空间科学学报2018，Vol.38Issue(2)：227-233,7.DOI:10.11728/cjss2018.02.227
浮力效应对射流扩散火焰转捩特性影响的实验研究
Experimental Study of Buoyancy Effect on Transitional Jet Diffusion Flames
摘要
Abstract
The transition to turbulence of coflow propane-fueled jet diffusion flames was investigated experimentally with varying air coflow velocities,and the buoyancy-suppressing effect of coflow was analyzed to reveal the buoyancy effect on the transition and stability of diffusion flames.Compared to jet flames in quiescent air,a coflow with relatively high velocity can suppress the influence of buoyancy on transitional flames,and make the critical nozzle Reynolds number of transition to turbulent flame increasing,i.e.,the transition process is delayed by coflow.When the coflow velocity is small,however,the critical Reynolds number stays almost the same.In the transitional regime,diffusion flames are characterized by periodic oscillation,and the oscillation amplitude decreases with increasing coflow velocity.As coflow velocity increases further,the periodicity of flame oscillation disappears eventually,and presents a randomness.Additionally,the experiments show that a larger jet nozzle results in a greater critical Reynolds number of flame transition.Such an observation is explained in terms of the local fuel jet properties taking into account of the influence of diffusion flame.关键词
扩散火焰/湍流转捩/火焰稳定性/同轴伴流/浮力效应Key words
Diffusion flame/Transition to turbulence/Flame stability/Coflow/Buoyancy effect分类
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李丹,王双峰..浮力效应对射流扩散火焰转捩特性影响的实验研究[J].空间科学学报,2018,38(2):227-233,7.基金项目
中国科学院国家空间科学中心空间科学任务概念课题资助(XDA15007602) （XDA15007602）
