摘要
自循环微气体发生器因其无寄生功耗的特色而引发关注.揭示气泡运动机理能为高效自循环微气体发生器的微通道优化设计提供科学依据,本文以流体动力学为基础,对自循环微通道气体发生器中气泡运动进行数值模拟,探究虚拟阀微通道高度比h,壁面接触角θ_(t),疏水层接触角θf对气泡运动的影响.从中发现:(1)在无疏水层的通道中,当h≥3,0<cosθ_(t)≤0.5时,气泡的运动时间可用1/Δp进行预测,而其他工况因漩涡位置,数量的变化,增大了能量的耗散,使得气泡运动时间缩短速率变缓,脱离理论预测.(2)在无疏水层的通道中,气泡的运动时间随着微通道高度比的增加而逐渐减少.当高度比h≥5时,气泡运动时间的变化趋于平稳.而且,气泡运动时间随着cosθ_(t)的增加也呈现出减少的趋势,并且当θ_(t)≤45°时,减少趋势显著变缓.值得注意的是,θ_(t)相对于h,对气泡运动时间的影响表现出更高的敏感性.(3)在主通道中加入疏水层时,由于接触角的转变,气泡界面产生阻尼振荡运动,随着|cosθ_f|的增大,阻尼振荡运动振幅增大,导致能量消耗变大,以致理论不足以预测气泡运动时间.且气泡运动时间随着|cosθ_f|的增大而减少,大小则呈线性关系.
Self-circulating microchannel gas generators have garnered significant attention owing to their zero parasitic power consumption.Elucidating the bubble dynamics mechanism is critical for optimizing microchannel design in high-efficiency gas generators.In this study,a numerical simulation of bubble motion in self-circulating micro gas generators was conducted using Ansys Workbench,based on fluid dynamics principles.The effects of key parameters,i.e.,microchannel height ratio h,wall contact angleθ_(t),and hydrophobic layer contact angleθf were systematically investigated.The results demonstrate that:(1)In hydrophobic layer-free channels,when h≥3 and 0<cosθ_(t)≤0.5,the bubble transit time can be accurately predicted by 1/Δp.In other cases,shifts in vortex positions and quantities enhance energy dissipation,causing the bubble transit time reduction rate to decelerate and deviate from theoretical predictions.(2)For channels without hydrophobic layers,the bubble transit time decreases monotonically with increasing h.This trend stabilizes when h≥5.Additionally,the transit time decreases with higher cosθ_(t),though the rate of decrease diminishes significantly whenθ_(t)≤45°.Notably,θ_(t) exhibits greater sensitivity to transit time compared to h.(3)Introducing a hydrophobic layer in the main channel triggers damping oscillations at the bubble interface due to abrupt contact angle transitions.Larger|c o sθf|values amplify oscillation amplitudes,thereby increasing energy dissipation and invalidating theoretical time predictions.Furthermore,the transit time decreases linearly with increasing|c o sθf|.
作者
莫成龙
产文强
陈柔
严微微
MO Chenglong;CHAN Wenqiang;CHEN Rou;YAN Weiwei(College of Metrology&Measurement Engineering,China Jiliang University,Hangzhou 310018,Zhejiang,China;College of Energy Environment&Safety Engineering,China Jiliang University,Hangzhou 310018,Zhejiang,China)
出处
《力学季刊》
北大核心
2025年第2期498-508,共11页
Chinese Quarterly of Mechanics
基金
国家自然科学基金(12102419)
浙江省自然科学基金(Z24A020005)。
关键词
自循环
高度比
虚拟阀
接触角
疏水层
self-circulation
height ratio
virtual valve
contact angle
hydrophobic layer
