Showing papers by "Anthony M. Jacobi published in 2023"
TL;DR: In this paper , the authors demonstrate two independent highly scalable and cost-effective methods to generate micro- and nanostructures on copper and stainless steel, two widely used metals in energy and thermal applications.
Abstract: Incorporation of micro- and nanostructures on metals can improve thermal performance in a variety of applications. In this work, we demonstrate two independent highly scalable and cost-effective methods to generate micro- and nanostructures on copper and stainless steel, two widely used metals in energy and thermal applications. The performance of the developed structures, fabricated using scalable chemical etching techniques, is compared against their respective base metals. Our results demonstrate significant flow boiling heat transfer coefficient improvements up to 89% for etched copper and 104% for etched stainless steel. Mercury porosimetry is used to demonstrate that the varying pore-size distributions and presence of micro/nanoscale channels help to regulate heat transfer mechanisms, such as nucleate and convective flow boiling. Furthermore, structure integrity after 7-day flow boiling tests demonstrate surface structure resiliency to damage, a key challenge to implementation. This work combines advances in thermal performance with surface structure durability to provide guidelines for broader application of similar chemical etching methods to scalably create micro- and nanosculptured surfaces.
3 citations
TL;DR: In this article , a fabrication method to generate interal microstructures in 5.2 mm internal diameter finned aluminum tubing through crystallographic chemical etching to further increase heat transfer coefficients of low-GWP refrigerant R-515B was demonstrated.
01 Jan 2023
TL;DR: In this paper , the authors explore vortex shedding and boundary-layer re-starting effects on heat exchanger performance using data from offset-strip and louvered fins, and find that the shedding structure in irregular arrays vitiates the expected heat transfer impact.
Abstract: Data from offset-strip and louvered fins are used to explore vortex shedding and boundary-layer re-starting effects on heat exchanger performance. Both mechanisms are important to offset-strips, but only boundary-layer effects are important to louvers. The shedding structure in irregular arrays vitiates the expected heat transfer impact. Unless the effects of array regularity on vortex structure are understood, strategies for enhancing offset-strip fin arrays should focus on shedding, and louver enhancements should exploit boundary-layer thinning.
TL;DR: In this article , micro-and nanostructured surfaces are applied to the internal wetted areas of copper and aluminum mini-channels to enhance the condensation heat transfer coefficient of hydrofluorocarbon R1233zd(E) refrigerant.