An Experimental Study of Single-phase Heat Transfer inside an Additively Fabricated Microchannel Heat Exchanger

Effective system energy management and cooling solutions is critical for a range of increasingly complex systems and missions. Various industries and agencies seek technologies and design techniques to cool ultra-high heat fluxes in various applications, and thereby increase system energy efficiencies in future advanced lasers, radars and power electronics. There has been an increasing interest in exploiting the use of additive manufacturing in developing nontraditional cooling schemes to be built directly into components. This study investigates the heat transfer and pressure loss performance of additively manufactured micro-channel heat exchanger. A heat exchanger of 30 micron-sized channels was manufactured via the Direct Metal Laser Sintering (DMLS) method and tested at a range of Reynolds numbers. Same test setup and configurations have been used to test the DMLS manufactured micro-channel heat exchanger here, and the results are compared to the mini channel heat exchanger of similar dimension but manufactured traditionally. The results have shown that although DMLS manufactured micro-channel heat exchanger yield a higher pressure loss, it has shown significantly improved convective heat transfer compared to the mini-channel heat exchanger tested under same conditions but fabricated traditionally. It is likely that non-post processed surface of the DMLS manufactured micro-channels is the main contributor of this augmented heat transfer. Future study is needed to further understand the mechanisms behind the phenomena observed here.