Numerical study on the aerodynamics of a rocket fairing half in the continuum regime of the reentry process
FENG Rui1,2, LIU Yu1,2, ZHANG Zhang1,2, HE Qingsong1,2, WU Zhuo1,2, TENG Haishan1,2, JIA He1,2
1. Beijing Institute of Space Mechanics & Electricity, Beijing 100094, China; 2. Laboratory of Aerospace Entry, Descent and Landing Technology, China Aerospace Science and Technology Corporation, Beijing 100094, China
Abstract：[Objective] Recently, a trend has been developed toward the high-density launches of launch rockets, and unprecedented attention has been paid to the impact zone safety of rocket's separated fairings. Great pressure on controlling the environmental safety of the rocket's fairing half results from the low accuracy and large uncertainty in reentry trajectory calculation using the traditional mass point ballistic model. The main reason for the difficulty in reliably calculating the reentry ballistics of the fairing half is the lack of comprehensive studies on the half fairing's aerodynamic characteristics under various reentry flight conditions. This study aims to deal with the problem of reliable prediction of the reentry impact point of fairing half after separation from the launch vehicle. By using the computational fluid dynamics (CFD) approach, a comprehensive study is conducted here on the aerodynamics of the fairing half of a common rocket in the continuum regime of its reentry process. The incoming flow parameters for multiple computational conditions are extracted from the measured ballistic data of a certain flight mission. The calculation of various conditions is set and controlled by a parametric automated script. To obtain the relevant aerodynamic coefficients, the steady-state numerical solution for three-dimensional Reynolds-averaged Navier-Stokes (RANS) equations is obtained using the finite volume method. The Roe scheme and the implicite lower-upper symmetric Gauss-Seidel (LU-SGS) solution algorithms are used to obtain the discretization solution of the flow control equations. A numerical model uses an unstructured mesh structure, with a total mesh number approximating 15 million, and generates enough prismatic layers on the surface. The turbulence model is a two-equation realizable k-ε model. Aerodynamic coefficients of the fairing half were obtained under various flight conditions, where the Mach number varied from 0.20 to 5.95, while the angle of attack (AOA) varied from 0° to 360°. Numerical results indicated that:1) Two trim angles of attack existed in the supersonic and hypersonic regions, with the first trim AOA ranging from 85° to 97° and the second trim AOA ranging from 256° to 254°. 2) Similarly, two trim angles of attack existed in the transonic and subsonic regions, with the first trim AOA ranging from 85° to 88° and the second trim AOA ranging from 259° to 252°. 3) Whether in the supersonic or transonic region, the fairing half behaved statically stabled at its first trim AOA in axial roll direction at 0° roll angle but non-statically stabled at the second trim AOA. 4) Adjusting the position of the center of mass of the fairing half along its axial direction could effectively change its trim AOA, which led to a significant change in the lift-to-drag ratio in turn. However, adjusting the position of the center of mass along its radial direction had little effect on the trim AOA and the lift and drag characteristics. By utilizing the obtained database of aerodynamic coefficients, the 6-degrees-of-freedom reentry model for the fairing half can be achieved, helping improve the prediction accuracy of the impact area significantly. In the hypersonic region, the difference in the aerodynamic coefficients under the same AOA condition is below 15%, indicating that in the continuum region, when the Mach number is greater than 5.95, the required aerodynamic coefficients for the ballistic reentry analysis are similar to those of Mach number is 5.95. Due to the obvious differences in the aerodynamic coefficients in the transonic or subsonic region, the required aerodynamic coefficients for the ballistic reentry analysis can be interpolated from the obtained database. The trim AOA and the corresponding lift-to-drag ratio can be effectively changed by adjusting the position of the center of mass of the fairing half along its axial direction, thus adjusting or controlling the impact point within a certain range.
冯瑞, 刘宇, 张章, 何青松, 吴卓, 滕海山, 贾贺. 火箭整流罩半罩再入过程连续流区气动特性数值研究[J]. 清华大学学报（自然科学版）, 2023, 63(3): 414-422.
FENG Rui, LIU Yu, ZHANG Zhang, HE Qingsong, WU Zhuo, TENG Haishan, JIA He. Numerical study on the aerodynamics of a rocket fairing half in the continuum regime of the reentry process. Journal of Tsinghua University(Science and Technology), 2023, 63(3): 414-422.
