微流控惠斯通电桥式通用流阻测量方法

Microfluidic Wheatstone Bridge for Measurement of Hydraulic Resistance

摘要:

标准化是微流控系统的发展趋势,很多器件需要精确的流量控制和传输。因此,准确地表征和测量芯片功能模块的流体阻力具有重要的应用价值。提出了一种类比于惠斯通电桥测量不同流阻大小的器件,该器件将一个芯片内的膜阀视为可变流阻器,与待测器件并联。通过施加不同的压力,控制膜阀的开口度,保持桥平衡,直接计算获得待测芯片的流阻大小。仿真计算发现,其测量范围达到4个数量级,误差控制在3%以内。结果表明,微流控惠斯通电桥是测量流阻的有效方法,可以根据不同的应用环境,设计不同的尺寸和结构,以满足特定需要。

Abstract:

Standardization is the trend of microfluidic system, therefore many devices require precise flow control and transport of fluid. Therefore, it’s important to characterize and measure the flow resistance for different chips. In this paper, a microfluidic analogue of the Wheatstone bridge circuit was developed for the measurement of different hydraulic resistance in a microfluidic device. It regards an on-chip membrane valve as a variable resistor, in parallel with the device. By applying different pressure, the membrane valve’s opening degree is controlled, Wheatstone bridge balance is kept, and the resistance of the chip is calculated directly. In this article, the measurement range reaching four magnitude was simulated on the computer with the error less than 3%. As a result, the microfluidic Wheatstone bridge represents an effective method for measurement of hydraulic resistance. And depending on various application environments, different dimensions and structures can be designed to satisfy special requirements.