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 An investigation of toroidal shock wave motion in a cylindrical shock tube is described in this paper. Numerical simulations were carried out by using dispersion controlled dissipation scheme (DCD scheme) and validated with experimental data. From the numerical results, the toroidal shock wave diffraction, focusing and reflection were discussed in detail. It was found out that the key factor of cylindrical shock focusing is the shock acceleration when diffracting shock waves propagate toward the axis of symmetry.... An investigation of toroidal shock wave motion in a cylindrical shock tube is described in this paper. Numerical simulations were carried out by using dispersion controlled dissipation scheme (DCD scheme) and validated with experimental data. From the numerical results, the toroidal shock wave diffraction, focusing and reflection were discussed in detail. It was found out that the key factor of cylindrical shock focusing is the shock acceleration when diffracting shock waves propagate toward the axis of symmetry. Mach numbers of incident toroidal shock waves play an important role in shock wave diffraction and focusing. The toroidal shock waves focus at certain point on the axis of symmetry while usual cylindrical shock waves focus on the entire the axis of symmetry, therefore, the focusing effect resulting from the two cases of focusing points are different essentially.  应用频散可控耗散格式对环形激波在圆柱形激波管内绕射、反射和聚焦的问题进行了数值模拟研究.研究结果表明环形激波形成强烈聚焦的关键因素是环形激波在圆柱形管道中向对称轴运动时,绕射激波就不断加速而不作通常情况下的衰减;不同马赫数的环形激波绕射也产生不同马赫数及形状的准柱形激波,导致聚焦效果和位置的差异;另外,环形激波聚焦于一个点而圆柱形激波聚焦于一条线,两者有本质不同.  In this paper, the chemically reacting flowfield of detonation reflection over wedges was simulated numerically. The dispersioncontrolled dissipative scheme (DCD) was adopted to solve twodimensional Euler equations implemented with detailed chemical reaction kinetics of hydrogenoxygenargon mixture. The fractional step method was applied to treat the stiff problem arising from computation of chemical reaction flow. The wedge angle, initial pressure and composition of the mixture were taken into consideration... In this paper, the chemically reacting flowfield of detonation reflection over wedges was simulated numerically. The dispersioncontrolled dissipative scheme (DCD) was adopted to solve twodimensional Euler equations implemented with detailed chemical reaction kinetics of hydrogenoxygenargon mixture. The fractional step method was applied to treat the stiff problem arising from computation of chemical reaction flow. The wedge angle, initial pressure and composition of the mixture were taken into consideration respectively to evaluate their effect on the angle X of triplepoint trajectory of detonation reflection over wedges. From the numerical results it is observed that the critical wedge angle α_(crit) for the transition from Mach reflection to regular reflection of detonation wave is close to the experimental data or CCW theoretical result. The numerical results also show that the angle X of triplepoint trajectory is mainly depend on wedge angle a and is not sensitive to variation of the initial pressure Po.  应用基元反应模型和频散可控耗散格式(DCD)对氢氧爆轰波在楔面反射进行了数值模拟,计算中氢氧混合物的化学反应采用了8种组分20个反应方程式,在处理化学反应引起的刚性问题时采用了时间算子分裂的方法,模拟了爆轰波在楔面反射由马赫反射向规则反射转变的过程,得到了反射转变临界角,同时考虑了初始压力和组分的影响,并和实验及理论分析结果进行了比较,结果是令人满意的。  The chemically reacting flowfield of a detonation wave in a bend is simulated by CFD method. The dispersioncontrolled dissipative scheme(DCD) is adopted to solve twodimensional Euler equations implemented with detailed chemical reaction kinetics of hydrogenoxygenargon mixture. The fractional step method is applied to treat the stiff problem arising from computation of chemical reaction flow. From the numerical results it is observed that as the curvature of the bend changes,different detonation phenomena... The chemically reacting flowfield of a detonation wave in a bend is simulated by CFD method. The dispersioncontrolled dissipative scheme(DCD) is adopted to solve twodimensional Euler equations implemented with detailed chemical reaction kinetics of hydrogenoxygenargon mixture. The fractional step method is applied to treat the stiff problem arising from computation of chemical reaction flow. From the numerical results it is observed that as the curvature of the bend changes,different detonation phenomena occurred along the wall of the bended pipe.If detonation wave propagating through bend with little curvature,the affection of the expansion wave is then stronger to induce the decouple process of the reaction zone and the leading shock.Resetup of detonation can be completed when the overdriven detonation from another wall reignites the gas mixture in the decoupled zone,and then high overpressure impacts on the bend wall.  应用基元反应模型和频散可控耗散格式(DCD)对氢氧爆轰波在弯管内的传播过程进行了数值模拟.计算中氢氧混合物化学反应采用了8种组分20个反应方程式.在处理化学反应引起的刚性问题时采用了时间算子分裂的方法.计算结果表明,在弯管小曲率半径壁面附近,由于膨胀稀疏作用,爆轰波强度减弱,在局部出现前导激波与放热反应区的解藕以及二次起爆现象;在弯管大曲率半径壁面上爆轰波在马赫反射和正规反射之间相互转变,使爆轰波加强.弯管内的爆轰现象与弯管曲率半径有关.   << 更多相关文摘 
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