Quantification of boiling flows in single and multiple heater rods assembly by recurrence plots and recurrence quantification analysis

Abstract

Tracer particle position time series obtained by RPT experiments were used to quantify the changes in hydrodynamics induced by boiling flows in single and multiple rods assembly. The test section under consideration is a “scaled-down” version of a typical boiling water nuclear reactor (Advanced Heavy Water Reactor (AHWR) of the Department of Atomic Energy, India). The analysis of the above-mentioned time series was done by Recurrence Plots (RP) and Recurrence Quantification Analysis (RQA). Visual differences in the RPs were detected with changes in the inlet condition and heater rods configuration. The constructing feature of the recurrence plot can be categorized in two forms: local white areas (LWA) and local bold areas (LBA). However, the change cannot be quantified by visual observation, and for this quantification RQA parameters such as Recurrence Rate (RR), Determinism (DET), and Entropy (ENT) were used. Experimental results show that the increase in liquid flow rate, decrease in inlet liquid temperature, and increase in the number of the heater rods caused increased RR, increased DET, and increased ENT.