Nondestructive and Accurate Detection of Transparent Liquid Mass Fraction Based on Snell's Law

Based on the Snell's law, one can convert the liquid mass fraction into the spot displacement by directing a laser into the trapezoidal component containing the solution. In this physical experiment, the trapezoidal component was designed to facilitate convenient replacement of liquids, and the CCD sensor was used to accurately record the spot position. The accurate results of liquid mass fraction was achieved by fitting sinusoidal-cubic functions after theoretical modification. In this study, the refractive index of the measured solution ranges from 1.333-1.414, with an actual resolution of approximately 0.0003. The mass fraction resolution accuracy is roughly ±0.2% for sodium chloride, sucrose, and D-glucose while it is ±0.4% for ethanol solution. This resolution has increased in comparison to similar physical principle experiments, and it can now successfully fulfill the daily detection criteria for the transparent liquid mass fraction.