Investigation of Liquid Vaporization Characteristics at Low–Pressure Conditions

An experimental study has been implemented to examine water pool sudden flash evaporation in a cuboidal chamber. Some key parameters have been studied such as initial vacuum tank pressure, superheat, and initial water temperature. The initial water volume is set to one liter only. Initial conditions of the liquid vary from 50 °C to 85 °C temperature and vacuum tank pressure 6.33 kPa and 20.63 kPa (abs.) which corresponds to 2 °C to 38 °C superheat. Moreover, the influence of these key parameters on the thermo- properties like water pool temperature, mass evaporated, nonequilibrium fraction (NEF), and heat transfer coefficient (h) are analyzed. The experimental results showed that lower vacuum tank pressure and greater superheat have larger impact on flashing phenomenon. Results suggested that a larger value of the NEF and h take place at the beginning of the flash. The value of heat transfer coefficient found to be time dependent function tends to decrease with flash time passes.