A Fundamental Equation for Calculation of the Thermodynamic Properties of Ethanol

A formulation for the thermodynamic properties of ethanol (C₂H₅OH) in the liquid, vapor, and saturation states is presented. The formulation is valid for single-phase and saturation states from 250 to 650K at pressures up to 280MPa. The formulation includes a fundamental equation and ancillary functions for the estimation of saturation properties. The experimental data used to determine the fundamental equation include pressure-density-temperature, ideal gas heat capacity, speed of sound, and vapor pressure. Saturation values computed from the ancillary functions were used to ensure thermodynamic consistency at the vapor-liquid phase boundary. Comparisons between experimental data and values computed using the fundamental equation are given to verify the uncertainties in the calculated properties. The formulation presented may be used to compute densities to within ±0.2%, heat capacities to within ±3%, and speed of sound to within ±1%. Saturation values of the vapor pressure and saturation densities are represented to within ±0.5%, except near the critical point.     

制冷系统仿真中的工质热力性质计算程序

制冷系统仿真中必然用到工质热力性质计算程序,本文针对制冷系统中常用到的9种工质进行了热力性质分析,利用VB6.0编写了其计算程序模块,并在实际的制冷仿真系统中得到了应用,最终通过动力实验平台的测试,证实计算程序是合理的.     

制冷系统仿真中的工质热力性质计算程序

制冷系统仿真中必然用到工质热力性质计算程序,本文针对制冷系统中常用到的9种工质进行了热力性质分析,利用VB6.0编写了其计算程序模块,并在实际的制冷仿真系统中得到了应用,最终通过动力实验平台的测试,证实计算程序是合理的.     

Crossover SAFT Equation of State and Thermodynamic Properties of Propan-1-ol

In this work we have developed a new equation of state (EOS) for propan-1-ol on the basis of the crossover modification (CR) of the statistical-associating-fluid-theory (SAFT) EOS recently developed and applied to n-alkanes. The CR SAFT EOS reproduces the nonanalytical scaling laws in the asymptotic critical region and reduces to the analytical-classical SAFT EOS far away from the critical point. Unlike the previous crossover EOS, the new CR SAFT EOS is based on the parametric sine model for the universal crossover function and is able to represent analytically connected van der Waals loops in the metastable fluid region. The CR SAFT EOS contains 10 system-dependent parameters and allows an accurate representation of the thermodynamic properties of propan-1-ol over a wide range thermodynamic states including the asymptotic singular behavior in the nearest vicinity of the critical point. The EOS was tested against experimental isochoric and isobaric specific heats, speed of sound, PVT, and VLE data in and beyond the critical region. In the one-phase region, the CR SAFT equation represents the experimental values of pressure with an average absolute deviation (AAD) of less than 1% in the critical and supercritical regions and the liquid densities with an AAD of about 1%. A corresponding states principle is used for the extension of the new CR SAFT EOS for propan-1-ol to higher n-alkanols.     

制冷工质R22热力性质的一种快速算法

制冷工质热物性的计算是数值模拟技术非常重要的一个环节，开展这一工作的研究且有重要的价值。本文在结合Martin-Hou方程的基础上提出了制冷工质热力性质的一种快速算法，经实例验证，该算法具有精度高、适应范围广、稳定性好等特点，可供制冷工质热物性算法设计的初学者作参考。     

基于Pandat的Ti-Al系相图计算及热力学评估

基于相图计算理论,用Pandat 2016热力学计算软件、最新的钛合金数据库和热力学模型,计算研究了Ti-Al二元系相图。从相律、相图的特殊点、各相存在的范围、相变点等方面对其进行了详细的热力学评估。计算结果表明:计算相图和实验相图吻合得较好,其相对误差基本都在5%以内,为推广到三元或更高元体系相图奠定了基础。随后提出了一个新的计算Ti-Al二元系中(α+β)/β相变点的公式,其置信度为99.982%,与经验计算公式相比,计算更为准确,具有一定的参考价值和学术交流意义。     

