Data-driven optimization study of the multi-relaxation-time lattice Boltzmann method for solid-liquid phase change

Sharp phase interfaces and accurate temperature distributions are important criteria in the simulation of solid-liquid phase changes.The multi-relaxation-time lattice Boltzmann method(MRT-LBM)shows great numerical performance during simulation;however,the value method of the relaxation parameters needs to be specified.Therefore,in this study,a random forest(RF)model is used to discriminate the importance of different relaxation parameters to the convergence,and a support vector machine(SVM)is used to explore the decision boundary of the convergent samples in each dimensional model.The results show that the convergence of the samples is consistent with the sign of the decision number,and two types of the numerical deviations appear,i.e.,the phase mushy zone and the non-physical heat transfer.The relaxation parameters chosen on the decision boundary can further suppress the numerical bias and improve numerical accuracy.

Study on Phase Equilibrium Properties for CO_(2)^+ Cosolvent Binary Systems

In this study, the constant volume, visual method is used to measure the critical point of CO_(2)+toluene, CO_(2)+cyclohexane, CO_(2)+n-butyraldehyde, CO_(2)+i-butyraldehyde, CO_(2)+methanol and CO_(2)+alcohol binary systems. The relationship between critical point and the concentration of the entrainer for different substances has been discussed, and the comparison of the phase behavior of single component system and that of binary systems have been carried out.

Equilibrium Diagram in the Presence of a Gaseous Phase and Its Application(Overview Part Ⅰ)

ＥｑｕｉｌｉｂｒｉｕｍＤｉａｇｒａｍｉｎｔｈｅＰｒｅｓｅｎｃｅｏｆａＧａｓｅｏｕｓＰｈａｓｅａｎｄＩｔｓＡｐｐｌｉｃａｔｉｏｎ①（ＯｖｅｒｖｉｅｗＰａｒｔⅠ）ＺｈａｎｇＨｅｍｉｎｇａｎｄＤｕＡｉｌｉｎｇ（张鹤鸣）（杜爱玲）ＣｈｅｍｉｃａｌＥｎｇｉｎｅ...

Calculation of the Phase Equilibrium of CO2–Hydrocarbon Binary Mixtures by PR-BM EOS and PR EOS

The phase equilibrium data of CO2 hydrocarbon binary mixtures are important for the design and operation of CO 2 ood- ing, coal liquefaction, and supercritical extraction processes. Numerous pieces of binary phase equilibrium data have been obtained. Thus, models for the accurate calculation of binary and multicomponent mixtures must be developed on the basis of existing data. In this work, 3578 vapor liquid phase equilibrium data points for 10 CO 2 hydrocarbon binary mixtures, including CO2 butane, CO 2 pentane, CO 2 isopentane, C O 2 hexane, CO 2 benzene, CO 2 heptane, CO 2 octane, C O 2 non- ane, CO 2 decane, and C O 2 undecane, were collected. The PR and PR-BM equations of state (EOS) in combination with relevant mixing rules were used to calculate the phase equilibrium data of the CO 2 hydrocarbon binary mixtures. The binary interaction parameter k ij in the PR EOS was temperature independent, whereas parameters in the PR-BM EOS were functions of temperature. Thus, the phase equilibrium data and other thermodynamic properties of the binary and multicomponent mixtures at di erent temperatures and pressures can be calculated by using the parameters obtained in this work. The PR-BM EOS performed better than the PR EOS, and the average absolute deviations over the temperature range of 255.98 408.15 K calculated by the PR EOS and PR-BM EOS were less than 5.74% and 3.36%, respectively. The results calculated by the two EOS were compared with those calculated by other models, such as PPR78, PR + LCVM + UNIFAC, KIE + PR EOS + HV, and PSRK. The phase equilibrium data of CO 2 butane decane, CO 2 hexane decane, and C O 2 octane decane ternary mixtures were calculated by the two EOS. The average overall deviations for the CO 2 mole fractions calculated by the two EOS were less than 7.66%.

PHASE EQUILIBRIUM FOR THE TERNARY SYSTEM VINYL CHLORIDE-CHLORINATED POLYETHYLENE-POLY(VINYL CHLORIDE)

Swelling capacity of vinyl chloride (VC) in chlorinated polyethylene (CPE) with 25—40 wt% Cl at temperature 30—57℃was studied and their relationships were correlated with Langmuir and Freundlich adsorption equations. A ternary phase diagram for VC-CPE-PVC was also established. In-situ polymerization conditions of CPE-g-VC were proposed and CPE content control was analyzed for the manufacturing process of CPE-g-VC graft product based on results of phase equilibrium study.

