火箭推进

虽然阵列式结构的离子电喷雾推力器具有小体积、高比冲、高推力分辨率等优点,但是其发展受到了缺乏理论研究的限制。针对该问题,基于多点发射现象发展了描述推力器束电流的数学模型,并通过智能优化算法对模型中的经验系数进行了辨识,研究了高、低电压下束电流及发射行为存在的不同特征。基于Sobol方法进行了全局敏感性分析,研究了发射体结构的几何参数对束电流的影响程度。模型计算结果与试验结果基本一致,当电压大于1.5 kV时,发射点基底半径与多孔储层孔隙半径相当,外加电场主要影响束电流的非线性增加; 电压小于1.5 kV时,发射点数量较少,基底半径是多孔储层孔隙半径的1.5倍,发射点数量是影响束电流大小的关键因素。敏感性分析结果表明,发射体尖端与提取极之间的距离对束电流的影响程度最大,其1阶敏感性指数为0.841,在加工制造中须严格控制其公差大小。

Although the ion electrospray thruster with an array emitter has advantages such as small volume, high specific impulse, and high thrust resolution, its development has been limited by the lack of theoretical researches. To address this issue, a mathematical model describing the beam current of the thruster based on the multi-site emission phenomenon was developed, and the empirical coefficients in the model were identified using intelligent optimization algorithms. The different characteristics of the beam current and emission behavior under high and low voltages were studied. Global sensitivity analysis based on the Sobol method was conducted to investigate the impact of geometric parameters of the emitter structure on the beam current. The model calculation results are basically consistent with the experimental data. When the voltage is greater than 1.5 kV, the base radius of the emission site is equivalent to the pore radius of the porous reservoir, and the external electric field mainly affects the nonlinear increase of the beam current. When the voltage is less than 1.5 kV, the number of emission sites is small, the base radius is 1.5 times the pore radius of the porous reservoir, and the number of emission sites is a key factor affecting the size of the beam current. The sensitivity analysis results show that the distance between the tip of the emitter and the extractor has the greatest impact on the beam current, with a first order sensitivity index of 0.841, and its tolerance must be strictly controlled in manufacturing processes.

引言
1 模型与方法
2 结果与讨论
3 结论

图1 锥形多孔发射体和几何参数示意图<br/>Fig.1 Schematic of a conical porous emitter with key dimensions

图1 锥形多孔发射体和几何参数示意图
Fig.1 Schematic of a conical porous emitter with key dimensions

图2 多点发射示意图<br/>Fig.2 Schematic of multi-site emission

图2 多点发射示意图
Fig.2 Schematic of multi-site emission

表1 DA算法的搜索域和超参数设置<br/>Tab.1 Search domain and super parameters setting of Dual Annealing algorithm

表1 DA算法的搜索域和超参数设置
Tab.1 Search domain and super parameters setting of Dual Annealing algorithm

表2 几何参数变化范围<br/>Tab.2 Variation range of parameters

表2 几何参数变化范围
Tab.2 Variation range of parameters

图3 AFET-2推力器示意图<br/>Fig.3 Schematic of an AFET-2 thruster

图3 AFET-2推力器示意图
Fig.3 Schematic of an AFET-2 thruster

图4 模型计算结果与Busek试验结果对比<br/>Fig.4 Model prediction results compared with experimental data in positive mode of Busek

图4 模型计算结果与Busek试验结果对比
Fig.4 Model prediction results compared with experimental data in positive mode of Busek

图5 发射点数量的预测结果<br/>Fig.5 Prediction results fornumber of active emission sites

图5 发射点数量的预测结果
Fig.5 Prediction results fornumber of active emission sites

图6 模型计算结果与AFET-2试验结果对比<br/>Fig.6 Model prediction results compared with experimental data in positive mode of AFET-2 thruster

图6 模型计算结果与AFET-2试验结果对比
Fig.6 Model prediction results compared with experimental data in positive mode of AFET-2 thruster

图7 整体预测与分段预测的发射点数量<br/>Fig.7 The number of emission sites at overall and piecewise prediction

图7 整体预测与分段预测的发射点数量
Fig.7 The number of emission sites at overall and piecewise prediction

图8 整体预测与分段预测的残差比较<br/>Fig.8 Schematic of residual under overall prediction and piecewise prediction

图8 整体预测与分段预测的残差比较
Fig.8 Schematic of residual under overall prediction and piecewise prediction

图9 分段预测结果与AFET-2试验结果对比<br/>Fig.9 Piecewise prediction compared to experimental data in positive mode of AFET-2 thruster

图9 分段预测结果与AFET-2试验结果对比
Fig.9 Piecewise prediction compared to experimental data in positive mode of AFET-2 thruster

图10 基于Sobol方法的全局敏感性分析结果<br/>Fig.10 Results of Sobol sensitivity analysis

图10 基于Sobol方法的全局敏感性分析结果
Fig.10 Results of Sobol sensitivity analysis

图11 忽略尖端“帽形”部分的锥形发射体平面示意图<br/>Fig.11 Planar schematic of conical emitter without the cap part of the tip

图11 忽略尖端“帽形”部分的锥形发射体平面示意图
Fig.11 Planar schematic of conical emitter without the cap part of the tip

