过冷大水滴（SLD）结冰过程中，影响水滴变形与破碎及其导致的效应的因素众多，多种影响因素耦合作用于水滴变形与破碎的规律还未得到清晰认识。采用数值计算的手段，模拟了SLD运动过程中的变形与破碎现象，分别研究了水滴直径、流场速度及绕流物体尺寸变化对水滴破碎与变形及其效应的影响。通过研究，提出了包含SLD的典型流场区域划分方法，得到了不同因素对水滴破碎区域面积、物面的水滴收集特性、破碎子水滴分布特性的影响规律，发现水滴直径、流场速度、翼型前缘半径与变形和破碎影响撞击特性的程度呈正相关关系。在此基础上，提出了一个综合影响参数X，线性回归分析的结果初步说明，X是表征水滴变形与破碎及其效应的合适参数。相关工作可以为SLD结冰的计算、试验以及防/除冰设计提供参考。
In the icing of Supercooled Large Droplet (SLD), many factors affect droplets deformation and breakup. The laws of multiple factors influencing on the deformation and breakup of droplets have not been understood clearly. Adopting numerical calculation, the effects of droplets diameter, flow field velocity and the variation of object size on SLD deformation and breakup are studied. Then a method of dividing typical flow fields region including SLD is proposed. The influence laws of different factors on the area of droplets breakup region, the efficiency of droplets collection and the distribution of sub-droplets are obtained. It's found that the SLD diameter, air velocity and leading edge radius of airfoil are positively associated with the effect of deformation and breakup to droplets impingement and collection coefficient. On this basis, a comprehensive influence parameter, X, is proposed. The results of the linear regression analysis show that X is an appropriate parameter to characterize the effects of deformation and breakup. The above work can provide reference to the calculation and test of SLD icing and the anti/de-icing design.
[1] CEBECI T, KAFYEKE F. Aircraft icing[J]. Annual Review of Fluid Mechanics, 2003, 35:11-21.
[2] BRAGG M B, BROEREN A P, BLUMENTHAL L A. Iced-aircraft aerodynamics[J]. Progress in Aerospace Sciences, 2005, 41:323-362.
[3] 杜雁霞,李明,桂业伟,等.飞机结冰热力学行为研究综述[J]. 航空学报, 2017, 38(2):520706. DU Y X, LI M, GUI Y W, et al. Review of thermodynamic behaviours in aircraft icing process[J]. Acta Aeronautica et Astronautica Sinica, 2017, 38(2):520706(in Chinese).
[4] Aircraft Accident Report. In-flight icing encounter and loss of control:NTSB/AAR-96/01[R]. Washington D.C.:National Transportation Safety Board, 1994.
[5] TSAO J. Additional results of glaze icing scaling in SLD conditions[C]//The 8th AIAA Atmospheric and Space Environments Conference. Reston, VA:AIAA, 2016.
[6] WIERZBA A. Deformation and breakup of liquid drops in a gas stream at nearly critical Weber numbers[J]. Experiments in Fluids, 1990, 9(1):59-64.
[7] STONE H A. Dynamics of drop deformation and breakup in viscous fluids[J]. Annual Reviews of Fluid Mechanics, 1994, 26:65-102.
[8] KENNEDY J, ROBERTS J. Rain ingestion in a gas turbine engine[C]//The 4th Institute for Liquid Atomization and Spray Systems (ILASS) Meeting, 1990.
[9] ZHANG C, LIU H. Effect of drop size on the impact thermodynamics for supercooled large droplet in aircraft icing[J]. Physics of Fluids, 2016, 28:062107.
[10] TAN C, PAPADAKIS M. Droplet breakup, splashing and re-impingement on an iced airfoil[C]//The 4th AIAA Theoretical Fluid Mechanics Meeting. Reston, VA:AIAA, 2005.
[11] O'ROURKE P J, AMSDEN A. The TAB method for numerical calculation of spray droplet breakup[C]//The International Fuels and Lubricants Meeting and Exposition, 1987.
[12] 张辰, 孔维梁, 刘洪.大粒径过冷水滴结冰模拟破碎模型研究[J]. 空气动力学学报, 2013, 31(2):144-150. ZHANG C, KONG W L, LIU H. An investigation on the breakup model for icing simulation of supercooled large droplets[J]. Acta Aerodynamica Sinica, 2013, 31(2):144-150(in Chinese).
[13] ANTTHO A, MOHIUDEEN A, KARA K. Determination of water droplet collection efficiency:An empirical model[C]//AIAA Atmospheric Flight Mechanics Conference. Reston, VA:AIAA, 2017.
[14] 杜晨慧, 郁嘉, 林贵平, 等. 二维翼型大尺寸过冷水滴撞击特性及冰形分析[J]. 航空动力学报, 2014, 29(4):783-791. DU C H, YU J, LIN G P, et al. Analysis on supercooled large droplet impingement characteristics and shape of two-dimensional airfoils[J]. Journal of Aerospace Power, 2014, 29(4):783-791(in Chinese).
[15] 桑为民,蔡旸,鲁天. 变形与破碎特性对SLD结冰过程影响[J].航空动力学报, 2017, 32(7):1537-1544. SANG W M, CAI Y, LU T. Effect of deformation and breakup characteristic on supercooled large droplet icing process[J]. Journal of Aerospace Power, 2017, 32(7):1537-1544(in Chinese).
[16] 易贤. 飞机积冰的数值计算与积冰试验相似准则研究[D]. 绵阳:中国空气动力研究与发展中心, 2007:20-27. YI X. Numerical computation of aircraft icing and study on icing test scaling law[D]. Mianyang:China Aerodynamics Research and Development Center, 2007:20-27(in Chinese).
[17] VILLEDIEU P, TRONTIN P, GUFFOND D, et al. SLD Lagrangian modelling and capability assessment in the frame of ONERA 3D icing suite[C]//The 4th AIAA Atmospheric and Space Environments Conference. Reston, VA:AIAA, 2012.
[18] 易贤,朱国林,王开春,等. 翼型积冰的数值模拟[J].空气动力学学报, 2002, 20(4):428-433. YI X, ZHU G L, WANG K C, et al. Numerically simulating of ice accretion on airfoil[J]. Acta Aerodynamica Sinica, 2002, 20(4):428-433(in Chinese).
[19] American Society of Testing Materials. Standard terminology relating to liquid particle statistics:E1620-97[S]. Washington, D.C.:American Society for Testing Material, 1996:1-3.
[20] LIU B, MATHER D, REITZ D. Modeling the effects of drop drag and breakup on fuel sprays:SAE paper 930072[R]. Detroit, Michigan:Society of Automotive Engineers, 1993.
CJA