TY - JOUR
T1 - Data-Inspired and Physics-Driven Model Reduction for Dissociation
T2 - Application to the O2+ O System
AU - Venturi, S.
AU - Sharma, M. P.
AU - Lopez, B.
AU - Panesi, M.
N1 - Funding Information:
The work was supported by the Air Force Office of Scientific Research no. FA9550-18-1-0388 with Program Office Dr. Ivett Leyva. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of the AFOSR or the U.S. government. The authors would like to thank Dr. A. Sahai (NASA Ames Research Center) for the useful discussions about reduced-order modeling.
Funding Information:
The work was supported by the Air Force Office of Scientific Research no. FA9550-18-1-0388 with Program Office Dr. Ivett Leyva. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied of the AFOSR or the U.S. government. The authors would like to thank Dr. A. Sahai (NASA Ames Research Center) for the useful discussions about reduced-order modeling.
Publisher Copyright:
© 2020 American Chemical Society.
PY - 2020/10/15
Y1 - 2020/10/15
N2 - This work presents an in-depth discussion on the nonequilibrium dissociation of O2 molecules colliding with O atoms, combining quasi-classical trajectory calculations, master equation, and dimensionality reduction. A rovibrationally resolved database for all of the elementary collisional processes is constructed by including all nine adiabatic electronic states of O3 in the QCT calculations. A detailed analysis of the ab initio data set reveals that for a rovibrational level, the probability of dissociating is mostly dictated by its deficit in internal energy compared to the centrifugal barrier. Because of the assumption of rotational equilibrium, the conventional vibrational-specific calculations fail to characterize such a dependence. Based on this observation, a new physics-based grouping strategy for application to coarse-grained models is proposed. By relying on a hybrid technique made of rovibrationally resolved excitation coupled to coarse-grained dissociation, the new approach is compared to the vibrational-specific model and the direct solution of the rovibrational state-to-state master equation. Simulations are performed in a zero-dimensional isothermal and isochoric chemical reactor for a wide range of temperatures (1500-20,000 K). The study shows that the main contribution to the model inadequacy of vibrational-specific approaches originates from the incapability of characterizing dissociation, rather than the energy transfers. Even when constructed with only twenty groups, the new reduced-order model outperforms the vibrational-specific one in predicting all of the QoIs related to dissociation kinetics. At the highest temperature, the accuracy in the mole fraction is improved by 2000%.
AB - This work presents an in-depth discussion on the nonequilibrium dissociation of O2 molecules colliding with O atoms, combining quasi-classical trajectory calculations, master equation, and dimensionality reduction. A rovibrationally resolved database for all of the elementary collisional processes is constructed by including all nine adiabatic electronic states of O3 in the QCT calculations. A detailed analysis of the ab initio data set reveals that for a rovibrational level, the probability of dissociating is mostly dictated by its deficit in internal energy compared to the centrifugal barrier. Because of the assumption of rotational equilibrium, the conventional vibrational-specific calculations fail to characterize such a dependence. Based on this observation, a new physics-based grouping strategy for application to coarse-grained models is proposed. By relying on a hybrid technique made of rovibrationally resolved excitation coupled to coarse-grained dissociation, the new approach is compared to the vibrational-specific model and the direct solution of the rovibrational state-to-state master equation. Simulations are performed in a zero-dimensional isothermal and isochoric chemical reactor for a wide range of temperatures (1500-20,000 K). The study shows that the main contribution to the model inadequacy of vibrational-specific approaches originates from the incapability of characterizing dissociation, rather than the energy transfers. Even when constructed with only twenty groups, the new reduced-order model outperforms the vibrational-specific one in predicting all of the QoIs related to dissociation kinetics. At the highest temperature, the accuracy in the mole fraction is improved by 2000%.
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U2 - 10.1021/acs.jpca.0c04516
DO - 10.1021/acs.jpca.0c04516
M3 - Article
C2 - 32886505
AN - SCOPUS:85093539395
SN - 1089-5639
VL - 124
SP - 8359
EP - 8372
JO - Journal of Physical Chemistry A
JF - Journal of Physical Chemistry A
IS - 41
ER -