Physical and experimental calibration of a mathematical model of the low-pressure-vaporization of free water

摘要

This paper reports the procedure used for the calibration of a mathematical model of the low-pressure-vaporization in free water previously developed by the authors. This calibration includes the determination of the time to the flash point, the time to the transition between the first and the second boiling regimes, the difference between the liquid-vapor interface pressure and the pressure experimentally measured in the free space of the vacuum chamber, which allows the definition of the vaporization coefficient s, and the volume of the vaporization layer. The influence of the initial volume and temperature of the water on these parameters is also determined. For this purpose, a set of multivariable functions are determined from a series of experiments, with different initial water temperatures and volumes. The experimental set-up comprises two main components: the vacuum chamber (VC) and the depres-surization system (DS). Part of the VC volume is occupied by an open container for the water, which is isolated from the VC walls. Two different containers are used having different surface areas and heights, both with a negligible heat capacity. The results obtained show that the functions determined for all the referred parameters are in a good agreement with the experimental results.