化工学报
化工學報
화공학보
CIESC Jorunal
2015年
11期
4350-4358
,共9页
微通道%气液两相流%流型%相分布%液膜%液滴份额
微通道%氣液兩相流%流型%相分佈%液膜%液滴份額
미통도%기액량상류%류형%상분포%액막%액적빈액
microchannels%gas-liquid flow%flow patterns%phase distribution%film%share of entrained liquid droplets
以空气、去离子水为实验工质,在θ=50°的Y型混合器内充分混合,利用高速摄像仪对当量直径177.8μm的小曲率蛇形微通道进行可视化实验,对比了两种气液混合方式(上气下液型、上液下气型)下的流动特性。实验发现的主要流型有弹状流、波状分层流、弥散流等,对此分别研究了气弹的形状和长度、液膜厚度以及气流携带液滴的份额,并提出新的预测液滴含量的关联式。此外,针对这两种不同的混合方式,在弯道处发现圆弧可以诱导产生弹状流,二者均经历拉伸和断裂过程,区别在于后者在拉伸之前,先要进行膨胀。不同的气液混合方式对各相的流动会产生一定的影响,两相流体在通道壁面附近以及弯道处的分布也有所区别。
以空氣、去離子水為實驗工質,在θ=50°的Y型混閤器內充分混閤,利用高速攝像儀對噹量直徑177.8μm的小麯率蛇形微通道進行可視化實驗,對比瞭兩種氣液混閤方式(上氣下液型、上液下氣型)下的流動特性。實驗髮現的主要流型有彈狀流、波狀分層流、瀰散流等,對此分彆研究瞭氣彈的形狀和長度、液膜厚度以及氣流攜帶液滴的份額,併提齣新的預測液滴含量的關聯式。此外,針對這兩種不同的混閤方式,在彎道處髮現圓弧可以誘導產生彈狀流,二者均經歷拉伸和斷裂過程,區彆在于後者在拉伸之前,先要進行膨脹。不同的氣液混閤方式對各相的流動會產生一定的影響,兩相流體在通道壁麵附近以及彎道處的分佈也有所區彆。
이공기、거리자수위실험공질,재θ=50°적Y형혼합기내충분혼합,이용고속섭상의대당량직경177.8μm적소곡솔사형미통도진행가시화실험,대비료량충기액혼합방식(상기하액형、상액하기형)하적류동특성。실험발현적주요류형유탄상류、파상분층류、미산류등,대차분별연구료기탄적형상화장도、액막후도이급기류휴대액적적빈액,병제출신적예측액적함량적관련식。차외,침대저량충불동적혼합방식,재만도처발현원호가이유도산생탄상류,이자균경력랍신화단렬과정,구별재우후자재랍신지전,선요진행팽창。불동적기액혼합방식대각상적류동회산생일정적영향,량상류체재통도벽면부근이급만도처적분포야유소구별。
In this work, visualization experiments were carried out in serpentine microchannels with Y-type microfluidic junction and small curvature using a high-speed camera. Visible rectangular microchannels with the equivalent diameter of the 177.8μm were fabricated using transparent glass and polydimethylsiloxane (PDMS). Air and deionized water were well mixed in the Y-type mixer. First, gas and liquid were injected into inlets 1 and 2, respectively. And then, the order would be reversed. Flow characteristics of these two different mixing modes were compared. The main flow patterns such as slug flow, wavy stratified flow and dispersed flow were observed. In this regard, the shape and length of slug, thickness of liquid film and share of liquid droplets entrained by gas phase were investigated in succession, and a new correlation to predict droplets content was proposed based on the measured data. In addition, the arc at the corner can induce slug flow for these two different ways of mixing. Both of them were experiencing tension and fracture processes. The difference was that the latter would like to carry out expansion firstly due to the obstruction by the liquid. The gas-liquid mixture in different ways could have some impact on the flow of each phase and the distribution of two phases near the wall or in the bends was also different.