[1] 张涛, 徐倩, 李聃, 等. 基于大型翼伞可控回收的箭体结构与分离方案设计[J]. 导弹与航天运载技术, 2020, 6(2):11-15. ZHANG T, XU Q, LI D, et al. Launch vehicle structure design and separation technology based on controllable recovery using large-scale parachute system[J]. Missiles and Space Vehicles, 2020, 6(2):11-15. (in Chinese) [2] 滕海山. 运载火箭分离体可控翼伞精确回收系统技术研究[D]. 长沙:国防科学技术大学, 2017. TENG H S. Research on the techniques of precise recovery system for the controllable parafoil of launch vehicle separate bodies[D]. Changsha:National University of Defense Technology, 2017. (in Chinese) [3] 闫指江, 吴彦森, 宫宇昆, 等. 整流罩头部钝度比对运载火箭气动性能影响研究[J]. 导弹与航天运载技术, 2020, 6(4):35-38, 44. YAN Z J, WU Y S, GONG Y K, et al. Study on the influence of blunt ratio of fairing head on aerodynamic performance of launch vehicle[J]. Missiles and Space Vehicles, 2020, 6(4):35-38, 44. (in Chinese) [4] 杨希祥, 周张, 彭科. 基于Kriging方法的整流罩气动外形设计优化[J]. 固体火箭技术, 2014, 37(2):167-171, 177. YANG X X, ZHOU Z, PENG K. Aerodynamic shape design optimization of fairing based on Kriging method[J]. Journal of Solid Rocket Technology, 2014, 37(2):167-171, 177. (in Chinese) [5] MURMAN S M, DIOSADY L. Simulation of a hammerhead payload fairing in the transonic regime[C]//Proceedings of the 54th AIAA Aerospace Sciences Meeting. San Diego, USA:AIAA, 2016. [6] MAHAMUNI P, BHANSALI P, KULKARNI A, et al. Aerodynamic study of payload fairing[J]. International Journal of Innovative Research in Science, Engineering and Technology, 2015, 4(3):915-920. [7] YANAMASHETTI G, SURYANARAYANA G K, MUKHERJEE R. Development of flow over blunt-nosed slender bodies at transonic mach numbers[J]. Journal of Physics:Conference Series, 2017, 822(1):012071. [8] MAKHIJA J, REDDY D S K, RISHABH. Numerical simulation of flow field over slender bodies at transonic mach number and low angle of attacks[J]. IOP Conference Series:Materials Science and Engineering, 2020, 912(4):042047. [9] ZHU X C, YU X J, HONG Y. Aerodynamic characteristics of fairing separation at initial opening angle[C]//Proceedings of the 1st International Conference on Mechanical Engineering and Material Science. Amsterdam, Netherlands:Atlantis Press, 2012, 12:613-616. [10] LIU Y J, LI Z, SUN Q, et al. Separation dynamics of large-scale fairing section:A fluid-structure interaction study[J]. Proceedings of the Institution of Mechanical Engineers, Part G:Journal of Aerospace Engineering, 2013, 227(11):1767-1779. [11] 张小伟, 王延荣, 谢胜百, 等. 弹性整流罩分离的流固耦合仿真方法[J]. 北京航空航天大学学报, 2009, 35(8):976-979, 995. ZHANG X W, WANG Y R, XIE S B, et al. Fluid-Structure interaction method on numerical simulation of elastic fairing separation[J]. Journal of Beijing University of Aeronautics and Astronautics, 2009, 35(8):976-979, 995. (in Chinese) [12] 祝学军, 卜奎晨, 王浩, 等. 采用优化加点Kriging模型的助推火箭残骸安全区预示方法[J]. 国防科技大学学报, 2020, 42(2):121-126. ZHU X J, BU K C, WANG H, et al. Prediction method for booster rocket's debris safety control zone based on infill-sampling Kriging model[J]. Journal of National University of Defense Technology, 2020, 42(2):121-126. (in Chinese) [13] 王景国, 卞韩城, 陈学林, 等. CZ-2F火箭整流罩残骸落点预报方法研究[J]. 载人航天, 2014, 20(5):457-460. WANG J G, BIAN H C, CHEN X L, et al. Research on impact point prediction methods of CZ-2F rocket fairing debris[J]. Manned Spaceflight, 2014, 20(5):457-460. (in Chinese) [14] 李耀民. 卫星整流罩设计与"三化"[J]. 导弹与航天运载技术, 1999(2):1-11. LI Y M. Satellite fairing design and systematization, standardization and combination[J]. Missiles and Space Vehicles, 1999(2):1-11. (in Chinese) [15] SELTNER P M, WILLEMS S, GVLHAN A, et al. Aerodynamics of inclined cylindrical bodies free-flying in a hypersonic flowfield[J]. Experiments in Fluids, 2021, 62(9):182. [16] KALUGIN V T, LUTSENKO A Y, NAZAROVA D K. Aerodynamic characteristics of thin cylindrical and conical shells in the incompressible flow[J]. Russian Aeronautics, 2018, 61(3):404-411. [17] KALUGIN V T, LUTSENKO A Y, NAZAROVA D K. Numerical and physical simulation of supersonic flow aroundshells[J]. AIP Conference Proceedings, 2021, 2318(1):110021.
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