Thermodynamic Properties and Transport Coefficients of Nitrogen,Hydrogen and Helium Plasma Mixed with Silver Vapor

Species composites of Ag-N2,Ag-H2 and Ag-He plasmas in the temperature range of 3,000-20,000 K and at 1 atmospheric pressure were calculated by using the minimization of Gibbs free energy.Thermodynamic properties and transport coefficients of nitrogen,hydrogen and helium plasmas mixed with a variety of silver vapor were then calculated based on the equilibrium composites and collision integral data.The calculation procedure was verified by comparing the results obtained in this paper with the published transport coefficients on thc case of pure nitrogen plasma.The influences of the silver vapor concentration on composites,thermodynamic properties and transport coefficients were finally analyzed and summarized for all the three types of plasmas.Those physical properties were important for theoretical study and numerical calculation on arc plasma generated by silver-based electrodes in those gases in sealed electromagnetic relays and contacts.     

Thermal radiation properties of PTFE plasma

To illuminate the thermal transfer mechanism of devices adopting polytetrafluoroethylene (PTFE) as ablation materials,the thermal radiation properties of PTFE plasma are calculated and discussed based on local thermodynamic equilibrium (LTE) and optical thin assumptions.It is clarified that line radiation is the dominant mechanism of PTFE plasma.The emission coefficient shows an opposite trend for both wavelength regions divided by 550 nm at a temperature above 15 000 K.The emission coefficient increases with increasing temperature and pressure.Furthermore,it has a good log linear relation with pressure.Equivalent emissivity varies complexly with temperature,and has a critical point between 20 000 K to 25 000 K.The equivalent cross points of the average ionic valence and radiation property are about 10 000 K and 15 000 K for fully single ionization.     

Investigation of structure and mechanical properties of plasma vapor deposited nanocomposite TiBN films

TiBN coatings have huge potential applications as they have excellent properties with increasing modern industrial requirements.Nanocomposite TiBN coatings were synthesized on cemented carbide,high speed steel and Si substrates by using cathodic arc plasma ion plating from pure TiB_2 ceramic targets.The structure and mechanical properties of the TiBN coatings were significantly influenced by the nitrogen partial pressure.Rutherford backscattering spectrometry demonstrates that the nitrogen content of the coating varied from 2.8%to 34.5%and highresolution electron microscopy images reveal that all coatings have the characteristic of nanocrystals embedded in an amorphous matrix.The root-mean-square roughness of the coatings increases from 3.73 to 14.64 nm and the coefficients of friction of the coatings at room temperature vary from 0.54 to 0.73 with increasing nitrogen partial pressure.The microhardness of the coating increases up to 35.7 GPa at 10 seem N_2 flow rate.The smallest wear rate is2.65×10~(-15)m~3 N~(-1)m~(-1)which indicates that TiBN coatings have excellent wear resistance.The adhesion test revealed that the TiBN coatings have good adhesion at low nitrogen partial pressure.     

Evaluation of phosphate thermodynamic properties for spent electrolyte recycle

Adaptation of the phosphate conversion technique was undertaken and evaluated for application to the recycle process of the spent electrolyte generated from metal electrorefining process. In order to confirm the conversion behaviors of fission product (FP) chlorides to the phosphates, conversion experiments were carried out for some alkali metal, alkaline earth metals and rare-earth elements and their results were compared with that of thermodynamic calculations of previous study [I. Amamoto, H. Kofuji, M. Myochin et al., in: Proceedings of Global 2007, Boisi, Idaho, USA, 2007]. Among these elements, rare-earth chlorides were converted into phosphates and Cs was not, according to the prediction by the calculation. As for alkaline earth metals, their equilibrium constants were nearly 1 based on the results of the calculations, the conversion reactions were difficult to occur. In addition, it was clarified that phosphates were thermally unstable, easily to decompose at higher temperature, through the measurements of their heat flow and vapor pressure.     

Thermodynamic properties and equations of state for fast reactor safety analysis: Part I: Analytic equation-of-state model

Numerical simulation of postulated severe-accident sequences in liquid-metal fast reactors (LMFRs) requires thermodynamic properties of reactor-core materials over wide temperature and pressure ranges. Here an improved analytic equation-of-state (EOS) model using flexible thermodynamic functions is newly developed for a multiphase, multicomponent fluid-dynamics code for LMFR safety analysis. Extension of a van der Waals type equation for vapor phase is also proposed to include the dimerization process of sodium vapor and thereby enables us to predict sodium vapor properties with adequate accuracy. The present EOS model is designed to have adequate accuracy at high temperature and high pressure and to consistently satisfy basic thermodynamic relationships over a wide temperature range without deterioration of the computing efficiency. The newly introduced fluid-dynamic algorithm for pressure iteration consistently coupled with the EOS model is also described in the present paper.     

