Spray cooling for the 3-D cube computer

The results of an experimental investigation into high performance thermal management for an advanced 3-D computer are presented. Chips are mounted on synthetic diamond substrates. The substrates are then stacked and integrated with vertical vias. Two faces of the resulting “cube” computer are reserved for clamping the structure together, two are reserved for power insertion and signal I/O, and the remaining two faces are spray cooled. The heat generated by the chips is conducted laterally out to the cube faces in the high thermal conductivity diamond substrates. The edges of the substrates protrude through a seal plate into a compact spray chamber. Miniature atomizers are used to spray a dielectric coolant onto the substrate edges where the coolant vaporizes to carry away the waste heat. The vapor is condensed in an ambient heat exchanger and the liquid is recycled in a closed-loop system. Experimental results are presented for two different spray plate configurations using a stack of copper heater plates to simulate one half of the computer. Finite element analysis is used to aid in interpretation of the results and predict the junction temperatures that would result from a given spray plate configuration, computer geometry, and chip power loading. The results indicate that very high volume density heat removal is possible (15-20 kW from a four inch cube). Thus, the 3-D computer concept may be suitable for very high performance computing