The critical tube diameter and critical energy for direct initiation of detonation in C2H2/N2O/Ar mixtures
The critical tube diameter and critical energy for direct initiation of detonation in C2H2/N2O/Ar mixtures
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DOI：
10.1016/j.combustflame.2012.06.010
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发表时间：
2012-09
影响因子：
4.4
通讯作者：
Bo Zhang;H. D. Ng;John H. S. Lee
中科院分区：
文献类型：
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作者：
Bo Zhang;H. D. Ng;John H. S. Lee
本研究测量了不同初始条件下C2H2/N2O/Ar混合物的动态爆轰参数，即直接起爆临界管径和临界能。利用化学动力学、Konnov机制和实验测量数据，建立了计算C2H2/N2O/Ar爆轰临界管径的简单关系式：dc=594.8φ0.623(1-XAr)0.2176(p/po)-0.0246ΔIwhich，该关系式适用于初始压力为50 ~ 130kPa，当量比为0.625 ~ 2.5的化学计量混合物，以及在常压下氩气最大稀释率为50%的化学计量混合物。将该关联函数与基于简单做功概念的理论模型相结合，可以预测直接起爆的临界能；理论预测结果与实验测量的临界能吻合较好。为了评估爆轰敏感性，将C2H2/N2O/Ar混合物与H2/N2O/Ar混合物中直接起爆的临界能量结果进行了比较[Zhang等人，Int.]。[j].氢能工程学报，2011(5):557 - 557。结果表明，在相同的初始条件下，C2H2/N2O/Ar比H2/N2O/Ar更敏感。化学动力学计算也定性地支持了这一点，表明C2H2/N2O/Ar混合物的ZND感应长度尺度相对小于H2/N2O/Ar混合物。最后，通过对比C2H2/N2O/Ar和C2H2/O2/Ar混合物的临界能，研究了氧化剂对爆轰灵敏度的影响。结果表明，C2H2/N2O/Ar混合物比C2H2/O2/Ar混合物需要更高的能量才能成功引发球形爆轰，结果与ZND感应长度分析结果基本一致。
In this study, the dynamic detonation parameters, namely, the critical tube diameter and critical energy for direct initiation, of C2H2/N2O/Ar mixtures were measured at various initial conditions. Using chemical kinetics with the Konnov mechanism and experimental measured data, a simple correlation to evaluate the critical tube diameter of C2H2/N2O/Ar detonation is developed, given by dc=594.8φ0.623(1-XAr)0.2176(p/po)-0.0246ΔIwhich is applicable for stoichiometric mixtures with initial pressures ranging from 50 to 130kPa, equivalence ratios from 0.625 to 2.5 and stoichiometric mixtures with maximum percentage of argon dilution up to 50% at the atmospheric pressure. By combining this correlation function with a theoretical model based on a simple work done concept, the critical energy for direct blast initiation can be predicted; and the theoretical predictions are found to be in good agreement with the critical energy measured experimentally. To assess the detonation sensitivity, the critical energy results for direct initiation of detonation in C2H2/N2O/Ar mixtures are compared with those in H2/N2O/Ar mixtures [Zhang et al., Int. J. Hydrogen Energy 39 (2011) 5707–5716]. The results indicate that C2H2/N2O/Ar is more sensitive than H2/N2O/Ar at the same initial conditions. This is also supported qualitatively by the chemical kinetic calculation which shows that the ZND induction length scale for C2H2/N2O/Ar is relatively smaller than that of H2/N2O/Ar mixture. Lastly, the effect of the oxidizer on the detonation sensitivity is studied by comparing the critical energy between C2H2/N2O/Ar and C2H2/O2/Ar mixture. It is found that a higher energy is required to successfully initiate a spherical detonation in C2H2/N2O/Ar than in C2H2/O2/Ar mixtures and equivalently, the results agree qualitatively with the ZND induction length analysis.