Numerical study on the effect of temperature and scale ratio on aerodynamics of maglev trains moving dynamically in a vacuum transportation system

Abstract

The airflow around a vacuum tube maglev train operating at high speeds is complex. In addition, the effect of relevant parameters in such a transportation system on aerodynamic characteristics is crucial in the design and safety of the system. A three-dimensional (3D) vacuum tube train model is established based on a vacuum tube test platform for rail transit. The effects of the initial ambient temperature and scale ratio on the aerodynamic characteristics are analyzed during the whole operational process in this study. The results mainly focus on each process’s variations in the shock waves, choked flow, and drag. During acceleration, shock wave generation is advanced or delayed under different system parameters, which vary the aerodynamic drag. While the train runs at a constant speed, the time that a standard shock is generated and the length of the choked flow differ under the effects of the varying system parameters. In braking, the disappearance of shock waves and reflections of the expansion wave suddenly decreases the aerodynamic drag either earlier or later due to the varying system parameters.

Keywords

vacuum tube transportation / aerodynamics / shock wave / choked flow / drag

References

[1] HuX, WanY-c, MeiY-g, et al.. Wake dynamics and three-dimensional shock wave morphology in an evacuated tube transportation system under choked flow via proper orthogonal decomposition with domain partitioning [J]. Physics of Fluids, 2025, 374046126.

[2] HuangZ-d, PengC, ChenZ-w, et al.. Compressible effects of a supersonic evacuated tube maglev train at various Mach numbers [J]. Physics of Fluids, 2024, 3612126126.

[3] ZHANG Wei-hua, DENG Zi-gang, BI Hai-quan, et al. Research review and reflections on ultra-high-speed rail transit in low-vacuum environments [J]. Electric Drive for Locomotives, 2025(1): 1–13. DOI: https://doi.org/10.13890/j.issn.1000-128X.2025.01.109. (in Chinese)

[4] SeoY, ChoM, KimD H, et al.. Experimental analysis of aerodynamic characteristics in the Hyperloop system [J]. Aerospace Science and Technology, 2023, 137108265.

[5] MirzaM O, AliZ. Numerical analysis of aerodynamic characteristics of multi-pod hyperloop system [J]. Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering, 2023, 237(8): 1727-1750.

[6] JanzenR. TransPod ultra-high-speed tube transportation: Dynamics of vehicles and infrastructure [J]. Procedia Engineering, 2017, 199: 8-17.

[7] LiT, SongJ-y, ZhangX-h, et al.. Theoretical and numerical studies on compressible flow around a subsonic evacuated tube train [J]. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, 2022, 236(15): 8261-8271

[8] ZhongS, YangM-z, QianB-s, et al.. Temporal evolution of flow field structure for vehicles accelerating in evacuated tube transportation system [J]. Physics of Fluids, 2023, 352025117.

[9] HouZ-h, ZhuY-j, BoJ-l, et al.. A quasi-one-dimensional study on global characteristics of tube train flows [J]. Physics of Fluids, 2022, 342026104.

[10] YuQ-j, YangX-f, NiuJ-q, et al.. Theoretical and numerical study of choking mechanism of fluid flow in Hyperloop system [J]. Aerospace Science and Technology, 2022, 121107367.

[11] BiH-q, LeiB. Aerodynamic characteristics of evacuated tube high-speed train [M]. International Conference on Transportation Engineering, 200937363741

[12] LangA J, ConnollyD P, deB G, et al.. A review of hyperloop aerodynamics [J]. Computers & Fluids, 2024, 273106202.

[13] LangA J, ConnollyD P, deB G, et al.. Benchmark problems for simulating hyperloop aerodynamics [J]. Physics of Fluids, 2024, 3610106116.

[14] LeT T G, KimJ, JangK S, et al.. Numerical study on the influence of the nose and tail shape on the aerodynamic characteristics of a Hyperloop pod [J]. Aerospace Science and Technology, 2022, 121107362.

