Sampling and Analysis of Combustion Gases

Rap id cooling of c o m b u s t i o n gas samples in order to f r e e z e t h e h i g h t e m p e r a t u r e compos i t ion is d iscussed. S m a l l d i a m e t e r s a m p l i n g probes have used expans ion , d i l u t i o n by i n e r t gas , a n d cooling f rom t h e t u b e wall, a n d have accompl i shed signif icant cool ing i n a few m i c r o seconds . Based o n s o m e expe r imen ta l t e s t s , t h i s cooling t i m e is j u d g e d to be sat isfactor i ly s h o r t . Analy t ica l m e t h o d s for c o m b u s t i o n gases a re discussed w i t h e m p h a s i s o n those newer m e t h o d s of s ignif icant p romi se , m a s s spectroscopy, inf rared a n d u l t rav io le t abso rp t ion spec t ros copy. T h e l a t t e r a re especially n o t e d , s ince t hey are appl icable whi le t h e gases reside in t h e r eac t i on c h a m b e r . Mass spectroscopy a n d Orsa t ana lys is have yielded s imi la r r e su l t s o n given s a m p l e s .