A pressure drop investigation of immiscible liquid-liquid micro flows

Abstract

Over the past decade there has been a considerable increase in the research on lab-on-a-chip applications that focuses on designing analytical chemical and biological devices. One such application is the possibility of integrating the functional steps of DNA analysis into a micro-total-analysis system (μTAS). Encapsulation of PCR samples within an inert carrier fluid allows the samples to be transported as micro-reactors. Plug based micro reactors suspended in an inert carrier fluid have a lot of promise in microfluidic analytical devices, offering a reduction in resident-time, reagents and labour with an increase in through-put, accuracy and quality. The development of a thin wetting film between the wall of the capillary and the micro reactor increase the interfacial area of the plug and can also intensify the internal circulation occurring within the plug. Only recently has work being preformed on the fluid mechanics that characterise this scale. An experimental study is carried out to study the effect capillary diameter, carrier viscosity and flow rate has on the pressure drop under bi-phasic flow conditions.