Effects of inert gas jet on the transition from deflagration to detonation in a stoichiometric methane-oxygen mixture
Effects of inert gas jet on the transition from deflagration to detonation in a stoichiometric methane-oxygen mixture
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惰性气体射流对化学计量甲烷-氧气混合物中从爆燃到爆炸转变的影响
DOI：
10.1016/j.fuel.2020.119237
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发表时间：
2021-02
期刊：
影响因子：
7.4
通讯作者：
Wang fuxing
中科院分区：
文献类型：
--
作者：
Cheng Jun;Zhang Bo;Hoi Dick Ng;Liu Hong;Wang fuxing
爆震是一种增强高动量和热力学效率的高能燃烧方式，已应用于爆震发动机，如脉冲爆震发动机（PDE）和旋转爆震发动机（RDE），它们已成为潜在的航空航天推进设备。最近，流体射流交叉流（JICF）已被实验和数值证明可以加速爆燃到爆炸的转变（DDT）过程。尽管如此，之前的大多数研究都集中在使用可燃混合物或氧气的喷气机上，这可能会给爆震发动机中的湍流产生系统带来额外的风险。本研究采用更安全可控的惰性气体（即Ar）进行JICF，通过实验研究氩气喷射作为增强方法对化学计量甲烷-氧气混合物中DDT的促进作用。系统地研究了局部氩气浓度、湍流强度和注射位置对 DDT 过程的影响。还进行了二维数值模拟以阐明注入演化的细节。实验结果表明，吹氩产生的湍流仅在快爆燃状态下才能促进火焰加速和爆轰的发生。在湍流强度较高时，通过提高射流喷射压力和缩短喷射时间，增强效果更加突出。注入时间过长会增加氩气的局部浓度，从而导致抑制 DDT 发生的不利影响。在最初的层流火焰加速期间（称为慢爆燃状态），没有观察到氩气喷射对 DDT 的增强。通过对氩气射流的流动结构进行数值观察，涡流特征增强了反应物和产物之间的传输和混合。反应行波与射流结构之间的相互作用进一步引起湍流，从而加速化学反应速率。随着时间的推移，注入的氩气会大量夹带并稀释周围的可燃混合物，并抑制 DDT。此外，提出了一种新的无量纲准则和特征参数Turcare，定量分析了火焰传播的主导机制以及DDT作为惰性射流的初始阶段。
Detonation is an energetic combustion mode augmenting high flow momentum and thermodynamic efficiency, it has been applied in detonation engines, such as pulse detonation engines (PDEs) and rotating detonation engines (RDEs), they have become potential aerospace propulsion equipment. Recently, fluidic jet-in-cross flow (JICF) has been demonstrated experimentally and numerically that can accelerate the deflagration-to-detonation transition (DDT) process. Nonetheless, most of previous studies focused on the jets using combustible mixture or oxygen, which may bring additional risk for turbulence-generated system in detonation engines. In this study, a more safe and controllable inert gas (i.e., Ar) is applied for JICF, experiments are carried out to investigate effects of argon jet as an enhancement method on promoting the DDT in a stoichiometric methane-oxygen mixture. The effects of local argon concentration, turbulence intensity and injection position on the DDT process are systematically examined. Two-dimensional numerical simulations are also performed to elucidate the details of the injection evolution. The experimental results show that turbulence generated by the argon injection can promote flame acceleration and the onset of detonation only in the fast deflagration regime. The enhancing effect is more prominent at higher turbulence intensity by increasing jet injection pressure and shorter injection time. Too long injection duration increases argon local concentration that leads to an adverse effect prohibiting the DDT occurrence. During the initial laminar flame acceleration, referred to as the slow deflagration regime, no enhancement by the argon jet on DDT can be observed. By looking numerically at the flow structure of the argon jet, the vortical features enhance the transport and mixing between reactants and products. The interaction between the reactive travelling wave and the jet structure further induces turbulence and thus accelerates the chemical reaction rate. With the time elapsed, the injected argon entrains largely and dilutes the ambient combustible mixture, and restrains the DDT. Furthermore, a novel dimensionless criterion and a characteristic parameterTurcare proposed, quantitatively analyzing the dominate mechanism in flame propagation and the initial stage of DDT as inert jet is introduced.
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典型可燃混合物中爆炸不稳定性对接近极限的传播模式的影响
影响因子：
7.4
作者：
Zhang Bo;Liu Hong;Li Yuanchang
通讯作者：
Li Yuanchang
可燃气体混合物爆炸极限的理论预测模型和实验研究
影响因子：
7.4
作者：
Zhang Bo;Liu Hong
通讯作者：
Liu Hong
影响因子：
4.4
作者：
Bo Zhang
通讯作者：
Bo Zhang
影响因子：
7.4
作者：
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通讯作者：
J. Chambers;K. Ahmed
DOI：
10.2514/6.2011-587
发表时间：
2011-01
期刊：
--
影响因子：
--
作者：
Benjamin Knox;D. Forliti;C. A. Stevens;J. Hoke;F. Schauer
通讯作者：
Benjamin Knox;D. Forliti;C. A. Stevens;J. Hoke;F. Schauer