氘、氦及其混合物状态方程第一原理研究

利用量子分子动力学方法对氘、氦及其混合物的状态方程进行了研究. 计算了氦在密度0.32-5 g/cm³, 温度1000-50000 K范围内的状态方程, 并与化学模型的结果进行了比较; 同时计算了冲击Hugoniot曲线, 与气炮实验的结果符合得很好. 通过计算对分布函数及态密度, 探讨了氦在高温高压下发生金属-绝缘体转变的机理. 计算了氘在密度0.19-0.84 g/cm³, 温度20-50000 K范围内的状态方程; 并计算了理论Hugoniot状态, 由于没有考虑原子的零点运动, 在低温区, 理论结果比实验值小. 对氘氦混合物的状态方程进行了研究, 计算了温度和密度区间为100-50000 K, 0.19-0.84 g/cm³, 不同混合度下的293个状态点的状态方程. 对线性混合近似进行了考查, 结果表明线性混合近似是一个粗略的近似.     

ICF靶丸内燃料的气液两相组分组成分析

 在质量守恒的基础上,运用拉乌尔定律和道尔顿分压定律,对以摩尔分数比为3∶3∶4比例充入到ICF靶丸内的氘气、氚气和氘化氚三元系的热核燃料,在工作温度为22,24,26,28和30 K下处于相平衡时气液两相的组分组成进行了分析讨论。结果显示:工作温度为22 K时,随着充气压强从1 MPa增大到5 MPa,液层中氘气的摩尔分数从0.251增大到0.290,氚气的摩尔分数从0.350减小到0.310;气泡中氘气的摩尔分数从0.322增大到0.365,氚气的摩尔分数从0.278减小到0.241。充气压强为5 MPa时,随着工作温度从22 K提高到30 K,液层中氘气摩尔分数从0.290减小到0.261,氚气的摩尔分数从0.309增大到0.341;气泡中氘气的摩尔分数从0.365减小到0.302,氚气的摩尔分数从0.241增大到0.298。     

压缩氘氚球的热核燃烧特性研究

本文利用LARED-S程序模拟了等密度和等压力条件下压缩氘氚球的热核反应燃烧过程.对于等密度模型,模拟了两个具体算例,与国外计算结果进行了比较,验证了程序的可靠性.对于等压力模型,利用数值模拟给出了热核反应燃烧与压缩氘氚球初始状态之间的关系曲线,分析发现,氘氚装量、压力和主燃料密度的增加有利于提高热核反应放能和燃耗,中心热斑的温度和面密度分别达到70—80 MK和3—4 kg·m^-2时热核反应才有显著的放能,提高主燃料密度,可以适当放宽对中心热斑的点火要求.最后对实际点火靶进行了数值模拟并且与等压力模拟计算结果进行了比较分析. 关键词： 压缩氘氚球 等密度模型 等压力模型 热核反应聚变     

压缩氘氚球的热核燃烧特性研究

本文利用LARED-S程序模拟了等密度和等压力条件下压缩氘氚球的热核反应燃烧过程.对于等密度模型,模拟了两个具体算例,与国外计算结果进行了比较,验证了程序的可靠性.对于等压力模型,利用数值模拟给出了热核反应燃烧与压缩氘氚球初始状态之间的关系曲线,分析发现,氘氚装量、压力和主燃料密度的增加有利于提高热核反应放能和燃耗,中心热斑的温度和面密度分别达到70—80 MK和3—4 kg·m^-2时热核反应才有显著的放能,提高主燃料密度,可以适当放宽对中心热斑的点火要求.最后对实际点火靶进行了数值模拟并且与等压力模拟计算结果进行了比较分析.     

