Masters Degrees (Mechanical and Mechatronic Engineering)
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Browsing Masters Degrees (Mechanical and Mechatronic Engineering) by Author "Abrahams, T."
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- ItemNatural circulation air-cooled two-phase closed-loop thermosyphon heat transfer system(Stellenbosch : Stellenbosch University, 2017-03) Abrahams, T.; Dobson, R. T.; Stellenbosch University. Faculty pf Engineering. Dept. of Mechanical and Mechatronic Engineering.ENGLISH ABSTRACT: This project considers the passive cooling aspects of a small-scale inherently safe, light water, 100 MWe, modular nuclear reactor concept. This concept uses triple containment of the core and consists of three integrated natural circulation loops, namely the primary, secondary and tertiary loops. The tertiary loop was designed, built, commissioned and tested to measure the temperature and flow rate response at different operating conditions. The tertiary loop functioned successfully with the average heat transfer rate out of the air-cooled condensers measured at 89.5% of the electrical power input into the system. A quasi-steady state, three-dimensional, separated flow, thermal-hydraulic numerical simulation of the tertiary loop system is developed. The numerical simulation captures the thermal-hydraulic behaviour of the working fluid within the tertiary loop well. The temperature response has an average error of 5.73% and the mass flow rate has an average error of 1.86%. The simulation can be used with reasonable certainty to determine the behaviour of the tertiary loop for various input values. A steady state numerical simulation model of the primary, secondary and tertiary loops operating together was developed to predict the behaviour of the complete passive cooling system and shows encouraging results. The passive cooling concept can now be scaled to the dimensions of a full size nuclear reactor plant and its thermal-hydraulic behaviour confidently determined using the simulation models developed.