Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
Simulation of Hypersonic Flows in Thermochemical Non-Equilibrium Conditions: Influence of the Control Temperature of Park's Two-Temperature Model in the Flow Behavior
Submission Author:
Gibson De Marchi Poltronieri , SP
Co-Authors:
Gibson De Marchi Poltronieri, Farney Moreira, João Luiz F. Azevedo
Presenter: Gibson De Marchi Poltronieri
doi://10.26678/ABCM.COBEM2023.COB2023-0144
Abstract
The reentry procedure plays a critical role in aerospace missions to guarantee the safety and integrity of the vehicle. The hypersonic reentry flow imposes severe conditions on the body with high temperature and pressure gradients. Moreover, high-temperature gas phenomena, such as thermodynamic and chemical non-equilibrium, become more present with higher values of freestream Mach number. One method developed to account for the non-equilibrium phenomena in the calculations of dissociation rates is the two-temperature model described by Park. This model couples the translational and rotational temperatures in one temperature mode, and the vibrational and electronic temperatures in another temperature mode. The dissociation rates are calculated using the so-called control temperature as a function of the two temperature modes. The present work aims to broaden understanding of the influence of the parameters chosen for computing the control temperature in the Park two-temperature model. The work uses an in-house developed code that solves the Navier-Stokes equations using a finite volume approach. The inviscid fluxes across cell faces are discretized using a modified Steger-Warming flux vector splitting scheme, which switches to the original Steger-Warming scheme in the vicinity of shock waves. A second-order reconstruction of the inviscid fluxes is implemented. The calculation of the viscous fluxes uses a second-order centered scheme that combines properties at cell centers and nodes. The time integration is performed by a line implicit method. Numerical simulations for the FIRE II reentry capsule are addressed in the present work. Reacting hypersonic flow conditions with thermodynamic non-equilibrium are considered. Earth's atmosphere is described by an 11-species chemical model. Freestream conditions are based on actual discrete points along the FIRE II reentry trajectory for which experimental data are available. For each chosen test case, simulations with different parameters in the definition of the control temperature for the Park two-temperature model are analyzed. The present investigation demonstrates that changes on the weight factors for the control temperature calculation may result in significant changes on the shock wave position, on the composition of the gas mixture in the non-equilibrium region, and on the maximum values observed for the individual translational-rotational and vibrational-electronic temperature modes.
Keywords
Hypersonic Flow, CFD, Thermodynamic non-equilibrium, Chemical non-equilibrium, Temperature Models