[15] JangK S, LeT T G, KimJ, et al.. Effects of compressible flow phenomena on aerodynamic characteristics in Hyperloop system [J]. Aerospace Science and Technology, 2021, 117106970.

[16] SuiY, NiuJ-q, YuQ-j, et al.. Numerical analysis of the aerothermodynamic behavior of a Hyperloop in choked flow [J]. Energy, 2021, 237121427.

[17] KimJ, LeeC, LeT T G, et al.. Effects of eccentricity in tube-pod arrangements on hyperloop aerodynamics [J]. International Journal of Mechanical Sciences, 2024, 279109505.

[18] MaJ-q, ZhouD-j, ZhaoL-f, et al.. The approach to calculate the aerodynamic drag of maglev train in the evacuated tube [J]. Journal of Modern Transportation, 2013, 21(3): 200-208.

[19] KimT K, KimK H, KwonH B. Aerodynamic characteristics of a tube train [J]. Journal of Wind Engineering and Industrial Aerodynamics, 2011, 99(12): 1187-1196.

[20] LiuJ-L, ZhangJ-Y, ZhangW-h. Impacts of pressure, blockage ratio and speed on aerodynamic drag force of high-speed trains [J]. Journal of Vacuum Science & Technology A, 2014, 34(1): 10-15

[21] HuangZ-d, LiangX-f, ChangN. Numerical analysis of train aerodynamic drag of vacuum tube traffic [J]. Journal of Mechanical Engineering, 2019, 55(8): 165-172. in Chinese)

[22] ZhouP, ZhangJ, LiT, et al.. Effect of initial ambient temperature on aerodynamic characteristics of highspeed train in an evacuated tube [J]. Acta Aerodynamica Sinica, 2021, 39(5): 181-190(in Chinese)

[23] ZhouP, ZhangJ-y. Aerothermal mechanisms induced by the super high-speed evacuated tube maglev train [J]. Vacuum, 2020, 173109142.

[24] SuiY, YuQ-j, NiuJ-q, et al.. Flow characteristics and aerodynamic heating of tube trains in choked/unchoked flow: A numerical study [J]. Journal of Thermal Science, 2023, 32(4): 1421-1434.

[25] ZhangX-h, LiT, ZhangJ-y, et al.. Aerodynamic choked flow and shock wave phenomena of subsonic evacuated tube train [J]. Journal of Mechanical Engineering, 2021, 57(4): 182-190. in Chinese)

[26] ZhouP, ZhangJ-y, LiT, et al.. Numerical study on wave phenomena produced by the super high-speed evacuated tube maglev train [J]. Journal of Wind Engineering and Industrial Aerodynamics, 2019, 190: 61-70.

[27] BaoS-j, HuX, WangJ-k, et al.. Numerical study on the influence of initial ambient temperature on the aerodynamic heating in the tube train system [J]. Advances in Aerodynamics, 2020, 2128.

[28] ZhouP, ZhangJ-y, LiT. Effects of blocking ratio and Mach number on aerodynamic characteristics of the evacuated tube train [J]. International Journal of Rail Transportation, 2020, 8(1): 27-44.

[29] BiH-q, WangZ-h, WangH-l, et al.. Aerodynamic phenomena and drag of a maglev train running dynamically in a vacuum tube [J]. Physics of Fluids, 2022, 349096111.

[30] NiuJ-q, SuiY, YuQ-j, et al.. Effect of acceleration and deceleration of a capsule train running at transonic speed on the flow and heat transfer in the tube [J]. Aerospace Science and Technology, 2020, 105105977.

[31] GarbarukA, ShurM, StreletsM, et al.. Numerical study of wind-tunnel walls effects on transonic airfoil flow [J]. AIAA Journal, 2003, 41(6): 1046-1054.

RIGHTS & PERMISSIONS

Central South University