A 2D fluid model was employed to simulate the influence of dielectric on the propagation of atmospheric pressure helium plasma jet based on coplanar dielectric barrier discharge（DBD）.The spatio-temporal distribution...A 2D fluid model was employed to simulate the influence of dielectric on the propagation of atmospheric pressure helium plasma jet based on coplanar dielectric barrier discharge（DBD）.The spatio-temporal distributions of electron density,ionization rate,electrical field,spatial charge and the spatial structure were obtained for different dielectric tubes that limit the helium flow.The results show that the change of the relative permittivity of the dielectric tube where the plasma jet travels inside has no influence on the formation of DBD itself,but has great impact on the jet propagation.The velocity of the plasma jet changes drastically when the jet passes from a tube of higher permittivity to one of lower permittivity,resulting in an increase in jet length,ionization rate and electric field,as well as a change in the distribution of space charges and discharge states.The radius of the dielectric tube has a great influence on the ring-shaped or solid bullet structure.These results can well explain the behavior of the plasma jet from the dielectric tube into the ambient air and the hollow bullet in experiments.展开更多
基于简化标记和单元(Simplified marker and cell,SMAC)方法,发展一种在任意曲线坐标系中求解三维非定常不可压湍流Reynolds时均方程的隐式数值方法。控制方程包括以逆变速度为变量的动量方程、压力Poisson方程和k-ε湍流模型方程,控制...基于简化标记和单元(Simplified marker and cell,SMAC)方法,发展一种在任意曲线坐标系中求解三维非定常不可压湍流Reynolds时均方程的隐式数值方法。控制方程包括以逆变速度为变量的动量方程、压力Poisson方程和k-ε湍流模型方程,控制方程的离散在三维标记和单元(Marker and cell,MAC)交错网格系统中进行。为提高方程数值计算的稳定性,动量方程、k方程和ε方程对流项离散均采用Chakravarthy-Osher总变差衰减(Total variation diminishing,TVD)格式。动量方程、k方程和ε方程离散后的代数方程组采用循环三对角阵算法(Cyclic tridiagonal matrix algorithm,CTDMA)方法进行求解,Poisson方程离散后的代数方程组采用Tschebyscheff超线性松弛(successive linear over relaxation,SLOR)方法交替方向迭代求解。用该方法自编程序对简化后的射流放水阀内非定常流场进行数值模拟,计算结果和试验结果吻合。展开更多
文摘A 2D fluid model was employed to simulate the influence of dielectric on the propagation of atmospheric pressure helium plasma jet based on coplanar dielectric barrier discharge（DBD）.The spatio-temporal distributions of electron density,ionization rate,electrical field,spatial charge and the spatial structure were obtained for different dielectric tubes that limit the helium flow.The results show that the change of the relative permittivity of the dielectric tube where the plasma jet travels inside has no influence on the formation of DBD itself,but has great impact on the jet propagation.The velocity of the plasma jet changes drastically when the jet passes from a tube of higher permittivity to one of lower permittivity,resulting in an increase in jet length,ionization rate and electric field,as well as a change in the distribution of space charges and discharge states.The radius of the dielectric tube has a great influence on the ring-shaped or solid bullet structure.These results can well explain the behavior of the plasma jet from the dielectric tube into the ambient air and the hollow bullet in experiments.
文摘基于简化标记和单元(Simplified marker and cell,SMAC)方法,发展一种在任意曲线坐标系中求解三维非定常不可压湍流Reynolds时均方程的隐式数值方法。控制方程包括以逆变速度为变量的动量方程、压力Poisson方程和k-ε湍流模型方程,控制方程的离散在三维标记和单元(Marker and cell,MAC)交错网格系统中进行。为提高方程数值计算的稳定性,动量方程、k方程和ε方程对流项离散均采用Chakravarthy-Osher总变差衰减(Total variation diminishing,TVD)格式。动量方程、k方程和ε方程离散后的代数方程组采用循环三对角阵算法(Cyclic tridiagonal matrix algorithm,CTDMA)方法进行求解,Poisson方程离散后的代数方程组采用Tschebyscheff超线性松弛(successive linear over relaxation,SLOR)方法交替方向迭代求解。用该方法自编程序对简化后的射流放水阀内非定常流场进行数值模拟,计算结果和试验结果吻合。
