved i n pre.
anneal ed st r uct ur es are at l east t wi ce t he gr ai ns as de‑
me a n di amet er of mat r i x
scr i bed i n Fi g. 2 . O r i ent at i ons of t hese coar se mat r i x gr ai n wer e ascer t ai ned to be
明 一 / L T 丘一
￨ 寸 ﹁ . J J I B ‑ ‑ 一. ユ L
4 J 1 i 一 . 1 一 ﹂ l i ‑ ‑ 一
11一 つ⁝一 一.一 一一. 一一一 一一口 .m . 一一一 一一
↑ i o F L ￨ ↑ I L L ‑ ‑ L L L
al most near (1 00) [ 011J as aresu l t of accu rat e meas ur ement of mi cr o‑ or i ent at i on et ch宇
pi ts. If t he di sl ocat i on densi t y i n f i ne mat ‑ Fi g. 9 Gr owt h modes rel at ed to strai n and i nsert i ng‑
vel oci ty i nto the t emperat ure‑ gradi ent f urnace.
102
Grai n Growt h 01 Al umi ni um Sheets duri ng Strai n‑ Anneal i ng Process in Temperat ure‑ Gradi ent Furnace
ri x gr ai ns s houl d be s uppos ed to be hi gher t han i n coar se ones af t er l ow pl ast i c st rai n rati o. it ma y be under s t ood t hat onl y af ew ( 100) coar se gr ai n of l ow st rai n ener gy l evel wi l l be abl e to be g r own sel ect i vel y to si ngl e cr yst al by abs or bi ng ot her or i ent ed f i ne mat r i x grai ns̲ Agr eement on t he rel at i on of gr ai n si ze to st rai n rat i o bet ween t wo di f f erent ki nds of s ec ondar y heat t r eat ment coul d not be f ound so muc h
; : : ; 久 : パ : : ; ; ト J パ /バ イ イ ぺ 〆 /つ :¥ ¥ ¥ i
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¥ 1/ つ i
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Fi g. 10 I nverse pol e f i gures of gr own grai ns under the foJlowi ng pre‑
anneal i ng t emper at ur es and st rams.
(a) 4( Xt C. 2%. (b) 400oC. 3%. (d) 550oC. 3%. (e) 550oC. 5%. Lef t ; pl ane normal s.
Ri ght ; tensi l e di rect i ons
I n t he case of pr e‑ anneal i ng t emper at ur e at 550oC . hi gh qual i t y si ngl e cr yst al s hav e been g r own ev en under t he condi t i ons of hi gher st rai n rat i o of 5 to 7% and ext r a‑ l ow i nser t i ng vel oci t y (1. 88mm /h) . It s houl d be as s umed f r om t hese resul t s t hat di sl ocat i on densi t y i n mat r i x gr ai ns whi c h wer e j ust goi ng to be abs or bed by t he gr owi ng gr ai ns i n t emper at ur e‑ gr adi ent f ur nace mi ght bec ome l ower by no mea ns of r ecr yst al l i zat i on but r ecover y i n t he con‑
s equenc e of ext r a‑ l ow i nser t i ng vel oci t y. t hen coar se mat r i x gr ai ns whi c h ought to be essent i al l y act i vat ed to g r ow t hems el ves to pol ycr yst al l i ne mode mi ght hav e been g r own to si ngl e cr yst al mode by each cont ai nment phenomenon
Or i ent at i ons of g r own gr ai ns by st r ai n‑ anneal i ng ar e s hown i n Fi g. 10 f or sever al combi nat i ons of st rai n and i n‑ sert i昭 vel oci t y. Thes e ar e al most 町 ar ( 100) [ 011J havi ng no connect i on wi t h pr e‑ anneal i ng t emper at ur es and st r ai ns Thes e ( 100) or i ent ed gr ai ns mus t hav e been s ome of t he mat r i x gr ai ns and g r own pr ef er r enci al l y by abs or bi ng t he ot her or i ent ed mat r i x f i ne grai ns. But it is unexpl ai ned yet whet her t hi s phenomenon ma y be si mi l ar to t he case of ( 110) [ OOl J gr ai ns g r own dur i時 st rai n anneal i時 st age of F e ‑ 3. 25%S i al l oys or no. t Thes e ar e qui t e di f f erent f r om t he resul t s i n t he t emper at ur e‑ const ant f ur nace t hat or i ent at i ons hav e been muc h di sper sed f r om ( 100) [ Ol 1J w i t h t he i ncr ease of st rai n rat i o as ment i oned abov e par agr aph. It is' i nt er est i ng t hat cr yst al l ogr aphi c i ndi ces of mi gr at i ng di r ect i ons ar e l i mi t ed to町 ar [ Ol 1J. It is qui t e di f f erent f r om t he case of sol i di f i cat i on of al umi ni um i n whi c h gr owi ng di r ect i ons paral l el to c ol umner st r uct ur e ar e ( 100) 14) . On t he ot her hand. by st udi es on t he di r ect i onal sol i di f i cat i on of al umi ni um al l oys.