Thermodynamic properties and equation of state of liquid lead and lead-bismuth eutectic

Since the 1950s, liquid lead (Pb) and lead-bismuth eutectic (Pb-Bi) have been studied in the USA, Canada and in the former-USSR as potential coolants for nuclear installations due to their very attractive thermophysical and neutronic properties. However, experimental data on the thermal properties of these coolants in the temperature range of interest are still incomplete and often contradictory. This makes it very difficult to perform design calculations and to analyse the normal and abnormal behaviour of nuclear installations where these coolants are expected to be used. Recently, a compilation of heavy liquid metal (HLM) properties along with recommendations for its use was prepared by the OECD/NEA Working Party on Fuel Cycle (WPFC) Expert Group on Lead-Bismuth Eutectic Technology. A brief review of this compilation and some new data are presented in this article. A set of correlations for the temperature dependence of the main thermodynamic properties of Pb and Pb-Bi(e) at normal pressure, and a set of simplified thermal and caloric equations of state for the liquid phase are proposed.     

Thermodynamic and Transport Properties of Real Air Plasma in Wide Range of Temperature and Pressure

Air plasma has been widely applied in industrial manufacture. In this paper, both dry and humid air plasmas' thermodynamic and transport properties are calculated in temperature300–100000 K and pressure 0.1–100 atm. To build a more precise model of real air plasma, over 70 species are considered for composition. Two different methods, the Gibbs free energy minimization method and the mass action law method, are used to determinate the composition of the air plasma in a different temperature range. For the transport coefficients, the simplified Chapman-Enskog method developed by Devoto has been applied using the most recent collision integrals. It is found that the presence of CO_2 has almost no effect on the properties of air plasma. The influence of H_2O can be ignored except in low pressure air plasma, in which the saturated vapor pressure is relatively high. The results will serve as credible inputs for computational simulation of air plasma.     

Calculation of thermodynamic parameters of U–Pu–N system with carbon and oxygen impurities

Mixed nitride fuels are being considered for advanced FBR, but very little is known about the thermodynamic properties of these fuels. For an overall composition of the nitride fuel with small amounts of oxygen and carbon impurities, thermodynamic properties, e.g. carbon activity and partial pressures of nitrogen, carbon-monoxide, plutonium and uranium, were calculated in present work. These calculations were based on standard Gibbs free energies of the binary compounds, present in this multi-component system (U,Pu)–C–N–O. For an over all composition of the fuel, stable phase-field was determined by minimization of the Gibbs free energy of the system. The fabrication experiences of various workers, reported in literature, have shown that depending on the impurity content, nitride fuel can exist in two phase fields, mono-nitride phase in equilibrium with sesquinitride phase or mono-nitride phase in equilibrium with dioxide phase. Therefore, in present calculations special attention was given to the thermodynamic behavior of these two phase-fields. A comparison of calculated thermodynamic properties indicated that nitride fuel with dioxide as second phase will be superior to the one with sesquinitride.     

Plasma Formed in Argon,Acid Nitric and Water Used in Industrial ICP Torches

Inductively coupled plasmas (ICPs) are used in spectrochemical analyses.The in-troduction of the sample by means of an aerosol are widely used.The introduction and the total evaporation of the aerosol is required in order to obtain a good repeatability and reproducibility of analyses.To check whether the vaporization of the aerosol droplets inside the plasma is completed,a solution could be used to compare the experimental results of the emission spectral lines with theoretical results.An accurate calculation code to obtain monatomic spectral lines intensities is therefore required,which is the purpose of the present paper.The mixtures of argon,water and nitric acid are widely used in spectrochemical analyses with ICPs.With these mixtures,we calculate the composition,thermodynamic functions and monatomic spectral lines intensities of the plasma at thermodynamic equilibrium and at atmospheric pressure.To obtain a self sufficient paper and also to allow other researchers to compare their results,all required data and a robust accurate algorithm,which is simple and easy to compute,are given.     

A comparison of predictions of high-temperature steam properties

Recent literature pertaining to high temperature steam properties has been assessed. After careful assessment of available sets of property tables and equations for high temperature (including dissociated) steam, a set of high temperature steam properties was selected, based heavily on Vargaftik steam tables. A computer code, UODH2O (University of Ottawa Dissociated H₂O code) is constructed to compute high-temperature steam properties using a lookup table and interpretation technique. The code, which required input values of pressure (0.01–100.0 MPa) and temperature (1000–5726.85°C), can predict four thermodynamic properties - specific volume, entropy, enthalpy and heat capacity, and two transport properties - viscosity and thermal conductivity.     

