EXPLICIT FROST-KALKWARF TYPE EQUATIONS FOR CALCULATION OF VAPOUR PRESSURE OF LIQUIDS FROM TRIPLE TO CRITICAL POINT BY THE ADOMIAN DECOMPOSITION METHOD

The general form of explicit, analytical solution of the Frost-Kalkwarf equation was developed for the first time by means of the Adomian decomposition method as a reliable mathematical tool. The accuracy of the obtained formulas was further improved by applying the diagonal Pade approximants. We have demonstrated that our developed formulas are at least 30 times faster than the original Frost-Kalkwarf equation in computation of vapour pressures and are highly accurate with an overall absolute relative deviation of 2.25 % for 88 different substances over 26 400 experimental data points from triple to critical point temperatures. As another unique advantage, our formulas avoid any divergent behaviour in using iterative methods unlike the implicit Frost-Kalkwarf equation. Based on the conducted statistical analyses, our formulas have excellent predictability of vapour pressure values with a probability of 90.33 % for absolute relative errors of less than 5 %.