当你在太空中点燃火焰会发生什么

Question

当你在太空中点燃火焰会发生什么

Answer 1

”比如生日蛋糕上的蜡烛火焰.因为重力的原因,这种火焰的形状呈气态的泪珠状——就是我们生活中经常见到的那种.热气升腾,牵动着新鲜的冷空气.在浮力的作用下,火焰喷射而出并且闪闪发光.
Sowe know all that.What we know less about,though,is the way fire behaves ...IN SPACE.In microgravity,according to the NASA video above,flames behavedifferently than they do here on Earth.Instead of the tear shape we're used tofrom our birthday cakes or Yankee Candle samples or what have you,thegravity-challeged flames form ...fire balls.Seriously.Unlike Earth-boundflames,"which expand greedily when they need more fuel," the videosays,"flame balls let the oxygen come to them." Oxygen and fuelcombine in a narrow zone at the surface of the sphere,rather than "hitherand yon throughout the flame."
这个我们都知道.而我们知之甚少的是：火焰在太空中的燃烧情况.根据美国航天航空局的这个视频：在微重力的作用下,太空中火焰的燃烧情况和在地球上的不一样.不同于于地球上的泪珠状火焰,太空中的火焰因挑战重力而形成一团团的火球.真的.该视频解说：“地球上的火焰需要更多的燃料时就会贪婪的扩张自己,而太空中的火球则是把氧气吸引过来.氧气和燃料在火球表面的一个有限区域内相互发生化学作用,而不是在火焰的整个范围内发生作用.”
Which isknowledge that might have practical applications here on Earth -- and,specifically,to Earth-bound automobiles and the combustion process they relyon for their energy.Williams and a colleague were conducting an ISS-basedexperiment called the Flame Extinguishment Experiment (yep:FLEX) when they madean accidental discovery:in space,droplets of fuel continued to burn.Evenafter their flames had extinguished.
了解了这一事实,可能有助于我们把它应用在地球上.比如汽车以及汽车燃料的燃烧过程.这名教授和一位同事是在进行工业标准规格的实验
——火焰熄灭实验——时得到这个意外发现的：在太空中,即便火焰已经熄灭,但是燃料依然在燃烧.
Yep:thefuel burned without flames.
是的,燃料在没有火焰的情况下也能够燃烧.
Or,moreaccurately,the fuel burned with flames that were so faint that they werealmost impossible to see.The FLEX experiment ended up testing the behavior of"cool flames"in space.The flame balls (fueled,in this case,by heptane) started outhot-burning.As they cooled,however,a different kind of burning seemed totake over.Cool flames burn at a relatively low-temperature 400 - 1,000 degreesFahrenheit,and their chemistry is completely different from that of a standardflame.While teardrop-shaped flames produce carbon dioxide,water,and soot,cool flames produce carbon monoxide and formaldehyde.And,importantly,whilecool flames on Earth extinguish immediately,the cool flames tested on thespace station burned for at least a minute.
或者,更准确的说法是：燃料在燃烧时的确有火焰存在,但是火焰真的太微弱了,以至于我们用肉眼无法看到.最终该实验演变成了在太空中测试“冷火焰”的燃烧情况.火球（该实验中,以康烷为燃料）开始剧烈燃烧.随着火势渐渐变小,另外一种燃烧形式似乎开始掌控全局.冷火焰在相对低的温度下燃烧——400-1000华摄氏度,而燃烧过程中的化学反应与地球的火焰完全不同.泪珠状的火焰产生的是二氧化碳,水和烟灰,而冷火焰产生的却是一氧化碳和甲醛.还有一点很重要的是,冷火焰在地球上会马上熄灭,而空间站中的冷火焰却至少可以再燃烧一分钟.视频中指出,这种现象对汽车以及其他靠燃烧驱动的交通工具来说具有巨大的应用意义.同时,我们还应该记住：如果你在太空中点燃一些生日蜡烛,你将会看到蜡烛的火焰呈球状,而不是泪珠状.