Transient Heat Transfer into Liquid Helium under Controlled Heat Generation

Presented here are the results of the experimental study of transient thermal processes taking place in response to a heat disturbance at the interface of “solid - liquid helium”. A feature of the experiment performance is that the thermal power generated in a heater is strictly controlled in time in accordance with a preset rule. The data we report are for a heat load input as a single trapezoidal pulse. The results demonstrate a significant effect of the power pulse leading edge time on the heat transfer dynamics. Established here is a universal character of the map of transient heat transfer modes. A method is proposed which allows for accurate determination of transient characteristics, pattern boundaries, e.g. crisis moment and boiling-up point.