Experimental and computational analysis of laser sintered three-dimensional wick structures for thermal management applications
The ability to transfer heat over long distances with a small temperature gradient is a highly coveted feature in thermal management and cooling applications for electronics. Heat pipes consisting of wick structures play a vital role in these applications since wicks provide the necessary capillary action to transport the working fluid (such as water or ammonia) from the heat source to the heat sink. The fluid absorbs heat from the source, evaporates into vapor and travels to the condenser (cooler) section of the heat pipe, where it condenses back into liquid, and gets diverted back to the evaporator section to restart the heat transfer loop. For the purposes of this work, two types of wick structures – one manufactured with copper particles and the other with stainless-steel 316L particles - are considered. Existing manufacturing capabilities pose significant barriers in terms of manufacturing time and wastes, to the creation of wick structures for efficient heat transfer. This work examines the feasibility of a novel manufacturing technique for developing microscale porous metallic structures using a pulsed microsecond carbon dioxide (CO2) laser. The preliminary results show the successful fabrication of a sintered copper powder structure at a pulse period of 1000 μs, pulse width of 180 μs. The main benefit of this new manufacturing process is that it provides a significant reduction in manufacturing time –it was observed to be approximately 4.5 hours compared to 18-24 hours in conventional sintering process that these experiments were observed against. The obtained results provide a crucial step toward developing a proof of concept for a new class of manufacturing process for porous metallic structures.
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