| 1 | Effect of geometrical configurations on alkaline air-breathing membraneless microfluidic fuel cells with cylinder anodes显示文摘Membraneless microfluidic fuel cells(MMFCs) outperform traditional membrane-based micro-fuel cells in membraneless architecture and high surface-to-volume ratio and facile integration, but still need substantial improvement in performance. The fundamental challenges are dictated by multiphysics regarding cell configurations: the interaction of fluid flow, mass transport and electrochemical reactions. We present a numerical research that investigates the effect of geometrical configurations(rod arrangement, cell length, rod diameter and spacer configuration) on the fuel transport and performance of an alkaline MMFC with cylinder anodes. Modeling results suggest that the staggered rod arrangement outperforms the in-line case by 10.1% at 50 μL min^(–1). Cell power output and power density vary nearly linearly with the cell length. In the case with 0.7 mm anodes and 0.3 mm spacers, the increased flow resistance at anode region drives the fuel to intrude into the spacer zone, leading to fuel transport limitation at downstream. The feasibility of non-spacer configuration is demonstrated, and the power density is 93.7% higher than the baseline due to reduced cell volume and enhanced fuel transport. In addition, horizontal extension of the anode array is found to be more favorable for scale-up, the maximum power density of 181.9 mW cm^(–3) is predicted. This study provides insight into the fundamental, and offers guidance to improve the cell design for promoting performance and facilitating system integration. | ZHANG Biao WANG HaoNan ZHU Xun YE DingDing LIAO Qiang SUI PangChieh DJILALI Ned JIANG Li FU YaLu | 2019 | Science China(Technological Sciences)2019，62，3： | 0 |
| 2 | Predicting near-wall turbulence with minimal flow units in compressible turbulent channel flows显示文摘Mach number effects on the near-wall turbulence in the absence of outer motions remain unclear so far.The present study extends the Minimal Flow Units(MFUs),a widely applied method to investigate near-wall turbulence free from the impact of large-scale motions in the outer region in incompressible channel flows,to compressible wall-bounded turbulence.The compressible near-wall turbulence in MFU proves accurate in replicating near-wall statistics,independent of Mach number and statistically equivalent to the universal signals extracted from the full-sized channel.It is further utilized as universal signals in the predictive models of compressible near-wall turbulence,which is capable of accurately predicting variances and joint probability density functions of velocity and temperature fluctuations. | Ming YU Yalu FU Zhigong TANG Xianxu YUAN Chunxiao XU | 2023 | Chinese Journal of Aeronautics2023，36，8： | 0 |
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