本帖最后由 猎鹰 于 2013-10-7 23:55 编辑
据说乙醇/甲醇比冲低于煤油就是因为里面具有羟基~~~~~~剩下就不需要我解释了。
貌似就是这一篇https://www.kechuang.org/t/60309
据说乙醇/甲醇比冲低于煤油就是因为里面具有羟基~~~~~~剩下就不需要我解释了。
貌似就是这一篇https://www.kechuang.org/t/60309
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讨论/结晶水的加入是否会提高比冲
水的单位质量产气量无疑是巨大的,如果用结晶水合物代替无水化合物，是否可以增加燃料的比冲呢
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c7h5n2o4 发表于 2013-10-10 21:19
这篇好像没讲
就在开头的一段啊~~~~~~~
During and immediately after World War II, alcohols (primarily ethyl alcohol, occasionally methyl alcohol) were the single most common fuel for large liquid-fueled rockets. Its high heat of vaporization kept regeneratively-cooled engines from melting, especially considering that alcohols would typically contain several percent water.
由于内部含水
However, it was recognized that hydrocarbon fuels would increase engine efficiency, due to a slightly higher density, the lack of an oxygen atom in the fuel molecule, and negligible water content. Whatever hydrocarbon was chosen, though, would have to replicate alcohol's coolant ability.
碳氢燃料缺乏氧原子（乙醇中的氧来源于羟基）
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燃料的比冲主要由温度和气体相对分子量决定（还有燃烧室压强）。你说的产气量也就是气体相对分子量。气体相对分子量小比冲大，从这点上讲，结晶水有利于提高比冲。但加入结晶水会使燃气温度降低（同样质量的燃料产生的能量少了，而气体多了，所有更少的能量要分给更多的气体），从这点讲比冲降低了。综合起来怎么变化就要看哪个占主导了。从实际情况来看是加入结晶水比冲降低了。
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