5,174 research outputs found
Sensitivity analysis on the instability of the natural circulation in a thermosiphon loop
No full textDuring the period 1993 -2004, D’Auria had the opportunity to cooperate with the University of Genova (noticeably Prof. Misale). This cooperation brought to a valuable contribution to the scientific community based on the characterization of the single phase instabilities in a simple atmospheric pressure ‘glass’ loop previously available by UNIGE and upgraded within the framework of the cooperation with UNIPI. The characterization of the loop performance and the analysis of performed experiments were performed by the help of system thermal-hydraulic codes; those analyses confirmed some early investigations results by Velander in 1968.
The present paper deals with the application of RELAP to the analysis of unstable experimental data in the UNIGE loop
Analysis of single phase natural circulation experiments with Cathare v1.3u and Relap5/mod3.2 codes
No full textDuring the period 1993 -2004, D’Auria had the opportunity to cooperate with the University of Genova (noticeably Prof. Misale). This cooperation brought to a valuable contribution to the scientific community based on the characterization of the single phase instabilities in a simple atmospheric pressure ‘glass’ loop previously available by UNIGE and upgraded within the framework of the cooperation with UNIPI. The characterization was made with the help of system thermal-hydraulic codes and confirmed some early investigation results by Velander 1968.
The present document deals with the application of both RELAP and CATHARE to the analysis of unstable experimental data in the UNIGE loop and was performed in the framework of a cooperation with the Argentinean government institution CNEA (Commission for Nuclear Energy in Buenos Aires)
Experimental study on the influence of power steps on the thermohydraulic behavior of a natural circulation loop
No full textSingle phase natural circulation is a heat transfer mechanism of great interest in various energy systems, including solar heaters, nuclear reactors, geothermal power production, engine and computer cooling. The present paper deals with an experimental study on the influence of power steps on the behavior of a single-phase natural circulation loop. In particular two sets of experiments were performed: constant power and variable power. Several parameters such as the amplitude of power steps as well as the period of the oscillations were experimentally investigated. The runs at constant power were carried out at different power levels from 500 W to 3000 W. The experiments at variable power were carried out for the values of 500 W, 1000 W, and 2000 W. The amplitude of steps was ±50% or ±20% of the input power, whereas the period of the oscillations varied between 50 s and 7200 s. All tests, both at constant power and variable power, show always an unstable behavior, i.e., temperature oscillations across the heated sections occur in the fluid. Moreover, the amplitude and the frequency of the oscillations increase as the input power increases. The thermal inertia of the loop plays a role in case of smaller time steps
Sull’accumulo termico di pareti interne: valutazione della partecipazione al regine variabile per differenti sollecitazioni termiche
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Dynamic behaviour of a single-phase natural circulation loop : influence of heat sink temperature
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