Immersion Cooling of Electronics Utilizing Lotus-Type Porous Copper

Abstract

This paper evaluates boiling heat transfer performance on a lotus-type porous copper plate attached onto a heated surface. The experiments are performed under atmospheric and saturated pool conditions. The lotus copper plates have uni-directional pore structure in a perpendicular direction for the heated surface and the average hydraulic diameter of the pore hole is 0.36 mm. The lotus copper plate of 1.0 mm or 2.0 mm in thickness is mechanically attached or soldered onto the heated surface in order to obtain the referential boiling heat transfer data of utilizing the lotus copper plate. The boiling curves suggest that the utilization of the lotus copper plate leads to boiling heat transfer enhancement especially in a low heat flux regime even when the lotus copper is mechanically attached to the heat transfer surface. However, the thickness of the lotus plate doesn’t affect the boiling heat transfer in the mechanically attached case, which indicates that there is a big contact thermal resistance between the heated surface and the lotus copper plate. In addition, it is confirmed that the critical heat flux in the mechanically attached case is almost the same as that in the smooth surface case. On the other hand, the critical heat flux increases up to 216 W/cm2 by soldering the lotus copper plate to the heated surface, which is almost double of that in the smooth surface case.