Numerical Analysis on the Aerodynamic Coefficients of an Ejection Seat System at Subsonic Speed

Md. Mahbubur  Rahman; Ved  Prakash; Sunil  Chandel; D. G.  Thakur

doi:10.6180/jase.202410_27(10).0007

Numerical Analysis on the Aerodynamic Coefficients of an Ejection Seat System at Subsonic Speed

Md. Mahbubur RahmanThis email address is being protected from spambots. You need JavaScript enabled to view it., Ved Prakash, Sunil Chandel, and D. G. Thakur

Department of Mechanical Engineering, Defence Institute of Advanced Technology (DU), Girinagar, Pune - 411025, India

Received: July 8, 2023
Accepted: November 24, 2023
Publication Date: December 29, 2023

Copyright The Author(s). This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are cited.

Download Citation: ||https://doi.org/10.6180/jase.202410_27(10).0007

In the present study, a 3-D analysis of the aerodynamic coefficients of the ejection seat system is performed using Computational Fluid Dynamics (CFD) software ANSYS-Fluent. For this investigation, an unstructured grid of polyhedral cells is created. The Reynolds Averaged Navier-Stokes (RANS) equations are solved with the standard k − ε turbulence model to calculate the aerodynamic coefficients. Before this analysis, a simple blunt bodylike sphere is analyzed to understand the physics and the boundary conditions suitable for external flow aerodynamics at subsonic speed.The drag coefficient (C_d) on the sphere is calculated and matched with the experimental results at Mach number (Ma) = 0.6, 0.46, and 0.33 . Later on, for validation purposes, the analysis of the ejection seat system is performed at Ma = 0.6. Finally, the aerodynamic coefficients are measured for angle of attack (α) = −75^◦, −60^◦, −45^◦, −30^◦, −15^◦, 0^◦, 15^◦, 30^◦, 45^◦, 60^◦, and 75^◦ at Ma = 0.7 and yaw angle (β) = 0^◦ . It is observed that with the increase of α the magnitude of the axial force coefficient (C_x) is increasing up to α = −15^◦ and after that, it decreases with the increase of α. The normal force coefficient (C_z) is decreasing with the increase of α and at α = −75^◦ , the maximum value of the C_z is found. The minimum value of the pitching moment coefficient (C_m) is found at α = 0^◦, whereas the value of the Cm increases as the α changes from 0^◦.

Keywords: Blunt body; sphere; ejection seat system; aerodynamic coefficients; Mach number; angle of attack

[1] S. M. Burk. Wind-tunnel investigation of aerodynamic characteristics of a 1/2-scale model of an ejection seat with a rigid-wing recovery system. National Aeronautics and Space Administration, 1970.
[2] D. E. Reichenau. Aerodynamic Characteristics of an Ejection Seat Escape System with a Stabilization Parachute at Mach Numbers from 0.3 Through 1.2. 72. 51. Arnold Engineering Development Center, Air Force Systems Command, United . . ., 1972.
[3] B. J. White. Aeromechanical Properties of Ejection Seat Escape Systems. NTIS, 1974.
[4] F. W. Hawker, (1979) “Wind Tunnel Test of ACES II Ejection Seat with Anthropometric Dummy in Asymmetric Configurations" AMRL-TR 78: 1O8.
[5] C. Dehua, W. Jinjun, W. Wenhua, and C. Liyan, (2006) “Ejection seat test techniques in a high-speed wind tunnel" Journal of aircraft 43(5): 1593–1596. DOI: 10.2514/1. 20160.
[6] S. Caruso and M. Mendenhall. “Computational analysis of high-speed ejection seats”. In: 30th Aerospace Sciences Meeting and Exhibit. 1992, 403.
[7] S. Habchi, A. Przekwas, T. Marquette, and P. Ayoub, (1992) “CFD Analysis of Ejection Seat Escape Systems" SAE Transactions: 1566–1579. DOI: 10.4271/921924.
[8] G. Hufford and S. Habchi. “Validation of CFD methodology for ejection seat applications”. In: 32nd Aerospace Sciences Meeting and Exhibit. 1994, 751.
[9] S. Habchi and G. Hufford. “Transient simulation of turbulent flow over blunt bodies (ejection seat configurations)”. In: 13th Applied Aerodynamics Conference. 1995, 1837.
[10] D. Chen, W. Wu, J.-J. Wang, and Y. Huang, (2007) “Investigation on the aerodynamic performance of an ejection seat" The Aeronautical Journal 111(1120): 373–380. DOI: 10.1017/S0001924000004620.
[11] C. Tyler and M. Burkinshaw. “Computational Study of Aircraft Forebody Impact on Aerodynamic Forces Experienced During Pilot Ejection”. In: 48th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition, 313.
[12] Y. Zhu, X. Zhao, and S. Zhang. “Computational studies of aircraft Life-Support systems”. In: 49th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition. 2011, 1045.
[13] J. L. Tian and L. Chen, (2012) “Aerodynamic Characteristics Numerical Simulation of the Protective Device of Ejection Seat" Applied Mechanics and Materials 229: 1811–1814. DOI: 10.4028/www.scientific.net/AMM.229-231.1811.
[14] H. Guan, Y. Zhu, X. Zhao, and S. Zhang. “Aerodynamic Characteristics of Ejection Seat and Occupant”. In: 51st AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition. 2013, 386.
[15] N. S. Reddy, K. Vishwanath, V. Satheesha, R. Thejaraju, N. K. Raj, M. Manoj, H. Goutham, B. Manjunatha, et al., (2021) “Study on heat transfer and pressure drop in tube-in-tube helical heat exchanger" Journal of Applied Science and Engineering 24(4): 635–642. DOI: 10.6180/jase.202108_24(4).0019.
[16] Z. Wu, Z. Xie, P. Wang, W. Ding, et al., (2020) “Aerodynamic drag performance analysis of different types of high-speed train pantograph fairing" Journal of Applied Science and Engineering 23(3): 509–519. DOI: 10.6180/jase.202009_23(3).0015.
[17] S. S. Rajan, M. Santhoshkumar, N. Lakshmanan, S. N. Pillai, M. Paramasivam, et al., (2009) “CFD analysis and wind tunnel experiment on a typical launch vehicle model" Journal of Applied Science and Engineering 12(3): 223–229.
[18] M. M. Rahman and A. Islam. “Numerical study of convective heat transfer for turbulent flow in corrugated tube using Al2O3-water nanofluid”. In: AIP Conference Proceedings. 2121. 1. AIP Publishing. 2019. DOI: 10.1063/1.5115916.
[19] K. L. Goin and W. Lawrence, (1968) “Subsonic drag of spheres at Reynolds numbers from 200 to 10,000." AIAA Journal 6(5): 961–962. DOI: 10.2514/3.4648.
[20] T. Ma. Nagata, T. Nonomura, S. Takahashi, Y. Mizuno, and K. Fukuda, (2016) “Investigation on subsonic to supersonic flow around a sphere at low Reynolds number of between 50 and 300 by direct numerical simulation" Physics of Fluids 28(5): DOI: 10.1063/1.4947244.