圆柱谐振腔式MPCVD装置中氢、氩微波等离子体分布规律的数值模拟

在使用简化的等离子体放电模型的基础上,模拟了圆柱谐振腔式微波等离子体沉积室中,不同金刚石膜生长条件下微波等离子体的分布状态。在模拟中,针对纳米金刚石的生长环境,就纯氩气反应气体中,不同的输入功率、不同气体压力条件下,沉积室中形成的等离子体分布的变化规律进行了模拟,将其与一般氢气气氛下的相应模拟结果相对比。模拟所获得的结果,对微波等离子体方法沉积金刚石膜的操作环境的优化,有着一定的指导意义。     

一种改进的气动弹性时域推进方法

针对气动弹性控制方程,结构项采用标准龙格库塔方法推进,广义气动力项采用时间上的插值技术,发展了一种在每一时间步内只用计算一次非定常气动力的近似四阶龙格库塔推进方法。通过计算非线性Bernoulli方程和某一超音速翼面的气动弹性响应,证明该方法的时间准确度远高于采用气动力冻结技术的四阶龙格库塔方法。其准确度与标准龙格库塔方法相差不大,而其调用非定常气动力求解器的次数仅为其四分之一,大大提高了气动弹性数值模拟的效率。对于一般的气动弹性响应而言,该时间推进方法只用保证每个周期内的时间步在20～30个左右就能满足较高的准确度要求。     

Simulating Retention in Gas–Liquid Chromatography: Benzene, Toluene, and Xylene Solutes

Accurate predictions of retention times, retention indices, and partition constants are a long sought-after goal for theoretical studies in chromatography. Although advances in computational chemistry have improved our understanding of molecular interactions, little attention has been focused on chromatography, let alone calculations of retention properties. Configurational-bias Monte Carlo simulations in the isobaric–isothermal Gibbs ensemble were used to investigate the partitioning of benzene, toluene, and the three xylene isomers between a squalane liquid phase and a helium vapor phase. The united-atom representation of the TraPPE (transferable potentials for phase equilibria) force field was used for all solutes and squalane. The Gibbs free energies of transfer and Kovats retention indices of the solutes were calculated directly from the partition constants (which were averaged over several independent simulations). While the calculated Kovats indices of benzene and toluene at T=403 K are significantly higher than their experimental counterparts, much better agreement is found for the xylene isomers at T=365 K.     

Numerical simulation for rheological characteristics of alternating distribution of soft and hard rock layers

The difficulty of selecting appropriate rheological model and parameters for the alternating distribution of soft and hard rock layers was often encountered due to the unhomogeneity, discontinuity and anisotropy of rock mass. The Burgers and generalized Kelvin models were applied to the soft and hard rock respectively and the rheological parameters were obtained based on the method of optimum separation. By using the simulated code FLAC^3D, the stability of surrounding rocks of a certain underground plant was analyzed. The effect of surface load and weakening the parameters intensity of argillaceous and bioclastic interlayers between soft and hard rock on rheological behavior of layer composite rock mass was investigated. The results indicate that the rheological characteristics of soft and hard rock layer in composite rock mass can be described well with above two rheological models.     

深圳水库排洪河综合整治工程设计

以深圳水库排洪河水环境综合整治工程为例,探讨在城市河道综合整治设计中如何体现人与大自然和谐相处的理念,尊重大自然,满足河道防洪安全,恢复河流活跃、多样的生态系统,美化周边环境,创造多样性功能的河流空间。     

InfluenCe of Downstream Flow on Conduction Phase of Coaxial Plasma Opening Switch

Plasma behaviour and the scaling relations in a coaxial plasma opening switch （POS） using hydrogen plasma are studied self-consistently based on the two-dimensional magnetohydrodynamic （MHD） equations in conjunction with the generalized Ohm＇s law. The vacuum region on the right of POS is included in the model and the influence of downstream flow on the conduction characteristics is discussed. It is found that with the penetration of magnetic field, the pure hydrogen plasma is pushed downstream significantly; and POS still conducts current after the magnetic field arrives at the load edge of POS, which is different from the previous experimental results in a multispecies POS. It is because that the noticeable downstream plasma in the pure hydrogen POS may continue to conduct the current, while in the multispecies POS, the downstream plasma is unimportant so that the conduction phase ends soon after the magnetic field reaches the load edge. The scaling relation obtained from the simulations including the downstream region is consistent with the experimental results.     

WT615增压CNG电喷发动机燃烧特性数值分析

以WT615 CNG发动机为模拟研究对象,采用KIVA-3V软件建立了多维软件计算模型,并验证了模型的准确性。在此基础上研究了主要结构参数——燃烧室形状对燃烧特性和整机性能的影响。研究表明,直口形燃烧室的动力性、经济性能最好,更加适用于该天然气发动机,但排放性能有待提高;缩口形燃烧室的整机性能次之,碗形燃烧室的动力性和经济性则较差,后燃现象严重,不适用于天然气发动机。     

铜合金六通接头体热挤压刚粘塑性有限元模拟

本文利用刚粘塑性有限元法,对六通接头的热挤压成形进行了热力耦合的数值模拟,获得了热挤压成形的载荷和行程的关系曲线,应力、应变和温度的分布信息.模拟结果表明,在工件挤压温度为730℃和模具预热温度为400℃时,挤压速度范围是70mm/s～80mm/s.这一模拟结果对后期的工艺制定和模具设计提供了参考.     

论泾河东庄水库灰岩坝址渗漏问题

通过对泾河东庄水库灰岩坝址工程地质钻探成果特别是钻孔压水试验及水文地质成果包括区域水质、水位、水温等不连通性的分析研究,并结合流量测定三维渗漏数值模拟分析,对坝区渗漏问题进行分析和论证,进一步证明在泾河下游东庄灰岩段建坝是可行的,不会发生严重渗漏,为项目的设计、审查、决策方面参考,以促进工程前期工作的进展。     

微扰理论总结

电磁兼容数值仿真需要建立电子设备的仿真模型,但是实际电子设备模型比较复杂,包括有大量的微小结构,如各种安装凸台、凹槽等.如果按照实际的模型建立仿真模型会耗费大量的人力物力.同时复杂的模型会使计算量急剧的增加,过于复杂的模型也会导致网格的畸变,导致错误的仿真结果.因此在电磁兼容仿真建模过程中,必须对电子设备的仿真模型加以简化或等效处理.本文基于国内外对微扰问题研究,给出电子设备建模过程中模型简化的基本原理,即微扰理论.并对以后的研究提出相关的思路和方法.