机械工程学报
機械工程學報
궤계공정학보
CHINESE JOURNAL OF MECHANICAL ENGINEERING
2015年
14期
160-166
,共7页
颗粒惯性聚集%弹性颗粒%惯性升力%附加升力%惯性微流
顆粒慣性聚集%彈性顆粒%慣性升力%附加升力%慣性微流
과립관성취집%탄성과립%관성승력%부가승력%관성미류
inertial focus of particles%elastic particle%inertial lift%extra lift%inertial microfluidics
建立一个简单模型以描述球状颗粒弹性变形特征，并根据“运动相对性原理”，提出一种描述弹性颗粒准定常运动的数值计算方法，据此研究在方形截面微通道层流场中，弹性球状颗粒所受惯性升力的空间分布特征，揭示了颗粒的弹性变形对惯性升力的影响特点。研究结果表明：弹性颗粒在低Re数通道内运动时，仍存在稳定的横向聚集位置。与对应刚性颗粒相比，弹性颗粒的聚集位置更靠近通道中心，且随颗粒弹性的增加，其聚集位置会向通道中心偏移；弹性颗粒所受惯性升力的空间分布特征与刚性颗粒相似，但颗粒弹性变形会额外产生一个附加升力。这个附加升力的方向始终指向通道中心且随弹性颗粒变形幅度的增加而增大；弹性颗粒所受的惯性升力由“切应力分量”与“压力分量”构成，然而后者是诱发弹性颗粒产生惯性聚集运动的力学成因。
建立一箇簡單模型以描述毬狀顆粒彈性變形特徵，併根據“運動相對性原理”，提齣一種描述彈性顆粒準定常運動的數值計算方法，據此研究在方形截麵微通道層流場中，彈性毬狀顆粒所受慣性升力的空間分佈特徵，揭示瞭顆粒的彈性變形對慣性升力的影響特點。研究結果錶明：彈性顆粒在低Re數通道內運動時，仍存在穩定的橫嚮聚集位置。與對應剛性顆粒相比，彈性顆粒的聚集位置更靠近通道中心，且隨顆粒彈性的增加，其聚集位置會嚮通道中心偏移；彈性顆粒所受慣性升力的空間分佈特徵與剛性顆粒相似，但顆粒彈性變形會額外產生一箇附加升力。這箇附加升力的方嚮始終指嚮通道中心且隨彈性顆粒變形幅度的增加而增大；彈性顆粒所受的慣性升力由“切應力分量”與“壓力分量”構成，然而後者是誘髮彈性顆粒產生慣性聚集運動的力學成因。
건립일개간단모형이묘술구상과립탄성변형특정，병근거“운동상대성원리”，제출일충묘술탄성과립준정상운동적수치계산방법，거차연구재방형절면미통도층류장중，탄성구상과립소수관성승력적공간분포특정，게시료과립적탄성변형대관성승력적영향특점。연구결과표명：탄성과립재저Re수통도내운동시，잉존재은정적횡향취집위치。여대응강성과립상비，탄성과립적취집위치경고근통도중심，차수과립탄성적증가，기취집위치회향통도중심편이；탄성과립소수관성승력적공간분포특정여강성과립상사，단과립탄성변형회액외산생일개부가승력。저개부가승력적방향시종지향통도중심차수탄성과립변형폭도적증가이증대；탄성과립소수적관성승력유“절응력분량”여“압력분량”구성，연이후자시유발탄성과립산생관성취집운동적역학성인。
A simple model is presented to describe the elastic deformation of a spherical particle, by which a numerical approach is proposed to describe the quasi-stationary motion of an elastic particle translating in the laminar flow of a squared micro-channel based on the ‘Motion Relativity’. The behavior of the inertial lift exerted on an elastic particle is numerically investigated and the emphasis of this study is to reveal the influence on the inertial lift by the deformation of the elastic particle. Results indicate that there is always a transverse focused position for an elastic particle translating in a laminar micro-channel flow with low Reynolds number. The focused position of an elastic particle may shift closer to the centerline of the channel than that of a rigid particle, with the increased deformation of the elastic particle. The behavior of the inertial lift exerted on an elastic particle is similar with that exerted on a rigid particle but there is an extra lift exerted on an elastic particle, resulted by the deformation. This extra lift is always towards to the centerline of the channel and its magnitude may increase with the increased deformation of the elastic particle. The inertial lift can be divided into a “viscous component” and a “pressure component” while the latter is a critical formation mechanism for the inertial focus of elastic particles.
