DDT in a smooth tube filled with a hydrogen–oxygen mixture
DDT in a smooth tube filled with a hydrogen–oxygen mixture
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DOI：
10.1007/s00193-005-0265-6
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发表时间：
2005-09
期刊：
影响因子：
2.2
通讯作者：
Mike Kuznetsov;V. Alekseev;I. Matsukov;S. Dorofeev
中科院分区：
文献类型：
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作者：
Mike Kuznetsov;V. Alekseev;I. Matsukov;S. Dorofeev
本文介绍了爆轰波在光滑管内的实验研究结果，爆轰波的爆轰元尺寸比管道直径小1 ~ 3个数量级。在试验中使用化学计量的氢-氧混合物，初始压力为0.2至8巴。研究了DDT的起动距离对初始压力的依赖性。这种依赖关系被发现是接近反比。这表明火焰前的流动导致湍流边界层的形成。这个边界层控制着流动中湍流运动的尺度。本文提出了一个简单的模型来估算沿管沿着火焰位置处湍流脉动的最大尺度（边界层厚度）。在所有试验中，爆轰起始位置处的湍流运动的最大尺度比爆轰单元宽度λ大1个数量级。当湍流脉动的最大尺度增加到约10 λ时，在火焰加速过程中，爆震波的发生被触发。估算湍流运动最大尺度δ的模型和相关系数δ = 10λ，为估算内径D> 20λ的管道中DDT的起动距离提供了依据。
Results of experimental study on DDT in a smooth tube filled with sensitive mixtures having detonation cell size from 1 to 3 orders of magnitude smaller than the tube diameter are presented. Stoichiometric hydrogen–oxygen mixtures were used in the tests with initial pressure ranging from 0.2 to 8 bar. A dependence of the run-up distance to DDT on the initial pressure is studied. This dependence is found to be close to the inverse proportionality. It is suggested that the flow ahead of the flame results in formation of the turbulent boundary layer. This boundary layer controls the scale of turbulent motions in the flow. A simple model to estimate the maximum scale of the turbulent pulsations (boundary layer thickness) at flame positions along the tube is presented. The largest scale of the turbulent motions at the location of the onset of detonation is shown to be 1 order of magnitude greater than the detonation cell widths, λ, in all the tests. It is suggested that the onset of detonation is triggered during flame acceleration as soon as the maximum scale of the turbulent pulsations increases up to about 10 λ. The model to estimate the maximum size of turbulent motions, δ, and the correlation δ≈ 10λ, give a basis for estimations of the run-up distances to DDT in tubes with internal diameterD> 20λ.