Mathematical modeling of unbounded spaces using single-equation-based point saturated steam water spaces

Abstract

Purpose Industries, especially power plants, using steam as power fluid employ many equipment and systems using saturated steam. Mathematical modeling of this saturated steam water space (SSWS) equipment is important for simulators catering to these industries and power plants. Single-equation-based modeling approach and its optimized version, mass factor–volume factor approach, are very efficient in modeling SSWS with bounded volumes, where the volume of the space is fixed. In unbounded volumes, the volume may be changing or is unbounded because of expansion, contraction or pressure control. The purpose of this paper is to propose a single equation based modeling approach for unbounded SSWS. Such unbounded volumes are encountered in coolant channels of pressurized heavy water reactor (PHWR)-type nuclear power plants (NPPs). Design/methodology/approach This paper proposes an extension of a single-equation approach by considering a subsection of the volume as miniature Point SSWS. In the proposed Point SSWS, the total heat, mass and volume of the SSWS are delinked and overall density and heat density are introduced in place. With this extension, Point SSWS can be applied to unbounded volumes. Findings In this study, 392 coolant channels of proposed 680 MWe PHWR have been simulated to ascertain the overall coolant density when coolant boils partially on nuclear heating. The simulation results have been compared with simulation results available from previous researchers and it has been found that the values are in line with previous researchers with maximum deviation of 1.2 per cent. Originality/value From the simulation results and their low value of deviation, it is clear that point space approach can be effectively used in modeling Point SSWS. Moreover, theoretically, it has been proved that the density of homogenous steam–water mixture is dependent only on the bulk heat density and temperature of the mixture.