Online calculation method of enthalpy-entropy values of water and water vapor

Abstract

The invention discloses an online calculation method of enthalpy-entropy values of water and water vapor. Based on an industrial calculation model IAPWS-IF97 formula and a Symphony system of the water and the water vapor, the method comprises the following steps of: firstly, measuring temperatures and pressures of the water and the water vapor by a sensor in real time and judging areas corresponding to the water and the water vapor according to the temperatures and the pressures; and then calculating the enthalpy-entropy values of the water and the water vapor according to the formulas of the corresponding areas of the water and the water vapor. According to the method provided by the invention, the enthalpy-entropy values of the water and the water vapor can be calculated in real time; and meanwhile, the method further has the advantages of high precision, less calculation time consumption, wide applicable range and the like. The method provided by the invention can be used for monitoring a production process, in which the water and the water vapor are utilized as working media, in real time.

Description

technical field [0001] The invention belongs to a calculation method of thermal coefficient, in particular to an online calculation method of water and steam enthalpy entropy. Background technique [0002] Water vapor is the earliest working medium used by humans in the indirect utilization of heat energy. The steam is closer to the liquid state, the force between the microscopic particles is strong, and the molecules themselves occupy a considerable volume, and there are often state changes between the gas and the liquid during the working process. Therefore, steam cannot be treated as an ideal gas. Its physical properties are much more complicated than that of an ideal gas, and its equation of state, thermodynamic properties, enthalpy and entropy are not as simple as those of an ideal gas. Generally, the engineering calculation of steam directly accesses the steam thermodynamic property chart prepared for engineering calculation or calls the steam thermodynamic property s...

AI Technical Summary

Problems solved by technology

The limitation of this method is that the accuracy of the calculation results depends on the choice of software, and the process is complicated and the operability is poor.

[0005] The above two methods for calculating the enthalpy and entropy of water and water vapor are only obtained manually based on existing off-line data, or by manually inputting water in a computer application program. and water vapor measurement parameters, but cannot be obtained online, resulting in the inability to obtain real-time enthalpy and entropy values ​​of water and water vapor

In actual industrial production, for the production process using water and steam as the working medium, such as the online performance monitoring of embedded thermal power plant units based on Symphony, the off-line method for determining the enthalpy and entropy of water and steam cannot obtain the required thermal parameters in real time , so that the online performance calculation of the entire unit cannot be completed

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