Design and testing of portable laser-based viscometer

Abstract

Viscosity is one of a physical parameter of a fluid. Viscosity shows a coefficient of resistance in the fluid to reduce the speed of the fluid in a system. In the present study, design and testing has been carried out on a portable laser-based viscometer with the falling sphere method. The main mechanical system consists of two components: an acrylic tube with an inner diameter of 2.335 cm with a length of 28 cm, and a glass sphere diameter of 11.58 mm with the density of 2521 kgm-3. Two lasers with a wavelength of 650 nm are used to determine the traveling time of a sphere in a range of 11 cm in the sample. Two photodiodes are used to capture the light signal and then forwarded it to the Arduino Uno R3 microcontroller to calculate the falling velocity of the sphere and the viscosity of the sample then displayed into a LCD (2×16). Reproducibility of the viscosity measurement data was confirmed with the standard deviation varied from 0.08 to 1.9 mPas. The sensitivity and the precision of the present design increased with the viscosity value.