Microfluidics technology has grown rapidly over the past decades due to its high surface-to-volume ratios, flow controllability, and length scales efficiently suited for interacting with microscopic elements. These properties have proven to be well-suited to biology and chemistry, in which localized precision is usually an advantage. However, as a consequence of the small rates of mixing and transfer they achieve due to operating under laminar (smooth) flow regimes, the utilization of microfluidics for energy applications has long been a key challenge. In this regard, as a result of the thermophysical properties they exhibit in the vicinity of the pseudo-boiling region, it has been recently proposed that microconfined turbulence could be achieved by operating at high-pressure transcritical fluid conditions. However, the underlying flow mechanisms of such systems are still not well characterized and thus need to be carefully investigated. Consequently, this work analyzes supercritical microconfined turbulence by computing direct numerical simulations of high-pressure (P/Pc = 2) N2 at transcritical temperature conditions imposed by a temperature difference between the bottom (T /Tc = 0.75) and top (T /Tc = 1.5) walls for a friction Reynolds number of Ret = 100 (bottom wall). The results obtained indicate that microconfined turbulence can be achieved under such conditions, leading to transfer increments up to 20× those that occur in equivalent low-pressure configurations.

Technical report