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Effect of Turbulence on Radiation Intensity From Propane-Air Flames

1957; American Institute of Aeronautics and Astronautics; Volume: 27; Issue: 2 Linguagem: Inglês

10.2514/8.12613

1936-9980

Richard R. John, M. Summerfield,

Combustion and Detonation Processes

As a c o n t i n u a t i o n of a genera l inves t iga t ion of t h e cha rac t e r i s t i c s of h i g h speed t u r b u l e n t f lames, t h e effect of t u r b u l e n c e o n flame r a d i a t i o n i n t e n s i t y was m e a s u r e d i n o rde r t o d e t e r m i n e t h e e x t e n t of t h e possible i n t e r a c t i o n b e t w e e n t h e mix ing process a n d t h e c h e m i c a l r e ac t i on . I t was t h o u g h t t h a t s u c h i n t e r a c t i o n could reveal i tself by a n observable c h a n g e in t h e energy r a d i a t e d pe r u n i t m a s s of fuel. The energy m e a s u r e m e n t s were m a d e w i t h a s t a n d a r d i z e d p h o t o m u l t i p l i e r t h r o u g h t h r e e in te r fe rence filters cen t e red , respectively, a t 4500 A for CO b a c k g r o u n d r a d i a t i o n , 5150 A for C2, a n d 4300 A for CH. I n each case , t u r b u l e n c e r educed t h e specific i n t e n s i t y of t h e r a d i a t i o n . T h e r e d u c t i o n s were g rea te s t ( u p t o 35 pe r cen t ) for fuellean m i x t u r e s for t h e h i g h e s t i n t ens i t i e s of t u r b u l e n c e , a n d were s t ronge r for CO t h a n for e i t h e r CH or C2. T h e s e r e s u l t s i n d i c a t e t h a t t h e t u r b u l e n t mix ing does b reak u p w h a t would be a c o n t i n u o u s l a m i n a r flame shee t , a n d t h a t t h i s b r e a k u p modifies t h e chemica l r eac t ion a n d t r a n s p o r t processes in t h e flame zone . T h i s conc lus ion is in ag ree m e n t w i t h t h e hypo thes i s advanced in a previous pape r , t h a t t h e t u r b u l e n t flame is n o t mere ly a d i s to r t ed l a m i n a r flame b u t r a t h e r a deep zone of chemica l r e a c t i o n . I n t h i s pape r , t h e m a g n i t u d e of t h e i n t e n s i t y r e d u c t i o n is i n t e rp re t ed i n t e r m s of t h e r a t i o of t h e c h e m i c a l t i m e ' * t o t h e m i x i n g t i m e , a n d i t is conc luded t h a t flames of t h e t ype s t ud i ed he re a r e in t h e r a n g e of u n i t y for t h i s p a r a m e t e r .