Investigation of impurity transport using supersonic molecular beam injected neon in HL-2A ECRH plasma

In this paper, we describe the behavior of impurity transport in the HL-2A electron cyclotron resonance heating （ECRH） L-mode plasma. The neon as a trace impurity is injected by the supersonic molecular beam injection （SMBI） technique, which is used for the first time to study the impurity transport in HL-2A. The progression of neon ions is monitored by the soft X-ray camera and bolometer arrays with good temporal and spatial resolutions. The convection and diffusion process of the neon ions are investigated with the one-dimensional impurity transport code STRAHL. The results show that the diffusion coefficient D of neon ions is a factor of four larger than the neoclassical value in the central region. The value of D is larger in the outer region of the plasma （ρ 〉 0.6） than in the central region of the plasma （ρ 〈 0.6）. The convective velocity directs inwards with a value of ～-1.0 m/s in the Ohmic discharge, but it reverses to direct outwards with a value of ～ 8.0 m/s in the outer region of the plasma when ECRH is applied. The result indicates that the impurity transport is strongly enhanced with ECRH.     

泵站水泵进水池内防涡装置有效性的数值验证

本文提出了一种消除泵站水泵吸水管内旋涡和流动分离的圆锥形防涡装置。为了验证该装置的有效性,建立了泵站水泵进水池和吸水管内三维湍流流场的数学模型,用分区网格构造了泵站水泵进水池和吸水管的贴体计算网格,采用有限体积方法,计算了无圆锥形防涡装置和有圆锥形防涡装置时,水泵进水池和吸水管内三维湍流流场,结果证明该圆锥形防涡装置能有效消除水泵吸水管内旋涡和流动分离。     

EAST托卡马克杂质输运蒙特卡洛模拟

介绍DIVIMP程序的基本思想和采用的物理模型,研究EAST托卡马克欧姆放电条件下碳杂质的产生与输运.模拟结果与实验测量具有较好的一致性,说明将该程序应用于EAST装置中杂质输运模拟的合理性.并利用DIVIMP程序预测EAST在8MW加热功率条件下钨杂质的输运特性.     

时间推进法求解离心泵内部不可压流场

本文使用时间推进法求解离心泵内部不可压缩流的紊流时均Reynolds方程。选用Boldwin-Lomax双层代数紊流模型,对流项采用中心差分格式离散,时间推进项选用四阶显式Runge-Kutta求解方法。对离心泵在0.4、1.0、1.5倍的设计工况点进行了数值计算。计算所得到的流量扬程点与实验值相吻合,在小流量工况点效率吻合很好,在设计工况和大流量工况点效率偏高,文中讨论了叶轮出口压力分布、蜗壳外壁面上的静压分布及载荷随叶轮半径的变化规律。     

切线泵整机多相位定常流动数值模拟

本文对一单级切线泵在设计工况进行了多相位定常流动数值模拟,分析了由于叶轮与蜗壳相对位置的变化引起的泵的扬程、叶轮流道内的质量流量、速度场、压力场的变化规律。计算表明,切线泵内流场非常复杂,整机多相位定常流动数值模拟的结果实际上是泵内流场非定常特性在定常计算中的反映,其内部流动呈周期性变化,叶轮流道在不同的位置流动情况差别很大。本次计算为进一步提高切线泵性能、减少水力损失提供了一定的理论依据。     

离心泵流量突增过程瞬态流动研究

为研究离心泵流量突增过程所表现的外部瞬态水力特性及其内部流动机理,对离心泵在管路阀门突然开启条件下的特性进行数值模拟和实验研究。测试了不同稳定流量下的离心泵外特性和内流场,验证了稳态工况下的仿真结果。在稳态实验与仿真的基础上,利用分离涡模型(DES)对离心泵流量突增过程的流场进行了数值模拟研究。结果表明,流量突增的瞬态过程的流量-扬程曲线明显偏离稳态值,其主要原因是流量变化引起的流体加速效应及泵内的旋涡结构的不断演化。     

Simulation of Kelvin-Helmholtz Instability with Flux-Corrected Transport Method

The sixth-order accurate phase error flux-corrected transport numerical algorithm is introduced, and used to simulate Kelvin-Helmholtz instability. Linear growth rates of the simulation agree with the linear theories of Kelvin Helmholtz instability. It indicates the validity and accuracy of this simulation method. The method also has good capturing ability of the instability interface deformation.     

