Pool boiling experimental study on the impact of deposition on the nucleate boiling and bubble behavior of horizontally-placed tubes

During the operation of the nuclear reactor, the corrosion particles deposited on the fuel cladding will change surface characteristics and affect the boiling heat transfer. However, due to the intricate structure of the deposition layer, the mechanism of the impact of deposition on nucleate boiling is not clear at present. A pool boiling experiment was carried out to investigate the effect of particle deposition on the bubble behavior and nucleate boiling heat transfer characteristics. The effect of deposition time and heat fluxes on the nucleate boiling was investigated. The effect mechanism of particle deposition on the circumferential heat transfer was revealed. The results indicate that the tube surface becomes more hydrophilic after deposition, and the deposited tube presents a boiling heat transfer state with the down-side surface in the form of large bubbles and the up-side surface in the form of a continuous stream of small bubbles. Furthermore, during the deposition process, the heat transfer coefficient decreases rapidly at the initial period, then increases slightly and stabilizes. Meanwhile, the rod circumferential temperature distribution varied before and after deposition, and the deterioration of the heat transfer coefficient of the up-side surface is more serious due to the influence of gravity deposition. The current tests show that corrosion particle deposition has a great impact on heat transfer, the post-deposition heat transfer coefficient can be reduced to 25% of its original value.