Claim Missing Document
Check
Articles

Found 2 Documents
Search

Investigation of Natural Circulation Flow Under Steady-State Conditions Using a Rectangular Loop Roswandi, Iwan; Dimas, Dimas; Gunawan, Hyundianto Arif; Budiman, Arif Adtyas; Amelia, Almira Citra; Sanda, Sanda; Tjahjono, Hendro; Juarsa, Mulya
JURNAL TEKNOLOGI REAKTOR NUKLIR TRI DASA MEGA Vol 26, No 2 (2024): June 2024
Publisher : Pusat Teknologi Dan Keselamatan Reaktor Nuklir (PTKRN)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55981/tdm.2024.7055

Abstract

Passive safety systems have garnered significant attention, particularly in situations where active systems fail. The comprehension of natural circulation phenomena plays a vital role in the advancement of passive cooling systems in nuclear power plants. The objective of this study is to examine the flow patterns under steady state conditions and assess the Grashof number. The experimental approach involved maintaining temperature differences of 60°C, 70°C, 80°C, and 90°C for a duration of 3 hours, with 3 replications. Alterations in temperature have an impact on the physical properties of water, such as density, viscosity, and specific heat. The calculations indicate that the minimum Grashof number occurs at 60°C (2.49×1012), while the maximum is observed at 90°C (9.42×1012), with an R2 value of 0.96533. Turbulent flow patterns were observed during each temperature fluctuation, which aligns with previous research on the Ress value of Grm/NG.
Effect of water temperature on flow regimes and reynolds number in a passive natural circulation cooling system Setiawan, Putut Hery; Pamitran, Agus Sunjarianto; Yuliaji, Dwi; Pamungkas, Adhika Enggar; Budiman, Arif Adtyas; Amelia, Almira Citra; Maryadi, Shendy Akbar; Irwansyah, Ridho; Juarsa, Mulya
Jurnal Polimesin Vol 23, No 3 (2025): June
Publisher : Politeknik Negeri Lhokseumawe

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30811/jpl.v23i3.6665

Abstract

Natural circulation flow is an important phenomenon of passive cooling systems in nuclear reactor thermal management during accidents. This experimental study investigates the effect of varying water temperatures on flow regimes and Reynolds number within a passive natural circulation system. The research was conducted using a rectangular TP-loop (FASSIP-04 Ver.2) made of 1-inch SS304 pipe, 6 m high and 1.32 m wide. The water temperature setting was varied at 45°C, 55°C, 65°C, and 75°C, with a heating power of 4.2 kW, and the cooling tank was maintained at 10°C. Observations were made during transient heating, steady-state (for 3 hours), and transient cooling phases. Results show that increasing the heating tank temperature reduces fluid density and viscosity, thereby enhancing buoyancy-driven flow. This led to a transition in flow regimes from laminar to turbulent as the temperature increased. The Reynolds number increased by 169.38% when the water temperature was raised from 45°C to 75°C. Unstable flow behaviour, including fluctuating amplitudes and frequencies, was observed—characteristic of natural circulation dynamics. The study confirms a strong correlation between thermal variation and flow regime transition, providing insights into the performance of passive cooling systems under varying thermal loads.