| Summary: | 碩士 === 國立成功大學 === 航空太空工程學系 === 83 === The major subjective of this paper is to study of the effects
of jet flame lifting on the control of NOx emission. The NOx
emission from propane jet flame with different exit equivalence
ratio between 4 and 12 is compared. Three major NOx formation
zones in the flame were identified from experimental data of
flame temerature and NOx distributions,i.e.,(1)the flame base
region;(2)the potential core region;(3)the trailing flame. The
NOx formation rate depends on the formation machanism in each
region which depends strongly on the local temperature and
equivalence ratio. The lifted jet flame at the condition
Equivalence Ratio = 4 has the best control of NOx emission,
because the large scale vortices entrain large amount of air
resulting in lean premixing before the flame base which greatly
reduces the flame length , and the residence time of NOx
formation radicals. In addition, NOx formation in lean
combustion is dominated by the slower mechanisms of
superequilibrium NO and N2O intermediates in the flame base
region.
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