氘平面冷冻靶制备技术研究

在激光惯性约束聚变（ICF）实验研究中,需要研究一些原子／分子（如氩、氢、氘、氚等）在低温冷冻状态下与强冲击波的相互作用,获得相关的状态方程实验数据。为此,需要创造一个稳定的低温环境,将这些在常温下为气态的原子／分子冷冻成固态或液态。美国已经建立了平面冷冻靶制备实验装置,并在OMEGA实验装置上利用液氘平面低温冷冻靶获得了其状态方程实验数据。     

氢同位素交换催化剂制备及性能

聚变反应堆或聚变裂变混合堆氚工厂中,氘氚燃料回收和含氚废水、废气处理过程中,涉及液态水、汽态水和甲烷与氢气间的同位素交换反应,催化剂是实现这些反应的关键。     

高温高压下液态铁的状态方程

基于高温高压下面心立方(FCC)铁的状态方程和熔化温度实验数据,建立了热力学模型计算FCC铁、固-液混合相、液态铁在高温高压下的状态方程.在相同密度和温度下,计算的FCC铁、固-液混合铁、液态铁的压强与实验测量结果较为一致,且计算结果与实验结果平均偏差分别为-1.61 GPa、1.05 GPa、-0.05 GPa.在0～100 GPa压强范围内,当铁完全发生熔化时,随着压强的增大其密度变化由-7.5%下降至2.7%.     

托卡马克氘氚聚变堆中氚的二倍频ICRF加热物理分析

本文从准线性理论出发，导出了ＩＣＲＦ二倍频加热时对磁面平均的吸收功率密度的近似解析表达式，并指出了这一近似的适用范围。采用冷等离子体近似计算波的色散关系，利用ＥＰＰＡＣ程序求解二维时间相关Ｆｏｋｋｅｒ－Ｐｌａｎｃｋ方程，分析了氚的二倍频加热。对于典型的氘氚聚变反应堆参数，计算了等离子体各组分温度随时间的变化及氚的分布函数随时间的演化，并分析了氚的非麦氏分布及相关的氘氚聚变反应率。结果表明，对于反应堆规模的等离子体来说，ＩＣＲＦ加热只在温度不太高时才导致明显的非麦氏分布及氘氚聚变反应率提高；在等离子体温度提高到约１０ｋｅＶ后，反应率不再有明显的提高     

冷冻靶校准误差和烧蚀层粗糙度对氘氚层均匀性的影响

 理论分析了氘氚层外表面的温差与其粗糙度间的关系;以法国兆焦激光装置LMJ为原型,利用计算流体力学程序Fluent,分别模拟了靶丸轴向偏离黑腔中心不同尺度和烧蚀层存在不同大小的非均匀厚度对氘氚层温度分布的影响,求得了这两种误差引起氘氚层厚度的非均匀度。结果表明：为了满足点火靶的要求,靶丸轴向偏离腔体中心的尺度须在8.5 μm内,烧蚀层轴向粗糙度则应控制在0.72 μm内。     

氘在碳钨共沉积层中的滞留行为研究

运用射频磁控溅射方法, 在氘氩混合气氛中制备了含氘碳钨共沉积薄膜. 利用离子束分析方法[卢瑟福背散射(RBS)和弹性反冲(ERD)]对薄膜样品的厚度、成分、 氘含量等进行了分析; 利用拉曼光谱和扫描电子显微镜(SEM), 分别分析了薄膜的结构和表面形态. 离子束分析发现, 氘原子更易被碳原子俘获位俘获, 并且氘含量会随着沉积温度的升高而降低; 其他镀膜条件固定的情况下, 不同混合气体压强下薄膜样品中的氘浓度在5.0 Pa处有一个峰值; 拉曼光谱分析显示, 沉积温度从室温升高到725 K时, 碳钨共沉积层中的类石墨化成分增加, 同时, 非晶化的程度也加剧; 扫描电子显微镜图像表明, 随着温度的升高薄膜表面被腐蚀的痕迹消失, 但是由于应力的改变表面出现了多处的凸起. 关键词： 氘滞留 碳钨共沉积 射频磁控溅射     

