Temperature Uniformity Across the Surface in Transition Boiling

The condition under which temperature is kept uniform across the surface in transition boiling is investigated theoretically and numerically. Analysis of three-dimensional heat conduction indicates that an unstable mode emerges depending on the gradient of a boiling curve and dimension and properties of a heater block in steady-state runs. A thinner heated block for the same diameter or larger diameter for the same thickness loses uniformity for a shallower boiling curve in transition boiling. Simulation of a transient run and another analysis indicates that the surface is always kept sufficiently uniform in transient runs without control of heat input. The analysis also reveals the rapid change in the surface temperature in transient runs.