Discussion on the Non-Equilibrium Phase of the Gliding Arc Plasma Driven by the Transverse Magnetic Field

A gliding arc driven by the transverse magnetic field was ignited between the elec-trodes with a complicated shape at atmospheric pressure and a non-equilibrium plasma was gen-erated.Under our experimental conditions,a phenomenon was clearly observed where the arcpower decreased with the increase in arc voltage.As the arc voltage was higher than 3.375 kV,the arc power acquired from the power supply decreased,and the arc plasma began to switch toa non-equilibrium phase.The existence of the non-equilibrium arc plasma was very short,about10 ms in one gliding arc discharge cycle.

Phase Equilibrium of Isobutanol in Supercritical CO2

Vapor-liquid phase equilibrium data including composition,densities,molar volume and equilibrium constant of isobutanol in supercritical carbon dioxide from 313.2K to 353.2K were measured in a variable-volume visual cell.The properties of critical point were obtained by extrapolation.The results showed that critical temperature,critical pressure and critical compressibility factor of CO2-isobutanol system decreased with the increase of critical CO2 content.The phase equilibrium model was established by Peng-Robinson equation of state and van der Waals-2 mixing regulation,and model parameters were determined by optimization calculation of nonlinear least square method.The correlation between calculated values and the experimental data showed good agreement.

Non-equilibrium State Salt-forming Phase Diagram：Utilization of Bittern Resource in High Efficiency

Salt-forming regions for a complex salt-water system in non-equilibrium state of evaporation process are usually different from those in solubility diagrams.To understand the solid-forming region of NaCl and improve the utilization of bittern resources,experiments were carried out to evaporate 20 representative mixture solution samples of Na +,Mg 2+ //Cl-,2 4 SO-H2O system with an average evaporation intensity of(1.4±0.4) g·L-1 ·min-1(water) at boiling temperature 348 K,and determine the NaCl solid-forming regions in non-equilibrium state.Because of the complexity of salt-forming region,a maximal region and a minimal region were proposed to express the non-equilibrium state salt-forming region with different crystal seed,and a conditional salt-forming region was proposed to present the characteristic region of non-equilibrium salt-forming phase diagram.The areas of the maximal and minimal regions are 2.00 and 1.56 times those in solubility diagram,so it is possible to utilize bittern resources in high efficiency.The recovery rates of NaCl were 99.65%,93.14%,88.57%,72.76%,and 83.68%for six typical bittern sources from Tulantai Salt Lake(China),Dongtai Salt Lake(China) ,Jilantai Salt Lake(China),Qarun Salt Lake(Egypt) and seawater,respectively.It is testified that the non-equilibrium state salt-forming phase diagram can be used in industrial processes.

Phase Equilibrium of Mg-Zn-La System in Mg-Rich Corner from 200 to 350 ℃

Alloys of Mg-Zn-La system in Mg rich corner were prepared, and the phase relationship was investigated at different temperatures such as 200, 300 and 350 ℃ by scanning electron microscopy(SEM), X-ray diffraction(XRD) and electron probe microanalysis with energy dispersive X-ray spectroscopy (EPMA). Two types of phase equilibrium were identified at the different temperatures. One is two-phase equilibrium contained the Mg solid solution and T-phase. The other is three-phase equilibrium which contained the Mg solid solution, MgZn phase and T-phase. T-phase was stable as the temperature changed. The La content in T-phase is constant which is about 8±0.3% (atom fraction); but the Mg content and Zn content of that is changed, and the Zn content in T-phase was from 16.1% to 44%. The solubility of La in MgZn phase was increased from 1.2% to 1.6% as the temperature increasing from 200 to 350 ℃.

NON-CUBIC EQUATION OF STATE FOR PHASE EQUILIBRIUM CALCULATIONS

A new non-cubic equation of state is proposed for calculation of the thermodynamic properties ofnonpolar and polar fluids and their mixtures,including,saturated vapor pressure,saturated liquid volume,saturated vapor volume,heats of vaporization and vapor-liquid equilibria.The new equation is derived from thegeneralized van der Waals partition function in which the repulsive terms are expressed with the Carnahan andStarling equation for hard spheres,and the attractive terms are made up of the dispersive energy and theChemical association energy. The rules of dependence of parameters α and σ and on temperature are considered broadly so that the newequation yields good agreement with experimental saturated properties of 20 nonpolar and 27 polar fluids in therange of reduced temperatures of 0.5 to 1.0 The new equation with parameters group-contributed generally givessatisfactory predictions on saturated properties. Correlations of vapor-liquid equilibrium data for alcohol-containing systems by using van

LOCAL EQUILIBRIUM METHOD IN STUDYING PHASE DIAGRAM OF Mn-MnO SYSTEM

A special method based on the local equilibrium principle has been introduced in the researchof the phase diagram of Mn-MnO system.With this method,the problems of volatilization ofMn and the corrosion of Mn and MnO to refractory materials were prevented efficiently.Thesolubility of oxygen in Mn and the composition of the interface between MnO and Mn weredetermined.Partial phase diagram of Mn-MnO system were constructed according to pres-ent experimental results.

