Affiliation:
1. Department of Fluid Mechanics, Universitat Politècnica de Catalunya·BarcelonaTech (UPC), Barcelona 08019, Spain
Abstract
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. However, as a consequence of the small rates of mixing and transfer they achieve due to operating under laminar flow regimes, the utilization of microfluidics for energy applications has long been a key challenge. In this regard, as a result of the hydrodynamic and thermophysical properties they exhibit in the vicinity of the pseudo-boiling region, it has recently been proposed that microconfined turbulence could be achieved by operating at high-pressure transcritical fluid conditions. Nonetheless, the underlying flow mechanisms of such systems are still not well characterized, and, thus, need to be carefully investigated. This work, consequently, analyzes supercritical microconfined turbulence by computing direct numerical simulations of high-pressure ([Formula: see text]) N2 at transcritical conditions imposed by a temperature difference between the bottom ([Formula: see text]) and top ([Formula: see text]) walls for a friction Reynolds number of [Formula: see text] (bottom wall). The results obtained indicate that microconfined turbulence can be achieved under such conditions, leading to mixing and heat transfer increments up to [Formula: see text] and [Formula: see text], respectively, with respect to equivalent low-pressure systems. In addition, it is found that the near-wall flow physics deviates from a single-phase boundary layer theory due to the presence of a baroclinic instability in the vicinity of the hot/top wall. This instability is generated by the combination of the external force driving the flow and the large variation of density across the pseudo-boiling region, which strongly modifies the flow behavior in the vicinity of the wall and renders present “law of the wall” transformation models inaccurate.
Funder
HORIZON EUROPE European Research Council
Formacio de Professorat Universitari - UPC
Serra Hunter
Beatriz Galindo
Subject
Condensed Matter Physics,Fluid Flow and Transfer Processes,Mechanics of Materials,Computational Mechanics,Mechanical Engineering
Cited by
8 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献