Two-phase cooling systems, power electronics modules, and methods for extending maximum heat flux

#The present specification generally relates to two-phase cooling devices and systems and, more particularly, to two-phase cooling systems, power electronics modules, and methods for extending a maximum heat flux point of a two-phase cooling device.

#Heat generating devices, such as power semiconductor devices, may be coupled to a heat spreader to remove heat and lower the maximum operating temperature of the heat generating device. In some applications, coolant fluid may be used to receive heat generated by the heat generating device by convective thermal transfer, and remove such heat from the heat generating device. For example, jet impingement may be used to cool a heat generating device by directing impingement jets of coolant fluid onto the heat generating device or onto a target surface that is thermally coupled to the heat generating device.

#Two-phase cooling may also be utilized, where the heat generating device is cooled by the phase change of the coolant fluid from a liquid to a vapor. In two-phase cooling, the transfer of heat from the device surface to the coolant fluid takes place via bubble generation from boiling. The use of the boiling phenomena to dissipate high heat fluxes (W/cm2) from surfaces is an effective mode of heat transfer. Every surface has a representative boiling curve that ranges from low heat flux (single phase) to maximum heat flux (i.e., safe heat flux) for a given fluid inlet temperature of a coolant fluid. Beyond the maximum heat flux value, all of the liquid coolant fluid transforms to vapor and may result in failure of the device that is attached to the two-phase cooling device.

#The embodiments set forth in the drawings are illustrative and exemplary in nature and not intended to limit the subject matter defined by the claims. The following detailed description of the illustrative embodiments can be understood when read in conjunction with the following drawings, where like structure is indicated with like reference numerals and in which:

#FIG. 1 schematically depicts a cross sectional view of a jet impingement, two-phase cooling device according to one or more embodiments described and illustrated herein;

#FIG. 2 schematically depicts a cross sectional view of a two-phase cooling apparatus according to one or more embodiments described and illustrated herein;

#Embodiments of the present disclosure are directed to two-phase cooling systems, power electronics modules and methods for operating a two-phase cooling device wherein a maximum heat flux point (i.e., the critical heat flux) is increased by lowering a temperature of an inlet fluid. More specifically, embodiments described herein extend the maximum heat flux for a given surface by dynamically changing the inlet temperature of the coolant fluid. As the two-phase cooling device operates at or close to a maximum heat flux point, the temperature of the coolant fluid at the inlet of the two-phase cooling device is lowered to raise the maximum heat flux point of the particular surface and coolant fluid (i.e., extend the maximum heat flux point on a boiling curve of the coolant fluid with respect to the surface).

#Various embodiments of two-phase cooling systems, power electronics devices and methods for extending a maximum heat flux point are described in detail below.

#The two-phase cooling devices of the present disclosure may include jet impingement cooling devices, or pool boiling, two-phase cooling devices that do not incorporate jet impingement. FIG. 1 schematically depicts an example jet impingement, two-phase cooling device 10 in cross section, while FIG. 2 schematically depicts an example two-phase cooling device 10′ that does not utilize jet impingement. The embodiments depicted by FIGS. 1 and 2 are for illustrative purposes only. It should be understood that the dynamic control of the temperature of inlet coolant fluid described herein may be incorporated into any two-phase cooling device.