One-step phenol production from a water–toluene mixture using radio frequency in-liquid plasma

The objectives of this research were to understand the process of converting toluene into phenol in a one-step process directly from a water–toluene mixture using the plasma in-liquid method.Experiments were conducted using 27.12 MHz radio frequency(RF) in-liquid plasma to decompose a solution of 30% toluene. Based on the experimental results as evaluated using gas chromatography–mass spectrometry(GC–MS), along with additional analysis by the Gaussian calculation, density functional theory(DFT) hybrid exchange–correlational functional(B3LYP)and 6-311 G basis, the phenol generated from toluene was quantified including any by-products.In the experiment, it was found that OH radicals from water molecules produced using RF inliquid plasma play a significant role in the chemical reaction with toluene. The experimental results suggest that phenol can be directly produced from a water–toluene mixture. The maximum phenol yields were 0.0013% and 0.0038% for irradiation times of 30s and 60s,respectively, at 120 W.     

Estimation of plasma parameters in the process of micro-scale powder plastic and characteristics of its products

The temperature and density of plasma jets were estimated with a Boltzmann plot and Stark broadening of Ar I (696.54 nm) lines by optical emission spectroscopy (OES) in the process of plasma plastic, and the morphology and microstructure of tungsten (W) powders were investigated by scanning electron microscope (SEM) and x-ray Diffraction (XRD), respectively. The results show that the assumption of local thermodynamic equilibrium (LTE) was invalid at the end of the plasma jets, and earlier than this after the injection of tungsten powder. The temperature and electron density of the plasma jets were up to about T=6797 K with Q_c=50 slpm and n_e=1.05×10¹⁶ cm⁻³ with Q_s=115 slpm at Z=60 mm, respectively, and both dropped rapidly with the injected tungsten powders of 20 μm. After the plasma plastic process, the spherical tungsten powders were prepared and there were some satellite particles on the surface of the spherical products. The tungsten powders were both composed of a single equilibrium α-W phase with a body centered cubic (bbc) crystal structure before and after plasma treatment.     

Equations of state and spinodal lines — a review

Modern thermal processes in the power industry involve ever increasing heat fluxes and rapid transients. Simulating such processes requires accurate thermodynamic properties and correlations that encompass stable as well as metastable states. Here we review the development of cubic equations of state that can be made to yield very accurate thermodynamic properties of liquids in saturation and metastable (superheated) states. These cubic equations enable us to develop predictions and correlations for a number of other quantities which are either useful in themselves or for application to boiling and two-phase flow. Examples of such results include predictions of the saturation pressure, the limiting liquid superheat, the destructive energy available to a superheated liquid, the surface tension of a saturated fluid and the approach of the specific heat at constant pressure to infinity at the spinodal point. These topics are described and discussed, and it emerges that these seemingly separate topics can be unified by the use of cubic equations of state. We pay particular attention to the issue of a possible connection between the limit of liquid superheat and the liquid spinodal line.     

氢-苯乙烯体系中氢-氚同位素交换反应的热力学研究

采用6-311G全电子基函数和B3p86方法对聚苯乙烯-二乙烯基苯(polystyrene-divinylbenzene,SDB)单体之一的苯乙烯分子结构进行优化计算.根据热力学原理,计算得到SDB官能团分子氢氚取代反应在不同温度下的标准生成自由能函变、反应平衡常数及氚气和氢气的反应平衡压力比.结果表明,温度的升高不利于氢氚取代反应T2(g) SDB(H2)(s)→H2(g) SDB(T2)(s)正向进行,这与Pt/SDB疏水催化剂在氢-水同位素交换的催化反应实验过程中的氢氚取代研究结论一致.     

Design,simulation and construction of the Taban tokamak

This paper describes the design and construction of the Taban tokamak, which is located in Amirkabir University of Technology, Tehran, Iran. The Taban tokamak was designed for plasma investigation. The design, simulation and construction of essential parts of the Taban tokamak such as the toroidal field(TF) system, ohmic heating(OH) system and equilibrium field system and their power supplies are presented. For the Taban tokamak, the toroidal magnetic coil was designed to produce a maximum field of 0.7 T at R?=?0.45 m. The power supply of the TF was a130 kJ, 0–10 kV capacitor bank. Ripples of toroidal magnetic field at the plasma edge and plasma center are 0.2% and 0.014%, respectively. For the OH system with 3 kA current, the stray field in the plasma region is less than 40 G over 80% of the plasma volume. The power supply of the OH system consists of two stages, as follows. The fast bank stage is a 120 μF, 0–5 k V capacitor that produces 2.5 kA in 400 μs and the slow bank stage is 93 mF, 600 V that can produce a maximum of 3 kA. The equilibrium system can produce uniform magnetic field at plasma volume. This system's power supply, like the OH system, consists of two stages, so that the fast bank stage is 500 μF, 800 V and the slow bank stage is 110 mF, 200 V.     

