Abstract: By using a spline function for curved surface used in simulating the bending of a plate to describe the ternary excess free enthalpy function Q, a new indirect method for calculating ternary vapor composition y from T, p and liquid composition x was established. Broyden-Nowton-Raphson iteration procedure was used for solving the nonlinear equations. The calculation of 30 ternary systems from nearly ideal to highly nonideal phase behavior showed that this new method was very stable and reliable. The calculated results were in good agreement with the experimental data. More-over, this method had a variety of distinguishing features such as good convergence, no special requirement for initial values and little influence caused by neglecting the excess properties during calculation.

摘要： 采用模拟平板弯曲变形的曲面样条函数表达三元系过量自由焓函数Q,由此建立了一个在汽液平衡中由T、p、x数据推算y的间接算法.非线性方程组的求解采用Broyden改进的Newton—Raphson迭代程序,经过30个从接近理想到高度非理想的不同类型三元系的检验结果表明,本方法计算结果可靠,与实验值符合良好.本方法还具有算法稳定、对初值要求不高及收敛速度快、过量性质影响小等特点.