[1] 郭登帅, 康小明, 刘欣宇, 等. 场发射电推力器的研究现状及其关键技术[J]. 火箭推进, 2018, 44(4): 1-9.
[2]于达仁, 牛翔, 王泰卜, 等. 面向空间引力波探测任务的微推进技术研究进展[J]. 中山大学学报(自然科学版), 2021, 60(1): 194-212.
[3]GONG Y G, LUO J, WANG B. Concepts and status of Chinese space gravitational wave detection projects[J]. Nature Astronomy, 2021, 5: 881-889.
[4]陈茂林, 刘旭辉, 周浩浩, 等. 适用于微纳卫星的微型电推进技术研究进展[J]. 固体火箭技术, 2021, 44(2): 188-206.
[5]于达仁, 乔磊, 蒋文嘉, 等. 中国电推进技术发展及展望[J]. 推进技术, 2020, 41(1): 1-11.
[6]LEGGE R S, LOZANO P, MARTINEZ-SANCHEZ M. Fabrication and characterization of porous metal emitters for electrospray thrusters[C]//30th International Electric Propulsion Conference. Florence, Italy: IEPC, 2007.
[7]CHEN C, CHEN M L, ZHOU H H. Characterization of an ionic liquid electrospray thruster with a porous ceramic emitter[J]. Plasma Science and Technology, 2020, 22(9): 094009.
[8]LIU X Y, KANG X M, DENG H W, et al. Energy properties and spatial plume profile of ionic liquid ion sources based on an array of porous metal strips[J]. Plasma Science and Technology, 2021, 23(12): 125502.
[9]张天平, 张雪儿, 李璇. 离子与霍尔电推进性能和质量的工程数据模型[J]. 火箭推进, 2022, 48(1): 1-13.
[10]ZIEMER J, MARRESE-READING C, CUTLER C, et al. In-flight verification and validation of colloid micro-thruster performance[C]//2018 Joint Propulsion Conference. Reston, Virginia: AIAA, 2018.
[11]KREJCI D, MIER-HICKS F, FUCETOLA C P, et al. Design and characterization of a scalable ion electrospray propulsion system[C]//30th International Symposium on Space Technology and Science. Hyogo, Japan: ISTS, 2015.
[12]JORNS B A, GORODETSKY A A, LASKY I M, et al. Uncertainty quantification of electrospray thruster array lifetime[C]//36th International Electric Propulsion Conference. [S.l.]: IEPC, 2019.
[13]ST PETER B, DRESSLER R A, CHIU Y H, et al. Electrospray propulsion engineering toolkit(ESPET)[J]. Aerospace, 2020, 7(7): 91.
[14]雪佳强, 郭宁, 孟伟, 等. 多孔阵列式电喷雾推力器纯离子电流的物理模型[J]. 推进技术, 2023, 44(6): 171-182.
[15]DRESSLER R A, PETER B S, CHIU Y H, et al. Multiple emission sites on porous glass electrospray propulsion emitters using dielectric propellants [J]. Journal of Propulsion and Power, 2022, 38(5): 809-821.
[16]NATISIN M R, ZAMORA H L. Performance of a fully conventionally machined liquid-ion electrospray thruster operated in PIR[C]//36th International Electric Propulsion Conference. [S.l]: IEPC, 2019.
[17]WHITTAKER C B, GORODETSKY A, JORNS B. Quantifying uncertainty in the scaling laws of porous electrospray emitters[C]//AIAA Propulsion and Energy 2020 Forum. Reston, Virginia: AIAA, 2020.
[18]WRIGHT P, WIRZ R E. Transient flow in porous electrospray emitters[C]//AIAA Propulsion and Energy 2021 Forum. Reston, Virginia: AIAA, 2021.
[19]程世豪. 离子液体微型电推进器三维仿真与性能分析[D]. 南京: 南京航空航天大学, 2017.
[20]COFFMAN C, ANCHEZ M, HIGUERA F J, et al. Structure of the menisci of leaky dielectric liquids during electrically-assisted evaporation of ions[J]. Applied Physics Letters, 2016, 109(23): 231602.
[21]VIRTANEN P, GOMMERS R, OLIPHANT T E, et al. SciPy 1.0: fundamental algorithms for scientific computing in Python[J]. Nature Methods, 2020, 17(3): 261-272.
[22]SOBOL I M. Global sensitivity indices for nonlinear mathematical models and their Monte Carlo estimates[J]. Mathematics and Computers in Simulation, 2001, 55(1/2/3): 271-280.
[23]SALTELLI A, ANNONI P, AZZINI I, et al. Variance based sensitivity analysis of model output. Design and estimator for the total sensitivity index[J]. Computer Physics Communications, 2010, 181(2): 259-270.
[24]HERMAN J, USHER W. SALib: an open-source Python library for sensitivity analysis[J]. The Journal of Open Source Software, 2017, 2(9): 97.
[25]YANG Y T, GUO D W, LI X K, et al. Development and characterization of a novel porous-media borosilicate glass ion sources for electrospray thruster[J]. Aerospace, 2021, 8(10): 297.
[26]NATISIN M R, ZAMORA H L, HOLLEY Z A, et al. Efficiency mechanisms in porous-media electrospray thrusters[J]. Journal of Propulsion and Power, 2021, 37(5): 650-659.
[27]NATISIN M R, ZAMORA H L, MCGEHEE W A, et al. Fabrication and characterization of a fully conventionally machined, high-performance porous-media electrospray thruster[J]. Journal of Micromechanics and Microengineering, 2020, 30(11): 115021.

备注

引言

1 模型与方法

2 结果与讨论

3 结论

期刊信息