Cooling of the hot steel balls by salt -water solutions and water-based suspensions: Subcooled pool boiling experiments

摘要

In this work, the subcooled pool boiling experiments are performed during the intense cooling of the heated metal balls made of carbon steel AISI 1044 and stainless steel AISI 420L by brines and water-based suspensions of graphite and clay. The heated metal balls with an initial temperature of 1000 K are cooled down with a rate up to 300-450 K/s during the initial 2-4 s. The measured results show that a change in the mass fraction of the solid admixtures in a coolant affects the cooling process insignificantly. The phenomenon of the "step" change of the vapor film thickness during the pool film boiling of the subcooled deionized water at the surface of the immersed metal ball are discussed in detail. The brines and water-based suspensions utilization as coolants enables to eliminate the film boiling of the subcooled liquid. Besides, the optical method of the planar laser-induced fluorescence is applied to measure the temperature distributions near the liquid/vapor interface emerged when the heated metal ball is cooled down in a liquid pool.