一氧化二氮催化分解的研究与应用

为了建立小卫星新型多模式推进系统，英国Surrey公司从1990年开始研究一氧化二氮催化分解。研究重点是可多次肩动的一氧化二氮单元推进剂推力室，适用于小卫星的位置保持和相位保持。推力室催化剂床的尺寸取决于催化剂床装填系数和轴向温度分布。建议采用Ergun公式估算通过催化剂床的压力降。推进剂最大流量依赖于一氧化二氮供应系统自身增压能力。     

Combustion characteristics of a hydroxylammonium nitrate based liquid propellant. Combustion mechanism and application to thrusters

A new composition of hydroxylammonium nitrate based solution containing ammonium nitrate, methanol, and water was developed for monopropellant in a reaction control system (RCS) as an alternative to conventional hydrazine. In comparison with hydrazine, this solution has a 20% higher specific impulse, 1.4 times higher density, and lower freezing point and toxicity. The linear burning rate of the solution is moderate at the operating pressures of RCS thrusters. It was found that the linear burning rate had some characteristics whose mechanisms had not been understood. The combustion mechanism of this solution was investigated. The burning behavior was observed using a medium speed camera, and a temperature profile for the combustion wave was measured with a 2.5 μm diameter thermocouple. From these results, the instability of the liquid-gas interface may trigger a sudden increase in the burning rate, and methanol was found to be effective in reducing the bubble growth rate in the solution. The reactivity of several catalysts was evaluated in an open-cup test, and the S405 catalyst for hydrazine showed the best performance among them. Thruster tests were conducted using the S405 catalyst with variation in the propellant mass flow rate, catalyst bed configuration, and length-to-diameter ratio of the combustor. As a result, parameters were determined that ensured long operating time. The model thruster operated stably for up to 100 sec with a specific impulse I _sp = 240 sec, which corresponds to a 90% efficiency. __________ Translated from Fizika Goreniya i Vzryva, Vol. 45, No. 4, pp. 109–120, July–August, 2009. An erratum to this article can be found at     

高能单元推进剂化学结构和热分解特征与燃速的相关性

利用以准一维气相反应流为基础的固体推进剂稳态燃烧模型,研究了高能单元推进剂AP、HM X、RDX、CL-20和NQ的化学结构、热分解特征与燃烧性能的相关性。改进了高能单元推进剂燃速预估模型,使其可由高能单元推进剂的化学结构和基本热分解特性出发,预估单元推进剂的燃烧性能。通过与实测燃速的比较,验证了模型假设的合理性。     

Catalytic Decomposition of Hydrazine over Supported Molybdenum Nitride Catalysts in a Monopropellant Thruster

The catalytic decomposition of hydrazine over a series of MoN_x/-Al₂O₃ catalysts with different Mo loadings was investigated in a monopropellant thruster (10 N). When the Mo loading is equal to or higher than the monolayer coverage of MoO₃ on -Al₂O₃, the catalytic performance of the supported molybdenum nitride catalyst is close to that of the conventionally used Ir/-Al₂O₃ catalyst. The MoN_x/-Al₂O₃ catalyst with a loading of about 23 wt% Mo (1.5 monolayers) shows the highest activity for hydrazine decomposition. There is an activation process for the MoN_x/-Al₂O₃ catalysts at the early stage of hydrazine decomposition, which is probably due to the reduction of the oxide layer formed in the passivation procedure.     

N2O单组元微型推进器内参数敏感性的研究

对一种新型的推进剂N2O在催化剂床中的流动和传热传质进行了数值模拟研究。分析和研究了催化剂的孔隙率、长度、比表面积、传质Sh对推进系统的瞬态及稳态性能的影响。结果表明：推进系统的瞬态性能与催化剂的孔隙率和长度有关．稳态性能与催化剂的比表面积及推进剂在催化剂床内的传质Sh有关。研究结果为进一步改善微型化学火箭内部结构、提高其推进性能提供了理论依据。     

LP1846液滴在酒精火焰中的燃烧研究

该文研究了初始直径为1.8～2.4mm的LP1846单滴,在950C的酒精火焰中汽化、分解、燃烧的特性,给出了液滴从进入火焰到燃尽全过程的时间序列照片.定量测试了液滴的着火延迟期、生存期以及液滴直径随时间的变化关系,并计算了液滴表面积平均减小速率.     

无毒单元发动机催化燃烧过程可视化试验研究

无毒单元推进系统具有性能高,操作简单、爆炸风险低等特点,未来将全面替代肼类推进系统。深入研究无毒发动机催化燃烧过程,采用透明燃烧室对无毒单元发动机进行可视化研究,并与金属燃烧室试验结果进行比对,试验结果表明:在室压快速上升阶段,推进剂快速反应处于前床,发动机效率很低;在室压平稳上升阶段,发动机的催化燃烧部位逐渐从前床向后床扩展,推进剂催化燃烧主要在催化床核心部位进行;随着发动机连续工作时间增加,发动机燃烧强度增加和燃烧效率提高。     

Ignition and Extinction of Monopropellant Droplet with Lewis Number Different from Unity

ＩｇｎｉｔｉｏｎａｎｄＥｘｔｉｎｃｔｉｏｎｏｆＭｏｎｏｐｒｏｐｅｌｌａｎｔＤｒｏｐｌｅｔｗｉｔｈＬｅｗｉｓＮｕｍｂｅｒＤｉｆｆｅｒｅｎｔｆｒｏｍＵｎｉｔｙ￥ＦｅｒｎａｎｄｏＦ．Ｆａｃｈｉｎｉ（ＩｎｓｔｉｔｕｔｏＮａｃｉｏｎａｌｄｅＰｅｓｑｕｉｓａｓＥ...     

单组元粉末发动机内流场数值模拟研究

为了研究粉末发动机的工作特性,建立了以火药颗粒为燃料的单组元粉末发动机理论模型,采用CE/SE方法对粉末发动机内流场进行数值模拟。分析了初始颗粒粒径、初始固相体积分数以及堵盖对粉末发动机燃烧过程的影响。计算结果表明:颗粒初始粒径的减小和固相初始体积分数的提高均能提高发动机燃烧室内的压力; 固相体积分数对发动机内温度峰值影响不大; 在点传火阶段,堵盖能提高点火压强,堵盖打开压力越大,增压越明显。     

旋转燃烧室中燃烧性能研究

针对燃烧室本身旋转及使用单组元液体推进剂的特点，对此两相湍流反应流，在质量，动量和能量传输基础上，建立了在旋转燃烧室中单 液体推进剂雾化燃烧过程计算的模型和边界条件。