s uc h as A I ‑C u A
. I
AI ‑ Ab Ni etc. . gr owi ng di r ect i on wa s ge肘ral l y [ Ol 1J151 . 161 • and it is of t he 103ｆｆｊｾ ｦｉｊＧｊｬＮ ｦ
s a mc as t he di r ect i on of pr ef er r cd mi gr at i on i n t hc pr es cnt st r ai n‑ anneal i ng expcr i ence. But whc t hc r ε x ac t gr owt h me c ha ni s m of bot h cas es ar e si mi l ar or not ar e sti l l unk no wn
3. 4 Ef f ect s of St r ai n Rat i os a n d I mpur i t i es o n T e mpe r a t ur e at Gr o wing Fr ont of Si ngl e Cr ys t al
<...> 6 0 0
一
如
主
5 0 00 k
ｾ＠ 400
トζ
O
3 2 1 0 1 2 3 4 5 6 7 8 9 1 0
Di sf ance ( mm)
A s ment i oned i n t he abov e pa r agr aph ( 3. 3)， t he hi gher t he st r al l 1 r社tlO町 t hc l ower t he t emper at ur c at t he 1りcat i on of gr owi ng f r ont of si n耳lc cr yst al， t hat is. t he bOl l ndar y bet札印n g r owi ng si ngl e cr yst al and mal r i x gr ai ns. Besi cl es t he 日lOr phol oばy of t hese g r owi ng f r ont is not i n st r ai ght but i n zi g Fi g. 11 Temper at ur e di st ri but i on cur ve on the semi ‑ i nf i ni t e l engt h
spcci men in the t emper at ur e‑ gr adi ent f ur nace (in vaccuum) . z ag T he gr owi ng f ront posi t i ons of si ngl e cryst al s ar e s hown
T emper at ur e di st r i but i on by ar r ows f or eac h st r ai n f r om 0 to 4 %、 品l ong t he l ongi tl1cl i nal cl i rεct i on of s pec i men bei ng rcgarcl ccl as si mi ‑ i nf i ni t εl engt h is i ndi cat ecl i n Fi日11f or t hc pr esじnt t c mpc r at ur e gracl i cnt f ur nace (i n vac c uum) . Judgi n 日f r om bot h t he exper i ment al rcsl l l t s and t hi s fi耳l 1rc. actl l al t emper at ur c at gr owl n日f r ont ma y bc cst i matt:cl to bc 600， 585， 560， 515 and 49( f C f or t he spcci . me ns whi c h wc rじpr c. anncal t、cl al 55( f C ancl st r ai ned i n 0 l 2 3 and 4% r espect i vel y and t hen i nscr t ed i nt o t he fl1r nac e at t he vel oci t y of 10mm/ h. I n t he spcci l l l cns cl dor mecl i n l css t han I
% t he l ocat i ol l of gr owi ng f r ont wa s def i ned as a5 0 % si n gl e‑ cryst al l i zecl l ocat i on bec aus e of bci n耳
l l nabl e to mc as ur c accur at e l ocat i on cll1eto l hc exi st el l ce of ma n y un社bs or bedmat r i x記r a] [ ls T h c r ea日onwh y t he l ocat i on of gr owi n耳 目i ngl c cr yst昌1 f r onl in t hc t cmper al l l r c‑ gr adi c、nt fl l rl l a 仁じ
is s wi t c hc d to l ower t emper atl1re si cl e by st r ai n mi ght be c ons i der ed to bむduc to a日ll1cr cas e III
dr i vi n耳f or ce by st r ai n ener gy呂ndi nt εr昌ctl Ons bet ween i mpur i t y at oms and di sl ocat i on. It is wcl l k no wn l h昌t l mpl1nl y at oms 亡xi st i ng i n compol l ncl s s uc h as sl1l f i des， ni t ri des. carbi cl e，εtc.， ar e cf f ect i ve to di st l l rb t he r ec over y of bot h st r ai n ancl t hc gr ai n bOl l ncl ar y mi gr at i on. T hes e i mpur i t i e日
ar e usual l y df ect i ve to r ec over y and r ecr yst al l i zat i on onl y l1ncl er a cer t ai n l c mper al ur e as cl ar i fi ecl by Tagas hi r a et al.") ， t hat is t he s a me as cl i ssol vi ng t e mp亡ratl1rc of t hei r compouncl s . I n t he pr es ent al umi nil1m s pec i mens， ho we v己I ¥r es t r al nt t cnl per at ul むf or gr ai n 日r owt h cl ccreasecl wi t h st r a] [ l .
