CAJ | 학술논문

流体在微米级通道中的流动规律与常规通道不同,其区别主要体现在摩擦因子、转捩雷诺数和泊肃叶数等方面。针对上述问题,实验研究了水在水力直径为167~195 m矩形硅通道和水力直径为168~399 m圆形玻璃微管中的流动特性。结果表明,对水力直径为167~195 m的矩形通道,其转捩雷诺数发生在1 300~1 480;对水力直径为168~399 m的圆形通道,其转捩雷诺数位于2 600~2850,且二者的摩擦因子和泊肃叶数与理论值基本一致,这说明了微通道的形状对流动阻力特性没有明显影响。通道S-3的长径比为173,其入口段长度比常规管道入口段略长,说明微通道的入口效应较明显。实验测量了微通道的局部阻力压降随流量变化的关系。结果表明,突变微通道内水流动的局部阻力符合常规理论曲线。
류체재미미급통도중적류동규률여상규통도불동,기구별주요체현재마찰인자、전렬뢰낙수화박숙협수등방면。침대상술문제,실험연구료수재수력직경위167~195 m구형규통도화수력직경위168~399 m원형파리미관중적류동특성。결과표명,대수력직경위167~195 m적구형통도,기전렬뢰낙수발생재1 300~1 480;대수력직경위168~399 m적원형통도,기전렬뢰낙수위우2 600~2850,차이자적마찰인자화박숙협수여이론치기본일치,저설명료미통도적형상대류동조력특성몰유명현영향。통도S-3적장경비위173,기입구단장도비상규관도입구단략장,설명미통도적입구효응교명현。실험측량료미통도적국부조력압강수류량변화적관계。결과표명,돌변미통도내수류동적국부조력부합상규이론곡선。
Flow characteristics in channels with micron dimension are different from macroscale channels,which mainly embodies three aspects friction factor,transition Reynolds number and Poiseuille number.With this background,the flow characteristics of water were experimentally investigated in rectangular silicon microchannels with hydrodynamic diameter ranging from 167 m to 195 μm and 168 m to 399 m for circular glass microtubes.The experimental results show that the values of the critical Reynolds number fall between 1 300 and 1 480 in rectangular microchannels with the hydrodynamic diameter of 167 m to 195 m while falling between 2 600 and 2 850 in circular microtubes with the hydrodynamic diameter of 168 m to 399 m;Besides,the friction factor and Poiseuille number of both rectangular microchannels and circular microtubes are consistent with the theoretical values,which indicates geometric features have no significant influence on flow resistance.The entrance length in channel S-3 with length-diameter ratio of 173 is slightly more than that of conventional channel,which shows that the entrance effect is obvious in micro-scale channel.Investigation of the relationship of local resistance versus the flow rate in rectangular silicon microchannel shows good agreement between theoretical curves and experimental results.