Accurate prediction of the convective single- and two-phase heat transfer is very important in process and power engineering for reliability, security, and efficiency of related systems and devices. In this aspect, boiling is particularly interesting and complex phenomena, which may significantly enhance the heat transfer from the heated surface to the coolant flow. The detailed understanding of these phenomena is of great importance and, as such, is put under investigation in the THELMA laboratory.
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Picture: Test section consists of specially designed heat exchanger and inlet/outlet legs. (Hint: use the slider)
The main facility is a unique test loop designed for local heat flux measurement in annulus geometry, which resembles a close vicinity of a single fuel rod in the light water reactors - see the Picture. The applied design allows visual observations of various boiling regimes (see the Video) and establishment of accurately controlled environment even at critical heat flux (CHF) conditions.
Video: Various boiling regimes in the horizontal position of the test section. The pictures are taken at 1600 Hz and the video is slowed down for 50-times.
Publications:
ZAJEC, Boštjan, Končar, Boštjan, MATKOVIÄŒ, Marko, CIZELJ, Leon. Experimental investigation of subcooled flow boilingof R245fain a narrow horizontal annular duct, Proceedings of the 5thWorld Congress onMomentum,Heat and Mass Transfer (MHMT'20). DOI: 10.11159/icmfht20.170
ZAJEC, Boštjan, MATKOVIÄŒ, Marko, CIZELJ, Leon. Heat transfer measurements in a single-phase flow of refrigerant R245fa in annular geometry. 28th International Conference Nuclear Energy for New Europe, Portorož, Slovenia, 2019 September 9-12. Conference proceedings.
BASAVARAJ, Anil Kumar, MIKUŽ, Blaž, MATKOVIÄŒ, Marko. Flow and heat transfer CFD analysis in the section of THELMA for wall surface temperature determination. 28th International Conference Nuclear Energy for New Europe, Portorož, Slovenia, 2019 September 9-12. Conference proceedings.
BASAVARAJ, Anil Kumar, ZAJEC, Boštjan, MATKOVIÄŒ, Marko. Accurate measurements of the local heat transfer coefficients along the dedicated test section. 27th International Conference Nuclear Energy for New Europe, Portorož, Slovenia, 2018 September 10-13. Conference proceedings.
ZAJEC, Boštjan, CIZELJ, Leon, MATKOVIÄŒ, Marko. Izdelava testne sekcije za meritve kritičnega toplotnega toka pri izotermnih robnih pogojih. konference mladih jedrskih strokovnjakov : povzetki prispevkov, predstavljenih na konferenci v Reaktorskem centru Podgorica, 26. 2. 2018. 1. izd. Ljubljana: Društvo jedrskih strokovnjakov Slovenije. 2018, str. 26.
MATKOVIÄŒ, Marko, CIZELJ, Leon, KLJENAK, Ivo, KONÄŒAR, Boštjan, MIKUŽ, Blaž, SUŠNIK, Andrej, TISELJ, Iztok, ZAJEC, Boštjan. Building a unique test section for local critical heat flux studies in light water reactor : like accident conditions. HEFAT2017, 13th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Portorož, Slovenia, 2017 July 17-19.
MATKOVIÄŒ, Marko, CIZELJ, Leon, KLJENAK, Ivo, KONÄŒAR, Boštjan, LESKOVAR, Matjaž, PROŠEK, Andrej, TISELJ, Iztok. Designing an advanced experimental test apparatus for conjugate heat transfer studies. SWINTH-16, Specialists Workshop on Advanced Instrumentation and Measurement Techniques for Nuclear Reactor Thermal Hydraulics, Livorno, 2016 June 15-17.
Fast Fourier transform approach to strain gradient crystal plasticity: Regularization of strain localization and size effect
Amirhossein Lame Jouybari, dr. Samir El Shawish and dr. Leon Cizelj from the Reactor Engineering Divis...
Extending intergranular normal-stress distributions using symmetries of linear-elastic polycrystalline materials
Dr. Samir El Shawish from the Reactor Engineering Division at Jožef Stefan Institute published the research artic...