PHASE EQUILIBRIUM OF COMPLEX MIXTURES WITH EQUATIONS OF STATE:AN UPDATE

Here we review a new class of mixing rules that have extended range of mixtures and condi-tions that can now be described by equation of state models.One characteristic of these mixing rulesis that they simultaneously satisfy the boundary conditions of producing a second virial coefficientthat is quadratic in mole fraction,and a free energy of mixing like that of an activity coefficientmodel at high density,though the mixing rule is itself independent of density.We show that usingthis mixing rule,various asymmetric,highly nonideal mixtures can be accurately described.Oneserendipitous result is that the parameters in this mixing rule model are almost independent oftemperature,which allows accurate extrapolations of phase behavior to be made over large ranges oftemperature and pressure.

Stable Phase Equilibrium of the Aqueous Ternary System Li+//Cl-,borate- H2O at 348 K

The Sichuan Basin,with an area of about 20×104 km2,is situated at 102.5°~110°E and 27.67°~32.67°N.The underground brine resources in Sichuan basin are a type of comprehensive liquid mineral resource.

Equilibrium Diagram in the Presence of a Gaseous Phase and Its Application(Overview Part Ⅱ)

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EQUILIBRIUM PHASE DIAGRAMS IN SYSTEM CuO-PbO-Ag

ＥＱＵＩＬＩＢＲＩＵＭＰＨＡＳＥＤＩＡＧＲＡＭＳＩＮＳＹＳＴＥＭＣｕＯ－ＰｂＯ－Ａｇ￥ＳＨＡＯＺｈｏｎｇｂａｏ；ＬＩＵＫｕｉｒｅｎ；ＭＥＮＧＢｏ；ＬＩＹｉｎｇ；ＹＡＮＧＹｕｑｉｎｇ（ＤｅｐａｒｔｍｅｎｔｏｆＣｈｅｍｉｓｔｒｙ，Ｎｏｒｔｈｅａｓｔｅｒｎ...

EFFECTS OF ENTRAINERS ON THE PHASE EQUILIBRIUM OF SUPERCRITICAL FLUID EXTRACTION PROCESS

A flow apparatus was set up for measuring the solubility of a solid solute in a supercritical fluid withthe presence of a small amount of entrainer.The solubilities of biphenyl,diphenylamine and benzoic acid insupercritical carbon dioxide with one of the selected entrainers which were ethanol,acetone and n-hexanerespectively,were obtained in the pressure range of 10—32 MPa and the temperature range of 308—318K.Asolvolytic association theory has been proposed to explain the mechanism of entrainer effect,and theexperimental results were reasonably analysed.According to the solvolytic association theory,the association equa-tion of state was adopted to correlate the experimental data with good accuracy.

Phase Equilibrium of Ternary Systems LaX_3-C_(18)H_(16)N_3O_2Cl-H_2O

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Solid-Liquid Phase Equilibria in the Aqueous System Containing Potassium,Magnesium,and Borate at 308.15 K

Experimental studies on the solubility, density, refractive index, and pH value in the aqueous system containing potassium, magnesium, and borate at 308.15 K were determined with the method of isothermal dissolution equilibrium. Based on the experimental results, the diagrams of solubility, density, refractive index, and pH value in this system were plotted. We found that there were one eutectic point and two crystallization regions corresponding to the large area of inderite (L + Mg2B6O11·15H2O) and the relatively small area of potassium borate tetrahydrate (L + K2B4O7 ·4H2O), respectively. Neither double salt nor solid solution was found in this system. The physicochemical properties (density, refractive index, and pH value) in solution at 308.15 K changed regularly with increasing potassium borate concentration. The calculated values of density and refractive index using empirical equations of the aqueous system were in good agreement with the experimental values.

The Solid-liquid Transformation of Low-grade Solid Potash Deposit in Dalangtan Basin and the Simplification of the Liquid Phase System

We studied the solid-liquid transformation of low-grade solid potash deposit in Dalangtan Basin and simplified the liquid phase system.We did experiments to optimize conditions of the solid-liquid transformation.The

PHASE EQUILIBRIUM OF SBCL3-HCL-H2O SYSTEM

ＰＨＡＳＥＥＱＵＩＬＩＢＲＩＵＭＯＦＳｂＣｌ３－ＨＣｌ－Ｈ２ＯＳＹＳＴＥＭＤｕａｎ，Ｘｕｅｃｈｅｎ；Ｚｈａｎｇ，Ｄｕｏｍｏ；Ｚｈａｏ，Ｔｉａｎｃｈｏｎｇ（ＣｅｎｔｒａｌＳｏｕｔｈＵｎｉｖｅｒｓｉｔｙｏｆＴｅｃｈｎｏｌｏｇｙ，Ｃｈａｎｇｓｈａ４１００８...