Interface Waves at a Stagnation Point in Free Convection Film Boiling (An Experimental Study)

摘要

An experimental investigation was conducted concerning the origin and behavior of the interface waves observed in free convection film boiling at a stagnation point. Wave frequency and vapor layer thickness were measured by photographic and optical methods respectively for models of four different stagnation point geometries in subcooled water. Model and bulk liquid temperatures were measured and used to compute system thermal parameters. Model temperature was varied between 800 and 1600F. Bulk liquid temperature was held nearly constant in the vicinity of 160F. The waves were found to originate at the stagnation point. Their frequency was found to be a decreasing function of the temperature difference between the model wall and the interface. The data strongly indicate that frequency is an increasing function of surface to volume ratio at the stagnation point. A correlation among frequency, vapor layer thickness, stagnation point geometry and system thermal parameters was attempted but was not successful. It is believed that this is due at least in part to the high uncertainties encountered in measuring vapor layer thicknesses by the techniques of this experiment. (Author)