Nucleate Pool Boiling Regimes Of Power Electronics Cooling

The boiling curve of refrigerant FK-649 at a saturation temperature of 36°C is experimentally determined for nucleate pool boiling on the baseplate of an IGBT power module. The nucleate pool boiling curve can be subdivided in three zones. At low heat fluxes (lower than 20 kW/m
²
), partial nucleate boiling occurs. This zone is followed by fully developed nucleate boiling, between 20 kW/m
²
and 90 kW/m
²
, with a significantly steeper slope of the boiling curve. At even higher heat fluxes, between 90 kW/m
²
and the critical heat flux, the partial dryout zone results in a decrease of the slope of the boiling curve. A single power-max relation is not appropriate to describe this behaviour, although it is found in the most-used correlations for nucleate pool boiling heat transfer. This work proposes a combination of three power-law relations to fit the measurement data, one for each of the three nucleate pool boiling zones.