Boiling flow visualization experiment scaled to divertor cooling conditions

Gajšek, Aljoša (avtor), Kozmus, Gregor (avtor), Tekavčič, Matej (avtor), Richou, Marianne (avtor), Končar, Boštjan (avtor)

A dedicated experiment FEDORA (Fusion Experiment for Divertor Optimization Research Applications) has been constructed to visualize flow boiling at scaled fusion divertor conditions. Its main purpose is to obtain the information on local boiling parameters, needed for the development of mechanistic boiling models in Computational Fluid Dynamics (CFD) codes. Current boiling models, although grounded on realistic physical principles, still rely heavily on empirical correlations, particularly for boiling parameters such as nucleation site density, bubble departure diameter, and bubble departure frequency. Due to the harsh operating conditions in the water-cooled divertor plasma-facing components (high heat fluxes over 10 MW/m$^2$, mean flow velocity of about 9 m/s), visualization of boiling in realistic cooling channels is not feasible. The proposed experiment addresses this challenge by employing a surrogate coolant, characterized by lower latent heat and saturation temperature. By analyzing key dimensionless numbers, the aim is to replicate boiling conditions to be similar to those in coolant channels of upcoming divertor designs. Distinctive features of the proposed experimental setup include visually transparent boiling channel, infra-red transparent window and a thin electrically heated foil. This setup allows simultaneous high-speed and high-resolution recording of boiling phenomena in the flow and measurement of temperature distribution on the heated surface. In this work, the design, similarity analysis and the first measurement results are presented, proving the concept of the visualization approach to understand the boiling heat transfer in divertor cooling channels.

• Jezik: Angleški jezik
• Ključne besede: flow boiling, high-heat flux, divertor cooling conditions, visualization experiment, boiling parameters
• Vrsta gradiva: Članek v reviji
• Tipologija: 1.01 - Izvirni znanstveni članek
• Organizacija: FMF - Fakulteta za matematiko in fiziko
• Status publikacije: Objavljeno
• Različica publikacije: Objavljena publikacija
• Leto izida: 2025
• Št. strani: 6 str.
• Številčenje: Vol. 218, art. 115188
• PID: 20.500.12556/RUL-181982
• UDK: 621.039
• ISSN pri članku: 0920-3796
• DOI: 10.1016/j.fusengdes.2025.115188
• COBISS.SI-ID: 238773251
• Datum objave v RUL: 21.04.2026

Gradivo je del revije

• Naslov: Fusion engineering and design
• Skrajšan naslov: Fusion eng. des.
• Založnik: Elsevier
• ISSN: 0920-3796
• COBISS.SI-ID: 15359237

Licence

• Licenca: CC BY-NC 4.0, Creative Commons Priznanje avtorstva-Nekomercialno 4.0 Mednarodna
• Povezava: http://creativecommons.org/licenses/by-nc/4.0/deed.sl
• Opis: Licenca Creative Commons, ki prepoveduje komercialno uporabo, vendar uporabniki ne rabijo upravljati materialnih avtorskih pravic na izpeljanih delih z enako licenco.

Sekundarni jezik

• Jezik: Slovenski jezik
• Ključne besede: jedrska tehnika, vrenje, pretok