S o t he rol e of i mpur i t y at oms does not pl ay as c ompol1nds but pr obabl y as sol i d sol ut i ons. If l at t i ce di f fl1si on of i mpur i t y 抗o ms i n Al s uc h as じ11. Si， ma y be ai ded by uメi ng t hc di sl ocat i ons as
104
Crai n Cr owt h 01 Alllnlillillnl Sheets dl l ri ng Sl rai n‑ Anneal i n日PIυcess in Temperat l l rc‑ Gradi cnt Furnace
hi gh di f f l l Si vi t y pat hs̲ T he s e at ol l l s l l l ay be abl e to di f f l l se easi l y frOl l l l l l at ri x gr ai ns (lo we r t el l l perat l l re si cl c) to 日i ngl c cr ys t昌1 ( hi gher t el l l perat l l re si dε) ̲ Dl l r i ng t hi s pr ocess. i l l l pl l ri ty at ol l l s m江y st ay t Cl l l por乱l i l y al o日日 t he bOl l ndar y bet wc巳n si ngl e cr yst al a nd i ts adj acent l l l at ri x gr ai ns.
bl l t next i ns t ance t hey l l l ay be cl i ff日se i nt o si ngl c cr yst al as sl l bst i t l l t i onal at ol l l s b y l l l eans of vac anc i es t herl l l oeql l i l i bri l l l l l l y gener at ecl i nsi cl e t he si ngl c c r ys t aL Thl l S bOl l ndar y llli耳r atl Onl l l ay be pr omot ecl b y t he r el easc frol l l i l l l puri t y i nhi bi t i ons̲ It ShOl l l cl be mor e consi cl erecl i n det ai l s
4. Conc l us i on
T h e ef f ect s of pr c‑ anneal i n耳t Cl l l perat l l res. st r ai n r at i os a nd s pec i men i nser t i ng vel oci t i es i nt o t er nper at l l r e‑ gr acl i ent f l l r nace on t he s t r ai n‑ anneal i ng behavi Ol l r has been st l l di ed i n comr ner ci al pl l ri t y al l l mi ni l l日L T h e f ol l owi ng resl l l t s hav e been obt ai necl .
