拟合液体饱和蒸气压的新方程

New Equation for Correlating Data of Substance's Saturated Pressure

在已有实验数据的基础上,提出一个拟合液体饱和蒸气压数据的新方程:lnp=(1-x)lnp0+xlnp1+xΣCi(1-xi),并与被认为是最为准确的蒸气压拟合显函数方程Wagner方程进行比较.应用新方程,利用MATLAB6.1软件,拟合149种有机物质共2114个实验点的蒸气压数据,新方程的总平均相对误差(ARD)为0.2625%,而Wagner方程的ARD为1.606%,表明新方程比Wagner方程有了很大的改进.

It is important to describe quantitatively the variation of a substance's saturated pressure with temperature by a suitable equation.For example,it will be possible to calculate other thermodynamics data such as the evaporation heat and viscosity of substances using this kind of equation.The object of this work is to develop such an equation with simple form (therefore we can conduct mathematic operations especially differentiation and integration on it) and satisfactory calculating errors.As a result,a new equation is proposed for correlating data of substance's saturated pressure:lnp=(1-x)lnp_0+xlnp_1+x∑ni=1C_i(1-x^i).(Using MATLAB) 6.1 software,2 114 data of 149 organic substances including paraffin,olefin,aromatic,alcohol,aether,ketone,acid,aldehyde,phenol,butter,amine and cyanogens is correlated by the new equation with total average relative deviation (ARD) equal to 0.262 5%.By comparison,the ARD of well-known Wagner's equation under the same conditions is 1.606%,showing that the new equation is of advancement.