Real-time control algorithm of International Association for the Properties of Water and Steam (IAPWS)-IF 97 based on thermal properties of water and steam

The invention provides real-time control algorithm of International Association for the Properties of Water and Steam (IAPWS)-IF 97 based on thermal properties of the water and the steam. The algorithm carries out modular processing on a formula of the IAPWS-IF 97 from engineering practical, safe and reliable angles, can finish calculation of the thermal properties of normally-seen water and steam under the condition of small load calculation, is suitable for being applied to finishing the high-accuracy calculation of the thermal properties of the water and the steam in various process control systems, is particularly specific to needs of monitoring operation of a supercritical unit with variable-pressure operation at present, and makes up the defects of a function of online calculation of the thermal properties of the water and the steam of an exiting automatic control system.