基于键合图法的叶片泵启动特性仿真

采用功率键合图法对叶片泵启动过程进行动态特性仿真,结合叶片泵系统内部的能量供给、传递、转化、消耗等要素建立描述叶片泵启动过程的键合图,并基于键合图建立状态方程组进而求解。介绍了叶片泵启动试验装置和试验方法,给出了试验结果,并将数值仿真的结果与试验结果进行比较。仿真结果和试验结果在启动过程整体趋势上以及各参数变化过程上都能够较好的吻合,说明基于键合图法的数值仿真能较好预测叶片泵启动过程的动态特性。     

垂直转子轴式黏性泵内部流动LBM模拟

为了对垂直转子轴式黏性泵内部流动规律进行研究,采用格子Boltzmann法（LBM）对该泵模型全流场进行了数值模拟。采用具有二阶精度的弯曲固壁边界：条件和基于插值公式的移动固壁边界条件,对具有圆形、矩形及方形等3种不同截面形状转轴的模型泵内部定常与非定常流动进行了计算,得到了模型泵体出口剖面处。方向速度分量平均值。结果表明,具有圆形截面形状转轴的泵送效果较另两种截面形状的转轴为佳,计算所得的出口剖面处X方向速度分量平均值与文献中实验结果吻合良好。     

不同离散格式下的离心泵内部流动数值模拟研究

为研究离散格式对离心泵性能预测精度的影响,本文以自吸式离心泵为计算模型,采用Realizable k-ε湍流模式进行三维内流场的数值模拟研究,分析了从零流量到最大工作流量下的内部流动和水力性能。建立了考虑内部间隙影响的自吸式离心泵全三维计算模型,分析了动量方程对流项采用一阶差分和二阶差分格式对计算精度的影响,同时分析了压力项的Standard和PRESTO离散格式对计算精度的影响。结果表明,在小流量工况下,采用二阶迎风格式具有较高的计算精度,而在大流量工况下采用一阶迎风格式更为合适。该结果可为准确预测离心泵全工况外特性提供参考依据。     

LD-pumped Nd:YAG/LBO 556 nm yellow laser

A new laser transition at 1112 nm was obtained after analyzing the parameters of the main laser transitions in Nd:YAG and calculating the transmission loss of the cavity at 1064, 1319, and 946 nm. The maximum output power of the fundamental wavelength was 610 mW, the fundamental wavelength light-to-light conversion efficiency was 38.1%, the maximum output at 556 nm was 109 mW intra-cavity frequency doubled by LBO, the SHG conversion efficiency was 17.8%, and the overall light-to-light efficiency was 6.8% for the pump power of 1.6 W.     

Friction coefficients and directed motion of asymmetric test particles

The behavior of a test particle in a rarefied gas of classical particles is investigated. considering different interaction mechanisms (specular and diffuse reflection, respectively). For large mass ratio between test and gas particles, analytical expressions for the linear friction coefficient are derived. Moreover, the existence of directed motion of asymmetric test particles with distinct initial conditions (but in the absence of any gradients) is shown. The analytical results are supported by a numerical simulation technique applicable to systems with any mass ratio, which is described here in detail.     

电介质/半导体结构样品电子束感生电流瞬态特性

电子束照射下电介质/半导体样品的电子束感生电流(electron beam induced current,EBIC)是其电子显微检测的重要手段.结合数值模拟和实验测量,研究了高能电子束辐照下SiO2/Si薄膜的瞬态EBIC特性.基于Rutherford模型和快二次电子模型研究电子的散射过程,基于电流连续性方程计算电荷...     

