A Preliminary Design of a Magnesium Fueled Martian Ramjet Engine
A Preliminary Design of a Magnesium Fueled Martian Ramjet Engine
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DOI：
10.2514/6.2002-3788
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发表时间：
2002-07
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影响因子：
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通讯作者：
J. Linnell;T. Miller
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文献类型：
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作者：
J. Linnell;T. Miller
本文介绍了一种在火星大气中工作的含超化学计量比镁的固体燃料冲压发动机的初步设计研究。用于分析的方法和理论是从第一原理推导而来的。得到了一种可行的冲压发动机设计，其工作速度为4~5马赫，所需大气进气量是固体颗粒质量流量的9倍，燃烧室压力约为250kPa.对于100微米直径的镁颗粒，燃烧室的长度约为0.1米，对于500微米的颗粒，燃烧室的长度约为3至10米。药柱燃烧面积与喉部面积之比约为17。设计了9个8度斜道的进气道。入口高度和长度分别为0.35米和1.0米。选择了燃烧面积为0.45m的端燃药柱设计，当镁/硝酸钠混合物n=0.15，a=0.002125 m/S帕(其中回归速率为br=APCH)时，产生2900N的推力和400秒的比冲(经气体增强调整后)。通过改变弹道压力指数获得的推力预测表明，推力曲线低于阻力曲线的上限，操作是不可能的。
This paper presents a preliminary design study for a solid fuel ramjet containing a super-stoichiometric loading of magnesium for operation in the Martian atmosphere. The methods and theory used for analysis are derived from first principles. A feasible ramjet design was obtained which has an operational speed of Mach 4 to 5, requires nine times the mass intake of atmosphere relative to the mass flow rate of solid grain, and a chamber pressure of approximately 250 kPa. The length of the combustion chamber is approximately 0.1 meters for the case of 100-micron diameter magnesium particles, and 3 to 10 meters for the case of 500-micron particles. The ratio of grain burn area to throat area is approximately 17. A suitable inlet design was made which would have nine 8-degree ramps. The inlet height and length would be 0.35 and 1.0 meter, respectively. An end-burning grain design was selected with a burn area of 0.45 m. Hypothetical ballistic values of the magnesium/ sodium nitrate mixture of n=0.15 and a=0.002125 m/s Pa (where the regression rate is br=aPch), produce a thrust of 2900 N and a specific impulse (adjusted for gas augmentation) of 400 seconds. Thrust predictions obtained by varying the ballistic pressure exponent indicate an upper limit above which the thrust curve falls below the drag curve and operation is not possible.