排序方式: 共有6条查询结果,搜索用时 15 毫秒
1
1.
Ablation excited by current pulses is a very critical physical process in pulse plasma thrusters(PPT).Its effects on wall-plasma interaction directly determine the PPT performances.In order to reveal the process of the ablated wall interaction with the discharge plasma in PPT,ablation models formulated by three different boundary conditions at the wall-plasma interface are studied.These are the two widely used high-speed evaporation models(Model-L and Model-M),and the recently developed Keida-Zaghloul model(Model-K)of the Knudsen layer that takes into account the internal degrees of freedom on the energy flux conservation.First,fundamental mechanisms of the three ablation models are clarified by comparative analysis in order to gain a comprehensive understanding of the wall-plasma interaction.Then,the applicability of different ablation models with the numerical solutions of LES-6 PPT is investigated in detail using magnetohydrodynamic(MHD)modeling.Results show that Model-L and Model-M are actually special cases of Model-K when a simplified jump conditions limited by high velocity at the vapor/plasma interface is used;A ratio of ablation rate in Model-L to that in Model-M is about 0.8at the same wall surface temperature,while it rises to 1 at different surface temperature determined by Model-L and Model-M in PPT.Even though Model-K solution requires significant computational time,it shows more accurate ablation feature for the wall-plasma interaction and possesses better computing precision of impulse bit during post-pulse which is useful for future studies of the late time ablation. 相似文献
2.
3.
4.
基于水推进剂的脉冲等离子体推力器数值模拟 总被引:1,自引:0,他引:1
为揭示水推进脉冲等离子体推力器(WP-PPT)特有的烧蚀机理,解决WP-PPT工程化应用中所存在的关键问题,研究了WP-PPT的工作过程。建立了适用于WP-PPT的烧蚀模型,对WP-PPT的工作过程进行了仿真。将仿真结果与东京大学的实验结果进行比较。比较结果表明:由于部分推进剂气化或残留在通道内,仿真性能与实验结果不符;在样机的工作参数条件下,当参与放电的推进剂占总推进剂质量的20%时,仿真结果与实验结果较为相符;仿真结果中的元冲量、比冲以及能量转化效率分别为74μN.s、1 114s以及15.2%。分析实际实验过程,估算出约32%的推进剂参与放电,与仿真结果相近。研制快响应、高喷注均匀性的喷注器可提高WP-PPT性能。 相似文献
5.
6.
随着纳米技术和生物化学领域的发展, 对微观粒子的粒径和制造工艺提出更高的要求。气溶胶作为常见的工程纳米材料颗粒物, 在社会各行各业应用广泛。从气溶胶制备方法出发, 通过对大量相关文献的系统梳理, 综述气溶胶常用制备方法的研究进展, 对比分析不同气溶胶制备方法的适用场景, 明确不同气溶胶制备方法的使用要求, 归纳概述不同气溶胶制备方法的优缺点。在此基础上, 进一步综述不同时期国内外学者对各类方法的优化和完善, 深入剖析国内外学者的试验和研究成果, 对超临界流体技术在气溶胶制备中的应用进行分析与展望。 相似文献
1