( ll g r owt h rnocl es ha¥icbc en cl ct errn i necl on t he cl i agrarn of st r ai n a nd s pec i men i nscr t i ng vel oci t y Ac c or c l i ng t o t hcsc cl i agrarns. l l pper cri t i cal vel oci t y f or si ngl e cr yst al r node has i ncr easecl wi t h a日i ncr cas c i n st rai n̲ It ma y be est i mat ecl t hat gr ai n bOl l ncl ar y ener gy ShOl l l cl pl ay an i m por t ant rol c f or t he dr i vi ng f or ce of bOl l ndar y mi gr at i on as rnl l ch as st r ai n ener gy
121 Or i ent at i ons of g r o wn gr ai ns by s t r ai n‑ anneal i ng ha v e been a l wa y s near ( 100) [ 011J bei ng no af f ect ed b y st r ai n a nd i nser t i ng vel oci t y̲ Whe r e a s i n t he resl l l t s of s t r ai n‑ anneal i ng i n t he t er nper at l l r e‑ const ant f ur nac c t hes e hav e bc en ml l ch di s per s ed f r om ( 100) [ 011J exc ept i ng l l n守
cl ef or mecl s pec i mens
( 3) A s t he pr e‑ anneal i口氏 t emper at l l r e wa s rai secl . t he concl i t i on f or si n耳le cr yst al g r owt h l l l ocl e
日pr eacl ed on t he s t r ai n‑ i ns c r t i ng vel oci t y di agr ar n̲ Af t er al l . f or pr eanneal i ng at hi gher t emper at l l r e Sl I1区lecr yst al s excl l l【l i ng a ny i sl and gr ai ns cOl l l d bc g r o wn ev en at r api d i nsert ‑ 1I1耳vel oci t y ill t hc rc日iOll of hi只her st r ai n a nd ext r a‑ l ow i nser t i ng vel oci t y
i4) Mo d e f or poor qual i t y si ngl e cr yst al s c ont ai ni ng l ot s of i sl and gr ai ns wa s obt ai necl uncl er t he concl i t i ons of l owr r st r ai n a nd hi ghc r i nser t i ng vel oci t y. whi l e bi ‑ cr yst al mo d e wa s gcner al l y done lIn d n hi gher st r ai n a nd l ower i nser t i ng vcl oci t y
i5 1 Bot h t he t c mpc r at nr c at t hc f r ont of g r owi ng si ngl e cr yst al ancl t he r nl l mber ()f r emai ned f i ne i sl ancl 日r ai ns wi t hi n si n日le cr yst al wc r e cl ecr eased by st rai n̲ It has not been obs c r v ed i n st r al I1‑a日n('社l i n日pr oc c s son F c ‑ :3. 2 5 %S i al l oy i ncl udi ng cer t ai n ki nds of i mpl l r i t i cs
Ac k nowl e dg e me nt s
T h e a¥lt hor s gr at e[ ul l y ac knowl c c l日c t he usef ul acl vi ces of Pr of日S日or H̲ Na k a e of t hc Hokkai c l o l1ni ver si t y at t he t i me a nd al so Pr of es s or K. I k a wa of Tohokl l l i ni vcr si t y
105
田頭孝介・増田正親・菊地千之
( Rec ei v ed 17t h Ma y . 1 9 8 5 ) R e f e r e n c e s
1) Aust . K. T. . Koch. E. F. and Nonk en， F. C. :Tr ans A I ME，215 (1952)， 180.
2) Fuj i i， T. :Ki nz oku (i n J apanese)， 55， No. 2 (1966) ， 9 . 3) Dunn， C. G. and No此en，G. C. :M et al s Pr ogr ess， 64 ( 1953)， 71.
4 ) Tagas hi r a， K. and Nak ae， H. :J. J apan I nst. of Met al s (i n J apanese)， 35 (1971) ， 683.
5) Nak ae， H. and Tagas hi r a， K. :Tr ans J I M ， 14 (1973)， 15.
6) Nak ae， H. and Tagas hi r a， K. Bul l et i n of t he Facul t y of Engi neer i ng， Hokkai do Uni ver si t y， No . 46， (1967)， 19.
7) Nak ae， H.， Tagashi r a. K. and Mat s umi dor i， T. :J. J apan I nst. of Met al s， 34 (1970)， 333.
8) T aok a， T.， Fur ubayas hi， E. and Takeuc hi， S. :J ap . J. A p pl. phys.， 4 (1 965) . 120.
9) Nak ae， H. and Y a ma mur a， H. :J. J apan I nst. of Met al s， 32 (1 968) . 130 10) Sugi mur a. O. and Ka ma da， M. :Tet s u to hagane (i n J apaness)， 58 (1972) . 452.
11) Tagas hi r a， K. :unpubl i shed d at a.
12) Dunn， C. G. and Wal t er . J. L. :Secandar y Rec ηstal l i z.αti an， Techni cal i nf or mat i on seri es of Gener al El ec tri c Lt d.， N e w Yor k ， (1965)， 25.
13) Beck. P. A. and Sper r y， P. R. :Tr ans. A I ME， 185 (1949) . 240.
14) f or exampl e， Barret t . C. and Massal ski， T. B.， :St r uct ur e ザ M e tαls( 3rd Ed. )， per gamon pr ess， (1980) ， 536.
15) Her t z bur g， R. W.， L emk ey， F. D. and For d. J. A. :Tr ans. A I ME， 233 (1965)， 342.
