TY - JOUR

T1 - Assessment of a one-dimensional finite element charring ablation material response model for phenolic-impregnated carbon ablator

AU - Wang, Yeqing

AU - Risch, Timothy K.

AU - Koo, Joseph H.

N1 - Funding Information:
This work was supported by the Air Force Research Laboratory (AFRL) under contract no. FA8651-08-D-0108 and task order no. 42. Any opinions, findings, conclusions, or recommendations expressed in this work are those of the authors and do not necessarily reflect the views of the AFRL. Y. Wang also thanks Dr. Crystal L. Pasiliao (AFRL/RW) and Prof. David W. Hahn (University of Florida) for their support in this research.
Funding Information:
This work was supported by the Air Force Research Laboratory (AFRL) under contract no. FA8651-08-D-0108 and task order no. 42. Any opinions, findings, conclusions, or recommendations expressed in this work are those of the authors and do not necessarily reflect the views of the AFRL. Y. Wang also thanks Dr. Crystal L. Pasiliao (AFRL/RW) and Prof. David W. Hahn (University of Florida) for their support in this research.
Publisher Copyright:
© 2019 Elsevier Masson SAS

PY - 2019/8

Y1 - 2019/8

N2 - In this study, mathematical formulations to model charring ablation problems were numerically implemented using finite element analysis (FEA) with ABAQUS, which account for the material decomposition and progressive surface removal in the heat conduction and the surface energy balance equations. FEA was performed for a one-dimensional model to predict the temperature and ablation histories of a phenolic-impregnated carbon ablator sample (i.e., a common heat shield material for hypersonic vehicles and spacecraft) subjected to oxy-acetylene torch flame (i.e., 0.8 SLPM acetylene gas to 2.7 SLPM oxygen gas). The recovery enthalpy and convective heat transfer coefficient for the ablation model were calculated based on gas compositions and two assumed surface conditions (i.e., equilibrium and frozen). Simulations using the calculated recovery enthalpy and convective heat transfer coefficient resulted in a recession rate of 6.38 times (equilibrium) and 14.08 times (frozen) higher than the experimental data, despite fair agreement of the surface temperature. In addition, the effect of the heat transfer coefficient was investigated through a steady-state ablation analysis. The results of the analysis indicate that there is not one single value for the heat transfer coefficient that would allow the prediction to match both measured recession rate and surface temperature. Possible reasons for such an inconsistency are provided and discussed.

AB - In this study, mathematical formulations to model charring ablation problems were numerically implemented using finite element analysis (FEA) with ABAQUS, which account for the material decomposition and progressive surface removal in the heat conduction and the surface energy balance equations. FEA was performed for a one-dimensional model to predict the temperature and ablation histories of a phenolic-impregnated carbon ablator sample (i.e., a common heat shield material for hypersonic vehicles and spacecraft) subjected to oxy-acetylene torch flame (i.e., 0.8 SLPM acetylene gas to 2.7 SLPM oxygen gas). The recovery enthalpy and convective heat transfer coefficient for the ablation model were calculated based on gas compositions and two assumed surface conditions (i.e., equilibrium and frozen). Simulations using the calculated recovery enthalpy and convective heat transfer coefficient resulted in a recession rate of 6.38 times (equilibrium) and 14.08 times (frozen) higher than the experimental data, despite fair agreement of the surface temperature. In addition, the effect of the heat transfer coefficient was investigated through a steady-state ablation analysis. The results of the analysis indicate that there is not one single value for the heat transfer coefficient that would allow the prediction to match both measured recession rate and surface temperature. Possible reasons for such an inconsistency are provided and discussed.

KW - Charring ablation

KW - Finite element analysis (FEA)

KW - Hypersonic re-entry

KW - Oxy-acetylene torch

KW - Phenolic-impregnated carbon ablator

KW - Pyrolysis

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U2 - 10.1016/j.ast.2019.05.039

DO - 10.1016/j.ast.2019.05.039

M3 - Article

AN - SCOPUS:85065870645

SN - 1270-9638

VL - 91

SP - 301

EP - 309

JO - Zeitschrift fur Flugwissenschaften und Weltraumforschung

JF - Zeitschrift fur Flugwissenschaften und Weltraumforschung

ER -