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ENCIT 2016
16th Brazilian Congress of Thermal Sciences and Engineering
EXPERIMENTAL STUDY OF TWO-PHASE FLOW OSCILLATIONS IN A NATURAL CIRCULATION LOOP
Submission Author:
André Luiz Braucks Vianna , RJ
Co-Authors:
Su Jian, José Luiz Horacio Faccini, André Luiz Braucks Vianna
Presenter: André Luiz Braucks Vianna
doi://10.26678/ABCM.ENCIT2016.CIT2016-0083
Abstract
This work aims to investigate experimentally the oscillations observed during the operation of a natural circulation loop, designed to meet the single and two-phase flow similarity criteria to a typical Passive Residual Heat Removal (PRHR) system of an Advanced Pressurized Water Nuclear Reactor (APWR). The loop was one-tenth scale in height and operated at atmospheric pressure. It was comprised of a cylindrical vessel with descending tube, a core barrel housing electrically heated rods, and upper and lower plena interconnected to a seven-tube shell heat exchanger by hot and cold pipe legs. A data acquisition and control system was provided, including a power control and instrumentation, in order to permit variations of the power to the electrically heated rods, as well as to acquire flow rate, pressure and temperature data in a timely manner. The results obtained, especially in terms of temperature and flow rate oscillations, indicated that the loop was subject to a condition of cyclic two-phase flow instability. It was characterized by the periodic repetition of the same pattern of changing in the temperature, flow rate and other important flow characteristics, like the sequence of two-phase flow patterns during the instability period.
Keywords
natural circulation, natural circulation loop, Convecção Natural, Two-phase Flow, Convective Instability, natural circulation, natural circulation loop, Convecção Natural, Two-phase Flow, Convective Instability