16) Kraf t . R. W. :Tr ans A I ME， 224 (1962)， 65.
17) f or exampl e， Mat s uok a， T. :Tet s u to Hagane， 53 ( 1967)， 1007
106
火炎の燃焼・熱伝達特性およびその構造の解明に関する研究( 第3 報，相似I噴流火炎に及ぼす燃焼室内の圧力の影響について)
火 炎 の 燃 焼 ・ 熱 伝 達 特 性 お よ び そ の 構 造 の 解 明 に 関 す る 研 究
(第
3 報 ， 相 似 噴 流 火 炎 に 及 ぼ す 燃 焼 室 内 の 圧 力 の 影 響 に つ い て )
開 山 政 良
A S tu d y o n t h e Cha r a c t e r is t ic o f C o mb u s tio n a n d He a t T r a n s fe r o f a F l a me
( 3 r d R e p o r t， T h e E f f ec t of t he A mb i e n t P r e s s u r e t o t he An a lo g ic J et F la me )
Ma s a y o s h i K o b iy a ma
Abs t r ac t
In thi s r epor t， t he ef f ect s of t he ambi ent pr essur e， t hat is t he pr essur e in t he combus t i on c hamber， on t he charact eri st i cs of t he j et f l ames wer e exami ned wi t h a ne w pr essur ed combus t i on c hamber to obser ve t he vari at i on of t he f l ame l engt h， t emper at ur e， combus t i on ef f i ci ency and so on. T he exper i ment wa s per f or med wi t h di f f usi on f l ames of ai r and pr opan gas f uel t hr ough asi m pl e gas bur ner poi nt ed upwar d and wi t h t he ex per i ment al condi t i ons set up to f or m t he anal ogi c j ets of whi c h charact eri st i cs wer e not af f ect ed by t he ambi ent pr essur e at t he i nl et 01 combus t i on chamber . T he exper i ment al resul t s of f l ame l engh and combut i on ef f i ci ency s how t hat t he r egi on of ai r and f uel vel oci t y rat i o is di vi ded i nto t wo t hat is ar egi on af f ect ed am bi ent pr essur e and di d not af f ect ed one
1 . 緒 昌
炭化水素系燃料の燃焼特性は，雰囲気正力により強く影響を受けることは良く知られている。
し か し ， 過 給 ボ イ ラ の よ う に 定 常 燃 焼 を 行 な い ， 火 炎 か ら の 熱 伝 達 を 積 極 的 に 利 用 す る 立 場 か ら の 研 究 は 少 な く ， 雰 問 気 圧 力 の 影 響 が 火 炎 の 特 性 に 及 ぼ す 影 響 を 系 統 的 に 調 べ て お く 必 要 が あ る 1，21加圧雰酔
i
気 下 に お け る 定 常 火 炎 の 特 性 研 究 の 一 例 と し て ， 第2報31に お い て プ ロ パ ン ガ ス を 燃 料 と す る 小 型 過 給 ボ イ ラ ー の 燃 焼 ・ 熱 伝 達 特 性 を 示 し た 。 こ の 報 告 で は ， 過 給 圧 ， 過 給 量 の 変 化 に 伴 う 壁 画 熱 負 荷 の 分 布 ， 燃 焼 効 率 の 変 化 な ど を 示 す と と も に ， 過 給 ボ イ ラ ー に 適 し た パ ー ナ の 改 良 例 を 示 し ， 過 給 ボ イ ラ ー の 熱 設 計 に 必 要 な い く つ か の 資 料 の 提 供 を 行 な っt:. o しか し ， 加 圧 雰 囲 気 下 で の 火 炎 の 形 状 や 輝 度 の 変 化 な ど 実 際 の 燃 焼 状 態 を 観 察 し ， ま た ， 燃 焼 特 性 に 及ぼす圧力の影響のみを整理しておくことも燃焼室の形状の設計や熱設計に必要なことである。したがって，本報でほriJ恨化が口
I
能な加圧燃焼器を作成し，プロパンガス 空 気 か ら な る 最 も 基本 的 な 燃 焼 形 態 の 一 つ で あ る 竺 気 旋 回 角 お よ び 噴 射 角 が 零 度 の パ ー ナ を 使 用 し た 同 軸 流 定 常 拡 散 107