二元微合金碳氮化物化学组成与固溶度的热力学计算以及钢材化学成分的影响规律

采用热力学计算方法推导出二元微合金碳氮化物的化学组成及有关元素在奥氏体中的固溶度的理论计算式,由此从理论上深入分析讨论了钢材化学成分对二元微合金碳氮化物化学组成的影响规律并导出一些重要的结论。     

An Assessment of Thermodynamic Models for HFC Refrigerant Mixtures Through the Critical-Point Calculation

An assessment of thermodynamic models for HFC refrigerant mixtures based on Helmholtz energy equations of state was made through critical-point calculations for ternary and quaternary mixtures. The calculations were performed using critical-point criteria expressed in terms of the Helmholtz free energy. For three ternary mixtures: difluoromethane (R-32) + pentafluoroethane (R-125) + 1,1,1,2-tetrafluoroethane (R-134a), R-125 + R-134a + 1,1,1-trifluoroethane (R-143a), and carbon dioxide (CO₂) + R-32 + R-134a, and one quaternary mixture, R-32 + R-125 + R-134a + R-143a, calculated critical points were compared with experimental values, and the capability of the mixture models for representing the critical behavior was discussed.     

在爆破设计中基于组合优化的一个新的计算公式

基于超图的性质,提出了一个在爆破设计中由经验公式和经验数据组成的通用的计算公式。当一个目标函数值可由许多公式估算时,它可以选出最好的几个分配问题的模型被用来做更准确地分析,新公式在爆破块度分布的计算中被验证。     

Review of the Thermodynamic Properties of Hydrogen Based on Existing Equations of State

Currently available equations of state (EOSs) for hydrogen are reviewed, and the data for the critical point, normal boiling point, and triple point are summarized. Through comparisons of PVT, saturated properties, heat capacity, and speed of sound among the latest EOSs for hydrogen, their features are discussed. The proper use of the EOSs, including a consideration of the nuclear isomers (ortho- and parahydrogen), is of great importance, especially for saturated properties, heat capacity, and speed of sound because these properties are different between the nuclear isomers. The present review concludes with recommendations for use of the EOSs for hydrogen.     

Calculation of the Velocity of Second-Order Thermal Slip Using the Model Kinetic Equation with a Variable Collision Frequency

The problem on the calculation of the second-order thermal slip velocity is solved. For this purpose, an exact solution of an inhomogeneous model Boltzmann kinetic equation with the collision operator in the form corresponding to the BGK model with the collision frequency proportional to the module of intrinsic velocity of gas molecules is constructed. Comparison with the available results is performed.     

The Correlation between the Thermodynamic Functions of Molten Binary Systems of Alkali Metals

Differential thermodynamic equations are used to reveal, in the general form, the correlation between some excess thermodynamic functions of liquid solutions. It is demonstrated that a certain correlation is observed in wide ranges of temperature and concentrations between the calculation and experimental data on excess molar enthalpy and specific volume of molten Na-K and K-Cs systems.     

基于微扰理论的静电电子透镜的缺陷电场计算

研究了用于计算电子光学系统的缺陷电场和容差的微扰理论。基于微抗原理，推导了计算静电电子透镜由于电极偏心、倾斜和加工不圆造成的电场变化及其旁轴多极场展开函数的九点有限差分公式，编制了计算软件。建立了两个电场解析模型，通过该模型的解析解与数值计算结果的对比，证实了算法及软件的正确性，并据此讨论了微扰理论用于容差计算的适用范围。计算了几个静电电子透镜的例子，给出了不同电极缺陷的电位分布和微扰多极场分布。     

二元金属类水滑石的合成及其作为前驱体对NOx的吸附性能研究

用共沉淀法合成了多种二元金属类水滑石化合物,对其进行了XRD、IR表征,并测试了焙烧产物对NOx的吸附性能.结果表明,合成的样品都具有典型的水滑石层状结构;二元金属类水滑石化合物MAl-HTlcs(M=Cu,Mg,Zn,Co,Ni)对NOx均具有良好的吸附性能,其中锌铝型类水滑石(摩尔比Zn/Al=3)对NOx的吸附速率及饱和吸附量最大,饱和吸附量为1851mg/g.     

