ICONE15-10682 ENTRAINMENT OF WATER AROUND A SINGLE ROD IMMERSED IN WATER POOL WITH GAS JET IMPINGEMENT(II)

Abstract

The occurrence of secondary heat transfer tube failure due to overheating by sodium-water reaction in steam generator of liquid sodium cooled fast breeder reactor has been concerned from the viewpoint of public acceptance. To evaluate the phenomena for the secondary heat transfer tube failure, a sophisticated computer code SERAPHIM has been developed by JAEA. The comparison of simulation results with experimental data to verify the adequacy of SERAPHIM code or to upgrade it are now required. As the first step to verify the adequacy of SERAPHIM code without chemical reactions, a visualization experiment of Ar gas jet impinging a single rod with 20mm in diameter immersed in a water pool was performed in our previous study. The time sequential results showed that the surrounding water is periodically entrained into Ar gas jet because of the organized motions between the gas jet and the surrounding water. The entrained water into gas jet was considered to be effectively contributed to heat transfer characteristics if the single rod is heated. We measured the void fraction around a single rod in the water pool as a basic experiment using the apparatus capable of doing sodium pool experiment to investigate the flow pattern and the water entrainment around a single rod (several millimeters from the rod surface) in this paper. The vertical gas tube with a nozzle at the top was inserted through the bottom of experimental tank. The diameter of nozzle prepared on the top of the tube is 3.5mm. A single horizontal rod immersed in water pool is fixed a distance of 25mm between the nozzle exit and the forward stagnation point of the rod. The Ar gas jet velocity was changed from 17.3m/s to 346m/s. The result of the void fraction reflected the result of the heat transfer experiment that had been reported before was obtained, and a certain prospect of the measurement of the void fraction in sodium pool was obtained.