加压条件下甲烷/空气预混火焰可燃极限的微重力实验研究  

EXPERIMENTAL STUDIES OF THE FLAMMABILITY LIMITS OF PREMIXED CH_4/AIR MIXTURES AT ELEVATED PRESSURES AT MICROGRAVITY

作　　者：张海[1] 樊融[1] 田雪沁[1] 许考[1] 汤根土[1] 王双峰[2] 万士昕[2] 

机构地区：[1]清华大学热能工程系热科学与动力工程教育部重点实验室,北京100084 [2]中国科学院力学研究所国家微重力实验室,北京100190

出　　处：《工程热物理学报》2010年第1期173-176,共4页Journal of Engineering Thermophysics

基　　金：国家自然基金项目资助(No.50576041)

摘　　要：本文成功搭建了适用于中国科学院力学研究所国家微重力实验室(NMLC)落塔的高压对冲火焰实验系统,并首次开展了微重力条件下加压对冲火焰实验,测定了一定张力条件下甲烷/空气层流预混火焰的熄灭极限。实验结果表明,随着压力的增高,甲烷/空气混合气体的可燃极限呈先增后降的非单调变化趋势,峰值发生在0.4 MPa左右。浮力对加压下微弱火焰熄灭极限的影响明显,在常重力条件下,相同张力下的熄灭极限较微重力条件下的偏大,峰值出现的压力略低。微重力条件下的实验结果与使用CHEMKIN的数值模拟的结果相当一致。An experimental system of counterflowing flames is built up,suitable for using the NMLC＇s 3.6 s drop tower.Experimental studies of the flammability limits of premixed CH_4/Air laminar flames at elevated pressures are conducted at microgravity.The extinction limits at fixed strain rates are successfully measured at pressure of 0.1～0.5 MPa.It is found that during the experimental pressure range,the extinction limits at a fixed strain rate increases and then decreases with pressure.The peak value is around 0.4 MPa at microgravity,and around 0.3 MPa at normal gravity.The buoyancy effect is noticeable to the extinction limits of the weakly burning flames,thereby the flammability limits. With its presence,the extinction limits at the same strain is larger while the pressure corresponding to the peak value is smaller.The experimental data obtained at microgravity agree well with simulated results and theoretical analyses.

关 键 词：加压 可燃极限 预混火焰 微重力 落塔 

分 类 号：TK124[动力工程及工程热物理—工程热物理]