Plasma properties of laser-ablated St target in air

Ｐｌａｓｍａｐｒｏｐｅｒｔｉｅｓｏｆｌａｓｅｒ－ａｂｌａｔｅｄＳｔｔａｒｇｅｔｉｎａｉｒＷａｎｇＸｉａｎｇ－Ｔａｉ（王象泰）；ＭａｎＢａｏ－Ｙｕａｎ（满宝元）；ＷａｎｇＧｏｎｇ－Ｔａｎｇ（王公堂）；ＦａｎＸｉ－Ｊｕｎ（樊锡君）；ＷａｎｇＪｕｎ（王军）...     

CPR1000全厂断电叠加蒸汽发生器安全阀误开启事故引起的严重事故分析

利用MELCOR程序对CPR1000全厂断电叠加蒸汽发生器(SG)安全阀误开启事故引发的严重事故进行建模与分析,初步实现了对CPR1000严重事故进程的仿真计算与模拟。文中重点分析了无轴封泄漏和辅助给水、有轴封泄漏和辅助给水、有轴封泄漏但无辅助给水3种不同假设条件下CPR1000全厂断电严重事故的响应进程和结果。计算结果显示,SG安全阀误开启对事故进程有重要影响。在无轴封泄漏和辅助给水的情况下,压力容器在9576 s失效;当存在辅助给水时,压力容器失效延后近30000 s;而当存在轴封泄漏时,压力容器失效延后50 s左右。结果证明了发生全场断电叠加SG安全阀误开启事故情况下辅助给水和轴封泄漏对事故起到有效缓解作用。     

Experimental investigation on the evolution of plasma properties in the discharge channel of a pulsed plasma thruster

Pulsed plasma thrusters(PPTs) are an attractive form of micro-thrusters due to advantages such as their compactness and lightweight design compared to other electric propulsion systems.Experimental investigations on their plasma properties are beneficial in clarifying the complex process of plasma evolution during the micro-second pulse discharge of a PPT. In this work, the multi-dimensional evolutions of the light intensity of the PPT plasma with wavelength, time, and position were identified. The plasma pressure was obtained using an iterative process with composition calculations. The results show that significant ion recombination occurred in the discharge channel since the line intensities of CII, CIII, CIV, and FII decreased and those of CI and FI increased as the plasma moved downstream. At the center of the discharge channel, the electron temperature and electron density were in the order of 10 000 K and 10~(17) cm~(-3),respectively. These had maximum values of 13 750 K and 2.3?×?10~(17) cm~(-3) and the maximum temperature occurred during the first half-cycle while the maximum number density was measured during the second half-cycle. The estimated plasma pressure was in the order of 10~5 Pa and exhibited a maximum value of 2.69?×?10~5 Pa.     

Kinetic equilibrium reconstruction for the NBI-and ICRH-heated H-mode plasma on EAST tokamak

The equilibrium reconstruction is important to study the tokamak plasma physical processes.To analyze the contribution of fast ions to the equilibrium,the kinetic equilibria at two time-slices in a typical H-mode discharge with different auxiliary heatings are reconstructed by using magnetic diagnostics,kinetic diagnostics and TRANSP code.It is found that the fast-ion pressure might be up to one-third of the plasma pressure and the contribution is mainly in the core plasma due to the neutral beam injection power is primarily deposited in the core region.The fast-ion current contributes mainly in the core region while contributes little to the pedestal current.A steep pressure gradient in the pedestal is observed which gives rise to a strong edge current.It is proved that the fast ion effects cannot be ignored and should be considered in the future study of EAST.     

Thermodynamic Study of Water-Steam Plasma Pyrolysis of Medical Waste for Recovery of CO and H2

This paper describes the equilibrium compositions of the typical medical waste under high temperature pyrolysis by a steam plasma torch using the NASA CEA2 program. Various components from selected typical medical waste were input to the program along with the treatment temperature from 1000 K -4100 K. The program then performed the Gibbs free energy calculations and searched for the equilibrium composition with minimizing the total system Gibbs free energy. The calculation results indicate that, the equilibrium composition of a system C-H-O at C/O = 1 in the temperature range of 1400 K - 2000 K has demonstrated that gas composition are CO and H2 mainly, the other components （CO2, C2H4, C2H2, CH4 etc.） is less than 1% by volume and the degree of raw material transformation is about 100%. Comparison with air plasma, the steam plasma treatment will not produce nitrogen oxides, if the materials are free of nitrogen element.