In fully-developed pressure-driven flow, the spreading of a dissolved solute is enhanced in the flow direction due to transverse velocity variations in a phenomenon now commonly referred to as Taylor–Aris dispersion. It is well understood that the characteristics of the dispersion are sensitive to the channel’s cross-sectional geometry. Here we demonstrate a method for manipulation of dispersion in a single rectangular microchannel via controlled deformation of its upper wall. Using a rapidly prototyped multi-layer microchip, the channel wall is deformed by a controlled pressure source allowing us to characterize the dependence of the dispersion on the deflection of the channel wall and overall channel aspect ratio. For a given channel aspect ratio, an optimal deformation to minimize dispersion is found, consistent with prior numerical and theoretical predictions. Our experimental measurements are also compared directly to numerical predictions using an idealized geometry.

在充分发展的压力驱动流中，由于横向速度的变化（现在通常称为泰勒-阿里斯色散），溶解的溶质在流动方向上的扩散得以增强。众所周知，分散体的特性对通道的横截面几何形状敏感。在这里，我们演示了一种通过控制其上壁的变形来控制单个矩形微通道中的分散的方法。使用快速原型化的多层微芯片，通道壁在受控压力源的作用下变形，从而使我们能够表征色散对通道壁挠度和总通道纵横比的依赖性。对于给定的通道长宽比，找到了使色散最小的最佳变形，与先前的数值和理论预测一致。我们的实验测量结果也直接与使用理想几何形状的数值预测进行了比较。