Design and Evaluation of Viscosity Measurement Device Based on Capacitance Method

This article describes the design and evaluation of a capillary measurement device based on the capacitance method that accurately measures fluid viscosity. The device includes signal detection and processing, and the data acquisition module. The experimental device is calibrated with a standard fluid to further investigate the device’s performance. The calibration result was compared with both the NIST and literature values, with an average relative deviation (ARD) of 1.30%. Based on this, the expanded uncertainty is obtained to be within 2.40% by assessing all impact factors affecting viscosity measurement. The experimental device is evaluated by repeatability, sensitivity, and minimum detectable amount to prove the reliability of the device further. The repeatability, the sensitivity, and the minimum detectable amount of the device are 0.15%, 2.6894 F, and 0.1487 mV/F, respectively. By comparing with other viscosity measurement methods, further elucidate the outstanding advantages of this device. In addition, the viscosities of pure esters, alcohols, and their mixtures were measured and compared with literature values, resulting in an ARD of 1.96%. Furthermore, the universal applicability and stability of the device were confirmed by analyzing the specific deviations of both individual elements and mixtures.