THE CAPABILITY OF THE VISCOSITY MEASUREMENT PROCESS

Abstract

The aim of the paper is to evaluate the quality of measurement process of the dynamic viscosity using the Measurement Systems Analysis and the analysis of uncertainty. The viscosity of a fluid is defined as a measure of its resistance to gradual deformation by shear stress or tensile stress. Viscosity is a property arising from collisions between neighboring particles in a fluid that are moving at different velocities. Dynamic or absolute viscosity is a measure of the internal resistance of the fluid. The measurement process is realized which of ten samples of vegetable and mineral oils, four operators and the viscometer ―Rheotest-2‖. The temperature of individual oil was according to customer requirement. The process of the measurement according to the Measurement Systems Analysis is capable because the value of index %GRR is 8.85 %. Operators do not have a statistically significant effect on the measured viscosity or its uncertainty. The paper presents a procedure to calculate the uncertainty of the measured values of dynamic viscosity. In addition to possible sources of uncertainty that are reported in the available literature, the calculation is supplemented by further sources, also important according to authors.