S055013 テイラー・ディーン流れを利用したマイクロミキサ : 流路の回転効果([S055-01]内部流れ(1))

Abstract

The micromixer, which has a rotor with a curved channel, is studied experimentally. The Taylor-Dean flow in a curved channel of rectangular cross-section is investigated using PIV (Particle Image Velocimetry) and LIF (Laser Induced Fluorescence) methods. Two walls of the channel (the inner and top walls) rotate around the center of curvature and a pressure gradient is imposed in the direction of the exit of the channel. The non-dimensional channel curvature δ=α/R is taken to be about 0.1, where 2α is the width of the channel, R the curvature radius of the channel. Other non-dimensional parameters concerned are the Dean number De=Reδ^<1/2>, where Re=qd_h/v is the Reynolds number, q the mean flow velocity in the channel axis direction, d_h the hydraulic diameter of the channel, v the kinematic viscosity, and the Taylor number Tr=2α^2Ω(2δ)^<1/2>/(δv), where Ω is the angular velocity of the rotor. Photographs of the flow in a cross-section at 180° downstream from the curved channel entrance are taken by changing the flux (De) at a constant rotational speed (Tr) of the channel walls. It is found that good mixing performance is obtained in the case of De %le; 0.1|Tr|. This tendency appears more strongly if aspect ratio is large. And then we have confirmed the occurrence of reversal of the mean axial flow.