内管扰动对氢气爆轰波传播影响的实验研究

Experimental Study on the Influence of Inner Tube Disturbance on H_(2) Detonation Propagation

为研究内管扰动对氢气爆轰波传播过程的影响,在光滑管和多尺寸环形管道中完成爆轰实验,以烟膜记录外管内壁和内管内壁胞格结构。结果显示,横波衰减导致爆轰波的胞格结构发生明显改变。当初始压力P_(0)从15 k Pa降到9 k Pa,爆轰波传播距离变短,从点火端到胞格发生明显变化位置的距离(即L_(λC))减小,光滑管中,L_(λC)^(0)从3671.39 mm减少到3484 mm,环形管中,L_(λC)^(20)(d_(1)=20 mm)从3557.59 mm减少到3000 mm,L_(λC)^(40)(d_(2)=40 mm)从3660.33 mm减少到3420.7 mm。同时可见,相对于光滑管道,同一P_(0)时,环形管道中的L_(λC)减小,说明插入内管后,边界层效应对氢气爆轰波传播产生的影响增大。文中考虑了l_(λC)/d与初始压力P_(0)的关系(l_(λC)表示距点火3000 mm处到内管内壁烟膜上胞格发生明显变化位置的距离),结果显示,当P_(0)增加时,l_(λC)^(60)/d的值变化缓慢,即对于较大的环形管道,爆轰波的传播过程受P_(0)的影响不大,主要受边界层效应的影响。

In order to study the influence of inner tube disturbance on H_(2)detonation propagation,smaller tubes with d_(1)=20 mm,d_(2)=40 mm,and d_(3)=60 mm were inserted into the smooth tube with inner diameter D=80 mm to form annular tubes.In the experiments,the smoked foils were set on the inner wall of the outer tubes and the inner wall of the inner tubes to observe the evolution of the detonation cellular structure under different initial conditions.Clearly,the results fold that during the propagation of the detonation,the attenuation of the transverse wave causes a significant change in the detonation cellular structure.Then,L_(λC)refers to the length from the ignition end to the location where the cellular structure changes significantly.In smooth tube,when the initial pressure is reduced from 15 kPa to 9 kPa,the detonation propagation distance becomes shorter,and L_(λC)^(0)is also reduced from 3671.39 mm to 3484 mm.In the annular tubes,when the initial pressure is reduced from 15 kPa to 9 kPa,L_(λC)^(20)is reduced from 3557.59 mm to 3000 mm,L_(λC)^(40)is reduced from 3660.33mm to 3420.7 mm.Obviously,the changing trend is the same as that in the smooth tube.However,the L_(λC)in the annular tubes is shorter than that in the smooth tube under the same initial pressure,which due to the increase of the boundary layer effect.Furthermore,for an annular tube with alarger inner tube diameter(d_(3)=60 mm),as P_(0)increases from 6 kPa to 15 kPa,the value of l_(λC)^(60)/d(l_(λC)refers to the length from the ignition 3000 mm to the position where the cellular structure on the inner wall of the inner tube changes significantly)changes slowly.In other words,the detonation propagation is not greatly affected by the initial pressure,mainly by the boundary layer effect.