TY - JOUR
T1 - Effect of 2-step energy release on direct detonation initiation by a point energy source in a rich H2–NO2/N2O4 mixture
AU - Faghih, Mahdi
AU - Mével, Rémy
AU - He, Yizhuo
AU - Chen, Zheng
N1 - Funding Information:
Mahdi Faghih was supported by the Shui Mu posdoctoral scholarship of Tsinghua University. Rémy Mével was supported by a start-up fund of the Center for Combustion Energy of Tsinghua University, the Thousand Young Talents Program of China, and the 1000 Young Talents Matching Fund of Tsinghua University. Yizhuo He was funded by China Postdoctoral Science Foundation (grant number 2019M650674).
Funding Information:
Mahdi Faghih was supported by the Shui Mu posdoctoral scholarship of Tsinghua University. R?my M?vel was supported by a start-up fund of the Center for Combustion Energy of Tsinghua University, the Thousand Young Talents Program of China, and the 1000 Young Talents Matching Fund of Tsinghua University. Yizhuo He was funded by China Postdoctoral Science Foundation (grant number 2019M650674).
Publisher Copyright:
© 2020 The Combustion Institute
PY - 2020/12
Y1 - 2020/12
N2 - In the present study, direct detonation initiation by a point energy source in a rich H2–NO2/N2O4–Ar mixture has been investigated using high-resolution one-dimensional numerical simulations performed with detailed chemistry. In particular, the effect of the 2-step energy release profile on the critical initiation energy and the dynamics of the failure process has been studied for the first time. Three reduced reaction models exhibiting a similar first step of energy release but a second step of different strengths have been employed. As the second step of heat release is strengthened, the overall behavior gets closer and closer to a 1-step process. It was found that the critical initiation energy for successful detonation initiation decreases as the second step of heat release is strengthened and the width of the overall heat release pulse is reduced. This feature has been investigated by studying the competition between chemical heat release and unsteadiness along the path of Lagrangian particles. The decrease of the critical initiation energy for stronger second step of heat release seems to be a result of the decrease of the sensitivity of this second step to unsteadiness-induced quenching behind a decaying shock wave. In view of the present results and previous experimental observations on propagating and diffracting detonation in H2–NO2/N2O4(–Ar) mixtures, it seems that the 2-step energy release presenting the specific characteristics observed in rich H2–NO2/N2O4(–Ar) mixtures, i.e. a strong and rapid first step and a weak and slow second step, constitutes a feature which is not essential for detonation propagation but makes detonation direct initiation and transmission to open space more difficult.
AB - In the present study, direct detonation initiation by a point energy source in a rich H2–NO2/N2O4–Ar mixture has been investigated using high-resolution one-dimensional numerical simulations performed with detailed chemistry. In particular, the effect of the 2-step energy release profile on the critical initiation energy and the dynamics of the failure process has been studied for the first time. Three reduced reaction models exhibiting a similar first step of energy release but a second step of different strengths have been employed. As the second step of heat release is strengthened, the overall behavior gets closer and closer to a 1-step process. It was found that the critical initiation energy for successful detonation initiation decreases as the second step of heat release is strengthened and the width of the overall heat release pulse is reduced. This feature has been investigated by studying the competition between chemical heat release and unsteadiness along the path of Lagrangian particles. The decrease of the critical initiation energy for stronger second step of heat release seems to be a result of the decrease of the sensitivity of this second step to unsteadiness-induced quenching behind a decaying shock wave. In view of the present results and previous experimental observations on propagating and diffracting detonation in H2–NO2/N2O4(–Ar) mixtures, it seems that the 2-step energy release presenting the specific characteristics observed in rich H2–NO2/N2O4(–Ar) mixtures, i.e. a strong and rapid first step and a weak and slow second step, constitutes a feature which is not essential for detonation propagation but makes detonation direct initiation and transmission to open space more difficult.
KW - 2-step energy release
KW - Direct detonation initiation
KW - One-dimensional numerical simulation
UR - http://www.scopus.com/inward/record.url?scp=85090592503&partnerID=8YFLogxK
U2 - 10.1016/j.combustflame.2020.08.036
DO - 10.1016/j.combustflame.2020.08.036
M3 - Article
AN - SCOPUS:85090592503
SN - 0010-2180
VL - 222
SP - 317
EP - 325
JO - Combustion and Flame
JF - Combustion and Flame
ER -