Some successful vapor-liquid equilibrium(VLE) mixing rules based on excess free energy models proposed in recent years combines the advantages owned partially by equations of state and activity coefficient models to o...Some successful vapor-liquid equilibrium(VLE) mixing rules based on excess free energy models proposed in recent years combines the advantages owned partially by equations of state and activity coefficient models to obtain the better prediction for nonpolar and polar systems.The paper coupled with the merits of MHV1 mixing rule, LCVM mixing rule and WS mixing rule to put forward the new two-parameter mixing rule which satisfies the second viral coefficient boundary condition.The new mixing rule, coupled with the PR equation of state and the NRTL model is tested against 18 kinds of vapor-liquid equilibrium data of nonpolar, nonpolar-polar/polar-nonpolar,and polar-polar systems.The test results indicate that the new model can yield better prediction.Compared to the other two mixing rules (WS,MHV1), the new model shows better VLE prediction capabilities of binary mixtures.展开更多
采用温度相关比容平移项的比容平移Soave-Redlich-Kwong(VTSRK)方程计算新工质R1234yf和R1234ze(E)的热力学性质以及两种物质与CO_2的二元混合物性质,混合物计算采用van der Waals混合规则,二元交互作用系数由密度数据拟合得到。对纯净...采用温度相关比容平移项的比容平移Soave-Redlich-Kwong(VTSRK)方程计算新工质R1234yf和R1234ze(E)的热力学性质以及两种物质与CO_2的二元混合物性质,混合物计算采用van der Waals混合规则,二元交互作用系数由密度数据拟合得到。对纯净物计算与专用状态方程进行对比,VTSRK方程比SRK方程显著改善了液相密度表征效果。对混合物的密度计算结果与实验数据进行对比,对于R1234yf+CO_2二元混合体系方程与实验数据相对均方根偏差为1.17%,对于R1234ze(E)+CO_2二元混合体系相对均方根偏差为0.82%。结果显示,采用温度相关比容平移项的VTSRK方程应用于R1234yf和R1234ze(E)纯流体以及R1234yf+CO_2和R1234ze(E)+CO_2密度性质计算,可获得较高精度。展开更多
A generalized corresponding-state model based on two reference fluids was developed for the prediction of surface tensions for non-polar and weakly polar pure fluids and their binary mixtures. Four parameters, p_c, T_...A generalized corresponding-state model based on two reference fluids was developed for the prediction of surface tensions for non-polar and weakly polar pure fluids and their binary mixtures. Four parameters, p_c, T_c, V_c and ω, were used in this model, and the acentric factor ω was used as a scaling parameter. This model has been tested for 69 pure substances and 20 binary mixtures; the average absolute deviations are 0.28 and 0.20 mN/m, respectively. The results indicate that the predictions by means of this model were in good agreement with experimental data. In addition, the calculated deviation would increase with the excess surface tension rising, and if the excess surface tension is less than 3 mN/m, the prediction will be good and credible.展开更多
In this paper we discuss the convergence of the directed graph-algorithm for solving a kind of optimization problems where the objective and subjective functions are all separable, and the parallel implementation proc...In this paper we discuss the convergence of the directed graph-algorithm for solving a kind of optimization problems where the objective and subjective functions are all separable, and the parallel implementation process for the directed graph -algorithm is introduced.展开更多
Two kinds of experimental methods were tried in the present work:(i)the powder metallurgy method combined with differential thermal analysis(DTA)to determine the metastable liquidus miscibility gap for a Fe–Cu binary...Two kinds of experimental methods were tried in the present work:(i)the powder metallurgy method combined with differential thermal analysis(DTA)to determine the metastable liquidus miscibility gap for a Fe–Cu binary system and(ii)the high-temperature melting method combined with isothermal treatment to determine the stable liquidus miscibility gap for a Fe–Sn binary system.The experimental method was adopted according to the characteristics of the liquidus miscibility gap of the specific system.Using the powder metallurgy method,a uniform microstructure morphology and chemical composition was obtained in the DTA specimen,and the phase-separation temperature of the supercooled metastable liquid was measured.The isothermal treatment was applied for the samples inside the stable liquidus miscibility gap;here,equilibrated compositions were reached,and a layered morphology was formed after rapid cooling.The liquid miscibility gaps of the Fe–Cu and Fe–Sn binary systems were measured,and the peak temperatures of the corresponding miscibility gaps were determined to be about 1417°C at x(Cu)=0.465 at%and 1350°C at x(Sn)=0.487 at%,respectively.On the basis of the experimental results,both the Fe–Cu and the Fe–Sn binary systems were thermodynamically assessed.展开更多
文摘Some successful vapor-liquid equilibrium(VLE) mixing rules based on excess free energy models proposed in recent years combines the advantages owned partially by equations of state and activity coefficient models to obtain the better prediction for nonpolar and polar systems.The paper coupled with the merits of MHV1 mixing rule, LCVM mixing rule and WS mixing rule to put forward the new two-parameter mixing rule which satisfies the second viral coefficient boundary condition.The new mixing rule, coupled with the PR equation of state and the NRTL model is tested against 18 kinds of vapor-liquid equilibrium data of nonpolar, nonpolar-polar/polar-nonpolar,and polar-polar systems.The test results indicate that the new model can yield better prediction.Compared to the other two mixing rules (WS,MHV1), the new model shows better VLE prediction capabilities of binary mixtures.
