十字型微通道中非定常分散相速度下液滴生成的数值分析  被引量:6

Numerical Simulation of Droplet Generation in Cross-Junction Microchannel under Changing Dispersion Phase Velocities

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作  者:陈珉芮 钱锦远[1,2] 李晓娟 金志江 CHEN Min-rui;QIAN Jin-yuan;LI Xiao-juan;JIN Zhi-jiang(Institute of Process Equipment,Zhejiang University,Hangzhou 310027,China;Department of Energy Sciences,Lund University,Lund 22100,Sweden)

机构地区:[1]浙江大学化工机械研究所,杭州310027 [2]瑞典隆德大学能源科学系,瑞典隆德22100

出  处:《高校化学工程学报》2018年第3期522-528,共7页Journal of Chemical Engineering of Chinese Universities

基  金:浙江省自然科学基金重点项目(LZ17E050002);浙江省重点科技创新团队项目(2011R50005)

摘  要:微液滴因其独特的流体力学特性和尺寸效应,在许多领域得到了广泛的应用。在制备微液滴时常使用蠕动泵为流体提供流动推动力。实际上,当时间尺度足够小时,蠕动泵提供的推动力是呈一定周期性变化的,这对液滴的生成来说是一种周期性的扰动。为研究周期性扰动对十字型微通道内液滴生成的影响,本文基于经过验证的模型,在分散相入口流速为时间的正弦函数条件下对液滴生成情况进行了数值模拟。模拟采用流体体积(VOF)模型,以硅油为连续相、水为分散相,首先模拟了两相流体入口流速均为0.01 m×s^(-1)的工况,得到液滴生成时间为0.08 s。导入周期分别为0.04、0.08、0.12、0.16 s以及振幅分别为0.0025、0.005、0.0075、0.01的正弦函数作为分散相入口流速,模拟不同条件下液滴的尺寸和生成时间。模拟结果表明,当正弦函数周期≤0.08 s时,改变周期和振幅对液滴尺寸和生成时间的影响较小;当正弦函数周期大于0.08 s时,液滴尺寸和生成时间会呈现周期性变化。而正弦函数的振幅对液滴的生成影响不明显,只对液滴生成达到稳定状态的时间有影响。Micro-droplets with excellent physical properties and size effects are widely used in different fields. Peristaltic pumps are often used for droplet generation. The thrust force of pumps is periodic as a periodic disturbance when the time scale is short enough. Numerical simulation based on a validated model was applied to study the periodic disturbance effects on droplet generation in a cross-junction microchannel. A volume of fluid(VOF) method was adopted with the continuous phase of silicon oil and the disperse phase of water. When the velocity of the continuous and dispersed phases is both 0.01 m×s^(-1), the droplet generation time is 0.08 s. Sine functions with cycles of 0.04, 0.08, 0.12 and 0.16 s and amplitudes of 0.0025, 0.005, 0.0075 and0.01 were imported as the inlet velocity of the disperse phase. Droplet sizes and generation times were obtained by simulating different flow processes. The results show that when the cycle is less than 0.08 s, changes of cycle time and amplitude have few effects on droplet size and generation time. However, when the cycle time is larger than 0.08 s, droplet size and generation time change periodically. Furthermore, amplitude has few effects on droplet generation

关 键 词:微通道 两相流 微液滴 入口流速 流体体积模型 

分 类 号:TQ021.1[化学工程]

 

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