Evaluation of a falling sinker-type viscometer for the measurement of olive oil viscosity at high pressure

In this work we evaluate the performance of a high pressure falling body type viscometer. This type of viscometer is used to determine the viscosity of liquids up to 500 MPa and has direct application in the food industry which is increasingly using high pressure to process certain foods. By ensuring laminar flow between the descending sinker under the influence of gravity and the tube wall, an analytical solution to flow can be determined. However, a calibration fluid with a known viscosity profile under high pressure is required to correct the determined viscosity data. In view of the discrepancies, we have examined the flow profile of the oil and sinker during operation through the use of a computational fluid dynamic simulation. We have been able to confirm the presence of complex flow patterns which influence considerably the rate of sinker descent and thus viscosity data.