文摘采用温度相关比容平移项的比容平移Soave-Redlich-Kwong(VTSRK)方程计算新工质R1234yf和R1234ze(E)的热力学性质以及两种物质与CO_2的二元混合物性质,混合物计算采用van der Waals混合规则,二元交互作用系数由密度数据拟合得到。对纯净物计算与专用状态方程进行对比,VTSRK方程比SRK方程显著改善了液相密度表征效果。对混合物的密度计算结果与实验数据进行对比,对于R1234yf+CO_2二元混合体系方程与实验数据相对均方根偏差为1.17%,对于R1234ze(E)+CO_2二元混合体系相对均方根偏差为0.82%。结果显示,采用温度相关比容平移项的VTSRK方程应用于R1234yf和R1234ze(E)纯流体以及R1234yf+CO_2和R1234ze(E)+CO_2密度性质计算,可获得较高精度。
文摘A generalized corresponding-state model based on two reference fluids was developed for the prediction of surface tensions for non-polar and weakly polar pure fluids and their binary mixtures. Four parameters, p_c, T_c, V_c and ω, were used in this model, and the acentric factor ω was used as a scaling parameter. This model has been tested for 69 pure substances and 20 binary mixtures; the average absolute deviations are 0.28 and 0.20 mN/m, respectively. The results indicate that the predictions by means of this model were in good agreement with experimental data. In addition, the calculated deviation would increase with the excess surface tension rising, and if the excess surface tension is less than 3 mN/m, the prediction will be good and credible.
文摘In this paper we discuss the convergence of the directed graph-algorithm for solving a kind of optimization problems where the objective and subjective functions are all separable, and the parallel implementation process for the directed graph -algorithm is introduced.
基金supported by National Key Research and Development Program of China (No. 2016YFB0701201)National Natural Science Foundation of China (No. 51271027)
文摘Two kinds of experimental methods were tried in the present work:(i)the powder metallurgy method combined with differential thermal analysis(DTA)to determine the metastable liquidus miscibility gap for a Fe–Cu binary system and(ii)the high-temperature melting method combined with isothermal treatment to determine the stable liquidus miscibility gap for a Fe–Sn binary system.The experimental method was adopted according to the characteristics of the liquidus miscibility gap of the specific system.Using the powder metallurgy method,a uniform microstructure morphology and chemical composition was obtained in the DTA specimen,and the phase-separation temperature of the supercooled metastable liquid was measured.The isothermal treatment was applied for the samples inside the stable liquidus miscibility gap;here,equilibrated compositions were reached,and a layered morphology was formed after rapid cooling.The liquid miscibility gaps of the Fe–Cu and Fe–Sn binary systems were measured,and the peak temperatures of the corresponding miscibility gaps were determined to be about 1417°C at x(Cu)=0.465 at%and 1350°C at x(Sn)=0.487 at%,respectively.On the basis of the experimental results,both the Fe–Cu and the Fe–Sn binary systems were thermodynamically assessed.