Changes of properties of the soliton with temperature under influences of structure disorder in the α-helix protein molecules with three channels

The changes of property of solitons in α-helix protein molecules with three channels under influences of fluctuations of structure parameters and thermal perturbation of medium are extensively investigated using dynamic equations in the improved theory, numerical simulation and Runge-Kutta method. In this investigation the peculiarities of the solitons are given first in the motions of short-time and long-time and its collision features at T = 0 K and biological temperature T = 300 K. This study shows that the solutions of dynamic equations are solitons, which are very stable at T = 0 and 300 K, although its amplitudes and velocity are somewhat decreased relative to that at T = 0 K, the soliton can transport over 1000 amino acid residues, its lifetime is, at least, 120 ps. Subsequently, studies are made of the changes of properties of the soliton with variations of temperature of the medium and fluctuations of structure parameters including mass sequence of amino acid residues and the coupling constant, force constant, dipole–dipole interaction, chain–chain interaction and ground state energy in the α-helix proteins. The investigations indicate that the soliton has high thermal stability and can transport along the molecular chains retaining amplitude, energy and velocity, although the fluctuations of the structure parameters and temperature of the medium increase continually. However, the solitons disperse in larger fluctuations at T = 300 K and higher temperatures than 315 K. Thus it is determined that the critical temperature of the soliton is 315 K. Finally reasons are given for the generation of high thermal stability of the soliton and the correctness of the improved model is demonstrated. It is concluded that the soliton in the improved model is very robust against structure disorder and thermal perturbation of the α-helix protein molecules at 300 K, and is a possible carrier of bio-energy transport, and the improved model is maybe a candidate for the mechanism of this transport.     

双向竖井贯流式水泵装置内部湍流流动分析

基于三维雷诺平均Navier-Stokes方程、标准k-ε紊流模型和SIMPLE算法,首先对一模型泵内部流场进行了数值计算,计算值和试验值吻合较好,验证了计算方法的可行性。进而模拟了双向竖井贯流式水泵装置内部的三维粘性流场。分析了不同工况下水泵装置内部速度场和压力场的分布,计算了水泵装置各段水力损失,预测了在不同叶片安放角时排水工况和引水工况的水泵装置性能。为深入了解双向竖井贯流水泵装置内部流动特性、提高装置的性能提供确实有效的物理信息。     

HT—6M托卡马克欧姆加热下氧杂质的输运模拟

本文利用HT-6M托卡马克上现有的实验数据,对氧杂质进行了输运模拟,给出了HT-6M托卡马克在欧姆加热下氧杂质的输运特性,空间分布和辐射能量。     

带有蓄热装置的直膨式太阳能热泵系统的模拟研究

介绍了一种带有相变蓄热装置的直膨式太阳能热泵系统。以青岛天气为例,对该系统的蓄热模式进行数值模拟,得出蓄热装置进出口制冷剂的温度、蓄热材料的液相率随时间的变化,结果表明在太阳能辐射量变化时,该系统的蒸发温度维持25℃左右,系统能够稳定运行;对系统热力学性质进行理论计算得出系统在冷凝温度为70℃时,系统的COP能维持在5.3左右,系统能够高效运行。     

混流泵叶轮内空化流动的数值计算

本文应用三维Navier-Stokes方程和k-ε两方程湍流模型以及全空化模型,对一台喷水推进混流泵叶轮内的空化流动进行数值模拟.介绍了空化流动的模拟方法,并计算了混流泵的空化性能指标,有效地预测了叶片上空化发生的区域和空化流动的发展情况.文中还对两种进口相对流动角作了数值计算,结果表明小的相对流动角可以提高混流泵的空化性能,但却使扬程有所下降.