用于微流体驱动用的微型文氏管的结构优化

Optimum Design of the Micro-Venturi for Microfluidic Driving

为了给组织液的透皮抽取提供负压值,本文研究了结构简单、加工方便的PDMS微型文氏管的优化设计.首先理论推导了文氏管的结构参数对输出负压的影响规律,然后采用Fluent进行模拟计算,接着用模塑法设计加工了PDMS文氏管,并搭建了文氏管输出负压的检测系统,最后对实验结果进行分析讨论.通过对比测量,给出了适用于本文的微型化文氏管结构,即喉管长×宽×高为6 mm×0.25 mm×0.25 mm、收缩角30°、扩散角30°.本文设计加工的文氏管在220 kPa的正压下可输出87 kPa的负压,提高了组织液透皮抽取的效率.该微型文氏管同以往的真空发生装置相比既能满足系统小型化和集成化要求,又能在相对较小的输入压强下,为组织液透皮抽取提供足够高的真空负压输出,为驱动微管路内流体输运提供足够大的抽取速率.

In order to provide negative pressure for the interstitial fluid （ISF） transdermal extraction, an optimized micro-Venturi tube fabricated with polydimethylsiloxane （PDMS） which has a simple structure and is easy to process was studied in this paper. First the impact of the structural parameters on the out- put vacuum of the Venturi tube was theoretically analyzed, then simulation was carried out using Fluent and the Venturi tube was processed through molding, the detection system for the output vacuum of the Venturi tube was set up, and finally the experimental results were analyzed and discussed. By comparing the measurement results, the miniaturized structure of Venturi tube appropriate for this paper was presen- ted with the length, width and height of vena contracta section being 6 mm× 0. 25 mm×0. 25 mm, the convergence angle 30° and the divergence angle 30°. The designed and processed Venturi tube can out- put the vacuum of 87 kPa under the input pressure of 220 kPa, which will enhance the efficiency of ISF transdermal extraction. This micro-Venturi tube satisfies the requirements of miniaturization and integra- tion as compared with the conventional vacuum generating, and can provide a sufficiently high vacuum output for ISF transdermal extraction at a relatively small input pressure.