Experimental study of uniform droplets size and space
-
摘要: 液滴发生器产生液滴的尺寸和间距影响液滴层的辐射和蒸发特性,液滴尺寸及间距的可控性值得重点关注。根据Weber的射流不稳定修正方程,确定了均匀液滴流产生的无量纲波数及扰动频率范围,结合射流质量守恒,分析了均匀液滴流中液滴的尺寸和间距与无量纲波数的关系。在不同喷孔直径和射流压力下,对理论和实验结果进行了对比,验证了液滴尺寸和液滴间距的理论计算结果,为液滴层辐射蒸发特性的研究提供了依据。Abstract: The size and space of droplets produced by the droplet generator affect the radiation and evaporation characteristics of the droplet layer, and the controllability of the size and space of the droplets deserves special attention. According to Weber’s jet instability correction equation, the dimensionless wave number and disturbance frequency range of uniform droplet flow were determined. Combined with the mass conservation of jet, the relationship between the dimensionless wave number and the size and space of droplets in uniform droplet flow were analyzed. The theoretical and experimental results were compared under different nozzle diameters and jet pressures, which verified the theoretical calculation results of droplet size and spacing, and provided a basis for the study of droplet layer radiation evaporation characteristics.
-
Key words:
- uniform droplet /
- size /
- space /
- controllability /
- experimental study
-
表 1 工质参数
Table 1. Properties of working medium fluild
density/(kg·m−3) coefficient of viscosity/(Pa·s) surface tension/(N·m−1) 1070 0.04173 0.0373 表 2 不同频率下的均匀液滴生成结果
Table 2. Droplet formations under different frequencies
frequency/kHz droplet formations 2.0 2.2 2.4 2.6 2.8 3.0 3.2 -
[1] 苏著亭, 杨继才, 柯国土. 空间核动力[M]. 上海: 上海交通大学出版社, 2016.Su Zhuting, Yang Jicai, Ke Guotu. Space nuclear power. Shanghai: Shanghai Jiao Tong University Press, 2016 [2] Mattick A T, Hertzberg A. The liquid droplet radiator–An untralightweight heat rejection system for efficient energy conversion in space[J]. Acta Astronautica, 1982, 9(3): 165-172. doi: 10.1016/0094-5765(82)90084-4 [3] Brown R F, Kosson R. Liquid droplet radiator sheet design considerations[C]//Advanced Energy Systems—Their Role in Our Future, American Nuclear Society. 1984: 330-338. [4] White K A. Liquid droplet radiator development status[C]//22nd Thermophysics Conference. 1987. [5] Rayleigh J W S. On the instability of jets[J]. Proceedings of the Royal Society of London Mathematical society, 1878, 10: 4-12. [6] 王景龙, 陈文武, 马月仁, 等. 均匀液滴的形成机理及实验研究[J]. 强激光与粒子束, 2006, 18(5):709-712. (Wang Jinglong, Chen Wenwu, Ma Yueren, et al. Study of the uniform droplet stream[J]. High Power Laser and Particle Beams, 2006, 18(5): 709-712 [7] Crane L, Birch S, Mccormack P D. The effect of mechanical vibration on the breakup of a cylindrical water jet in air[J]. British Journal of Applied Physics, 1964, 15(6): 743-750. doi: 10.1088/0508-3443/15/6/319 [8] Cline H E, Anthony T R. The effect of harmonics on the capillary instability of liquid jets[J]. Journal of Applied Physics, 1978, 49(6): 3203-3208. doi: 10.1063/1.325267 [9] Totani T, Itami M, Nagata H, et al. Performance of droplet generator and droplet collector in liquid droplet radiator under microgravity[J]. Microgravity Science and Technology, 2002, 13(2): 42-45. doi: 10.1007/BF02872070 [10] 魏胜, 漆小波, 张占文, 等. 液滴发生器系统中流速及震荡频率的确定[J]. 强激光与粒子束, 2011, 23(7):1925-1928. (Wei Sheng, Qi Xiaobo, Zhang Zhanwen, et al. Determination of flow velocities and oscillation frequencies in liquid-droplet generator[J]. High Power Laser and Particle Beams, 2011, 23(7): 1925-1928 doi: 10.3788/HPLPB20112307.1925 -