An Equation of State for the Hard-Sphere Chain Fluid Based on the Thermodynamic Perturbation Theory of Sequential Polymerization

New equations of state for freely jointed hard-sphere chain fluids are developed. The equations of state are based on the thermodynamic perturbation theory. The new equations of state use the contact values of the radial distribution function (RDF) for monomer–dimer mixtures, which is derived from the multidensity Ornstein–Zernike theory. These RDFs are composed of a monomer reference term, the Carnahan–Starling or the Percus–Yevick expression, and an additional bond contribution. These equations of state are then extended to real fluids. To calculate the phase equilibrium properties of nonassociating chain fluids, a dispersion contribution is added to the repulsive hard-chain reference term. With the new equations of state of chain fluids supplemented with the dispersion term, the vapor pressures and the coexisting densities of several real fluids are calculated.     

30Cr3Si2Mn2NiNb钢中未溶相的热力学计算及分析

采用Thermo-Calc热力学软件模拟了30Cr3Si2Mn2NiNb钢奥氏体化时平衡相的演化规律以及非平衡态相的演化规律,研究了合金元素C,Mo,Nb和V对实验钢中未溶相的影响.通过SEM,XRD对30Cr3Si2Mn2NiNb钢淬火态组织进行实验观察及分析.结果表明:常规奥氏体化处理后,钢中未溶相主要有富Nb的M...     

基于水位控制的膨胀水箱选型计算新方法

在总结相关手册对膨胀水箱选取计算方法的基础上,针对计算方法存在的缺陷性,从控制水箱水位的角度出发,提出了膨胀水箱选择计算的新方法;结合不同水系统,总结了相关数据,供设计参考。     

基于无量纲模型的直接蒸发冷却填料性能计算与分析

在BorisHalasz提出的适用于蒸发冷却设备通用数学计算模型基础上,考虑了因水蒸发或者凝结而引起水的质量变化对于系统的影响,建立了更加符合实际应用情况的直接蒸发冷却（DEC）填料的数学计算模型。并利用该模型探讨了蒸发冷却填料的性能及内部温度分布,同时对填料的结构参数以及运行条件进行了优化。     

Calculation of the Optical Properties of Quartz Ceramics Based on Data on Its Structure

The optical parameters of quartz ceramics from a previously proposed identification method and simulation using different optical models of the material are compared. The identification method is based on deliberately measuring hemispherical spectral reflectances for layers of different thicknesses and solving the inverse problem using asymptotic formulas. Mathematical models are constructed based on the Mie theory on the assumption of independent scattering of electromagnetic radiation by fragments of the material. The material is considered as a polydisperse packing of spheres, the sizes of which are determined by data on the material structure. Both a grain surrounded by gas and a pore in monolithic material are considered as a scatterer. Data on the material structure were gathered using optical microscopy, static laser scattering, and mercury porosimetry. The best agreement with the results of the identification method is demonstrated by the model of ceramics in the form of a glass monolith with spherical voids. Comparative analysis eliminates uncertainty in the form of the scattering phase function and shows that the scattering is close to isotropic.     

金属纳米微粒热力学性能的形状效应

金属纳米微粒的热力学性能不仅依赖于纳米微粒的尺寸,还依赖于纳米微粒的形状.介绍了作者建立的描述纳米微粒形状效应的理论模型,该模型能够预测微粒形状对其结合能、熔解温度、过热、熔解熵、熔解焓、空位形成能、空位浓度以及纳米微粒相图的影响.该模型的预测结果和已有的实验数据一致.