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Introduction
Published in Steven G. Penoncello, Thermal Energy Systems, 2018
While the real fluid model is meant to represent the real behavior of a fluid, it is entirely possible that an equation of state is not accurate. Consider the case of water. There have been several equations of state published for water over the years. The International Association for the Properties of Water and Steam (IAPWS) is an international consortium that reviews equations of state for water and recommends which one will be used as the international standard. The current IAPWS equation of state for water (Wagner and Pruss 2002) is much more accurate compared to equations of state 40 to 50 years previous. However, there are still tables of water properties available based on the old formulations. When designing or analyzing thermal energy systems, the most accurate model should always be used.
Force-System Resultants and Equilibrium
Published in Richard C. Dorf, The Engineering Handbook, 2018
IAPWS (International Association for Properties of Water and Steam) - compiles thermodynamic and transport properties of water and steam (steam tables) and properties of chemical solutions relevant to steam generation, organizes periodic conferences, recommends research.
Exergy Analysis and Thermodynamic Optimization of a steam power plant- Based Rankine cycle system Using Intelligent Optimization Algorithms
Published in Australian Journal of Mechanical Engineering, 2022
Samad Elahifar, Ehsanolah Assareh, Rahim Moltames
In order to calculate and optimise the exergy of the power plant, pressure, temperature, enthalpy, and entropy have been calculated according to IAPWS IF-971 in MATLAB software and in accordance with the mass and energy balance, exergy has been calculated in all parts of the plant. IAPWS IF-97 is a new formulation for the calculation of the thermodynamic properties of water and steam for industrial uses (primarily the steam power industry). This formulation improves significantly the accuracy and speed of the calculations simultaneously compared to the previous formulation. According to this formulation method, the valid range of temperature (0T800 for P800 MPa) is divided into five regions and a governing formula is considered for each individual region. Then, the constant values of the governing formulas are calculated using the empirical data (Wagner et al. 2000). Table 2 shows the calculated values for each element of the power plant before optimising (Vandani, Bidi, and Ahmadi 2015). As can be seen in Figure 2, most of the exergy loss is related to the boiler and the boiler should mainly be focused for improvement and optimisation of process. Exergy efficiency is achieved 30.10% using thermodynamic tables of IAPWS IF-97 and with respect to the relationship 10.
Capability Extension of the High-Resolution Thermal-Hydraulic Code ESCOT for Hexagonal Geometry Core Multiphysics Analysis
Published in Nuclear Science and Engineering, 2023
Jorge Gonzalez-Amoros, Marianna Papadionysiou, Seongchan Kim, Han Gyu Joo
The International Association for the Properties of Water and Steam (IAPWS)-based routine is used to determine the water properties. In ESCOT, the vapor is always assumed to be in the saturated condition. Thus, the flow regimes for the precritical heat flux range are considered. The vertical flow regime map as well as the correlations for interfacial heat transfer of RELAP5-3D (Ref. 15) are used.