Generation of the line radiation of argon added to DT gas in Iskra-5 experiments

The first experiments measuring the density of a compressed deuterium and tritium mixture in microtargets of indirect irradiation (x-ray targets) were performed at the Iskra-5 facility. The density was determined according to the broadening of the lines of hydrogen-and helium-like argon added to the DT gas as a diagnostics material. A series of three experiments was performed with x-ray targets in which the central capsule filled with a DT + Ar mixture over a range of shell thicknesses. In two of the experiments, argon emission spectra were recorded and the density of the compressed gas was determined. For a microtarget approximately 280 μm in diameter with a wall approximately 7 μm thick, an analysis of the experimental results yielded an estimated density in the compressed gas of ∼1 g/cm³. Gas-dynamic calculations using the SNDA (spectral nonequilibrium diffusion with absorption) program show that argon emission takes place just after reaching maximum temperature, but much sooner than maximum compression. The results of a calculation for an experiment with low relative Ar concentration are in overall agreement with the experimental data. Additional investigations are needed to interpret experiments at a relatively high concentration. Zh. éksp. Teor. Fiz. 114, 837–848 (September 1998)     

混合物状态方程的计算

多介质流体动力学过程的数值模拟往往涉及混合物状态方程的计算. 做图法和Newton 法是混合物状态方程计算常采用的方法, 前者虽直观精度却差, 后者计算效率高却只具有局部收敛性, 当解与其初始猜测值相差较远时Newton法不一定能够获得收敛解. 为此, 本文给出一种具有大范围收敛性的嵌入算法(imbedding method)求解混合物状态方程, 其基本思想是通过引入嵌入参数, 将待解的混合物状态方程和易解的混合物状态方程线性组合, 构成嵌入方程组, 当嵌入参数从0连续地变化到1 时, 嵌入方程组的解由易解的混合物状态方程的解连续地变化为待解的混合物状态方程的解. 嵌入方程组可由Newton法迭代求解, 也可转化为以嵌入参数为自变量的常微分方程组, 从而易于由成熟的计算方法如梯形法等进行求解. 进一步利用热力学基本关系, Maxwell形式的微分方程描述了压力和温度随嵌入参数的演化速率与应变速率和组分质量分数演化速率的关系. 对铅锡混合物热力学量的计算表明了本文算法的有效性.     

Prediction of gas tungsten arc welding properties in mixtures ofargon and hydrogen

A theory of gas tungsten arc welding (GTAW) arcs that treats the tungsten electrode, the arc, and the workpiece as a unified system has been applied to make predictions in two dimensions of the temperature distributions in the arc, the tungsten cathode, and the workpiece, for any given arc current and gas mixture. Predictions of arc temperatures, radii, and voltages are compared for argon and mixtures of argon and hydrogen. It is found that arcs in gas mixtures containing hydrogen are more constricted and have a higher maximum temperature and arc voltage than arcs in pure argon. The addition of hydrogen also significantly increases the volume of molten material in the weld pool due to the higher thermal conductivity of argon-hydrogen mixtures at temperatures at which molecules of hydrogen dissociate. Predictions are also compared for workpieces of steel and aluminum. The volume of molten material is very much less for aluminum, despite its lower melting point, because of the higher thermal conductivity of aluminum. Predicted arc voltages as a function of current for a mixture of 10% hydrogen in argon are in good agreement with experimental results     

非理想性参数在0.9～2.1区的氩等离子体物态方程研究

采用平面冲击压缩方法产生密度和温度都均匀的氩等离子体,根据辐射高温计记录和飞片速度的测定,通过阻抗匹配方法确定了氩等离子体的Hugoniot物态方程,等离子体温度在1.5 eV～2.6 eV范围,压力在0.2～0.8 GPa之间.计算表明,Saha-Debye-Hückel模型不适用于描述该密度区域的氩等离子体.本文采用Gryaznov模型的计算结果,测量值和理论计算结果符合较好.     

