The Effect of Liquid and Wall Properties Toward the Increase of Wetting Velocity in the Case of Using Multiple Plates in the Top-Reflood Vertical Surfaces

Abstract Rewetting is an important mechanism in the quenching process, particularly in the case of nuclear reactor safety. During the Loss-of-coolant accident (LOCA) in the Emergency Core Cooling System (ECCS) of the nuclear reactor. In the location near the wetting front, heat transfer coefficient (HTC) increases, and the quenching rate also occurs rapidly. The mechanism of wetting velocity on the case of 2 (two) plates is assumed to be different compared to 1 (one) plate. The test section consists of two metal plates which are used as the heat transfer surface. Each of up and down edges of the metal plates (brass or copper) was sandwiched by the brass block columns. The block columns are set to heat the plate until the temperature of 250–300 °C. Meanwhile, distilled water is sprayed through the nozzle onto one or two plates. Furthermore, wetting velocity is calculated using the video captured by infrared camera FLIR™ to observe the liquid motion on the heated wall. Several parameters are being observed, including the effect of mass flux, initial wall temperature, thermal conductivity, wall thickness, and subcooled degree. The results show the significance of droplets impact for cooling the wall, thus contributes to higher wetting velocity in the case of multiple plates.