Quasi-steady front in quench subcooled-jet impingement boiling: Experiment and analysis

Boiling heat transfer of subcooled water jet impingement on highly superheated plate is investigated with heat transfer analysis and high-definition flow visualization. The stainless steel plate initially heated up to 900 °C by an induction heating is quenched with the water temperature of 15 °C. The surface temperature and heat flux are estimated by solving 2-D inverse heat conduction problem. The temporal visualization during quench subcooled-jet impingement boiling is synchronized with the heat transfer measurement in the corresponding surface temperature and heat flux. Spread of the subcooled jet over the horizontal plate shows a quasi-steady regime where the wetting front spreads linearly with time. The time for onset of the quasi-steady regime can be explained by a quasi-steady time. The front separates the single-phase/collapsed-bubble region from the outside region which is dry if not for the impinging droplets ejected from the front. As the front expands, the surface experiences a sequence of single-phase, collapsed-bubble, wetting front evaporation and ejected-droplet evaporation cooling. The fraction of water ejected from the front increases linearly with time (reaches over 10%) and is also predicted.