混合物物态方程的计算

 在采用体积相加原理计算混合物物态方程的基础上,建立了一种物理模型确定混合物温度。根据混合物中各组分温度和压强平衡条件,采用压强-密度迭代方法计算给出混合物物态方程,编制了两种组分的混合物物态方程计算程序。为检验建立的温度模型的合理性及程序的有效性,分析了不同密度、温度状态的氢（H2）和钨（W）组成的混合物状态参量,计算了以下情形及其组合情形的混合物物态方程：H₂和W以不同质量比混合;质量比固定,单组分状态不同;温度区间和密度区间不同。研究表明:实际应用中在建立的混合物温度模型基础上确定的混合物物态方程是合理的。     

Ar+ and Xe+ velocities near the presheath-sheath boundary in an Ar/Xe discharge

The velocities of Ar+ and Xe+ ions near the presheath-sheath boundary in an Ar/Xe discharge are studied by particle-in-cell Monte Carlo simulation. For a pure argon discharge the argon ion has almost the same velocity profile as it does in the mixture of argon and xenon. Similarly, for a xenon discharge the xenon ion has almost the same velocity profile as it does in the mixture of argon and xenon. The ion speed at the sheath-presheath boundary is the same for an ion in a pure argon or xenon discharge and for the same ion in a mixture of argon and xenon. We conclude that, in our simulation, each ion reaches its own Bohm speed at the presheath-sheath interface.     

小功率等离子体射流的流特性

采用焓探针对小功率(5kW)热喷涂等离子体射流的焓、温度和速度进行了测量和计算。研究了气体成分、流量、电弧电压和电流对等离子流体的焓、温度和速度分布的影响。结果表明,对于单一氩气等离子体,当使用新喷嘴时,增大氩气流量能够使喷嘴内部电弧弧根向出口方向移动,从而增加等离子体射流的焓、温度和速度。对于Ar-N2等离子体,增加气体中氮气的含量,会提高等离子电弧电压,在同样的输入功率下,改变等离子电流和电压对等离子体的焓、温度和速度影响较小。对于Ar-N2等离子体,增加氢气含量会明显地提高等离子射流的速度和热传递。     

Universal cubic equation of state and contact values of the radial distribution functions for multi-component additive hard-sphere mixtures

A universal cubic equation of state (UC EOS) is proposed based on a modification of the virial Percus-Yevick (PY) integral equation EOS for hard-sphere fluid. The UC EOS is extended to multi-component hard-sphere mixtures based on a modification of Lebowitz solution of PY equation for hard-sphere mixtures. And expressions of the radial distribution functions at contact (RDFC) are improved with the form as simple as the original one. The numerical results for the compressibility factor and RDFC are in good agreement with the simulation results. The average errors of the compressibility factor relative to MC data are 3.40%, 1.84% and 0.92% for CP3P, BMCSL equations and UC EOS, respectively. The UC EOS is a unique cubic one with satisfactory precision among many EOSs in the literature both for pure and mixture fluids of hard spheres.     

一种新的对比态混合物状态方程的建立

1引言在混合替代工质的研究中，要分析其热力学性质和循环性能，必须有能够准确描述混合制冷剂性质的状态方程。目前计算采用的各种混合状态方程都必需有混合物各组分间的二元交互作用系数Kij。Kij的值一般需要由回归二元混合工质的PVTx实验数据或相平衡数据而得到。实际的混合工质替代研究中，常常没有或缺少混合物的实验数据。对于二元混合物而言，其热力性质应与组成这种混合物的两种纯质的性质密切相关，有可能以纯质的物性来表达混合物的性能，而大多数纯质制冷剂都有用实验数据回归的精度很高的专用状态方程和蒸气压方程。所以，如…     

Influence of temperature on the ionization coefficient and ignition voltage of the Townsend discharge in an argon–mercury vapor mixture

The kinetics of main types of charged and excited particles present in a low-current discharge in an argon–mercury vapor mixture used in gas-discharge illuminating lamps has been investigated in a wide interval of the reduced electric field strength and temperature. Mechanisms behind the production and loss of ions and metastable atoms have been discovered, and the temperature dependences of their contributions to maintaining their balance have been determined. It has been shown that, when the discharge is initiated in the lamp and the mercury content in the mixture is low, the ionization coefficient exceeds that in pure argon, which is almost exclusively due to the Penning reaction. The influence of this reaction grows with a reduction of the electric field strength in the interelectrode gap. The dependences of the discharge ignition voltage on the interelectrode gap (Paschen curves) for different temperatures of the mixture have been calculated, and the nonmonotonicity of the temperature dependence of the ignition voltage has been explained.