On the optimisation of a texture analyser in squeeze flow geometry

The original contribution is available at http://www.sciencedirect.com/science/article/pii/S0263224106000327International audienceThis paper describes how the range of application of a texture analyser, used for mechanical tests of solids and liquids in the food and cosmetics industry, can be extended to reproduce squeeze flow geometry. It describes the necessary optimisation of the device to ensure parallelism and thermal regulation of the plates during tests. The error on the load cell and the instrument compliance are evaluated. The influence of these artefact measurements is investigated in terms of interpretation of rheological properties of materials

Slipping zone location in squeeze flow

the original publication is available at http://www.springerlink.com/content/f1611lmr64836780/International audienceIn squeeze flow rheometry, the main problem is the boundary condition between the squeezed material and the plates. Therefore, the crucial assumption is to know the location and the shape of the sample part where wall slip may or may not occur. This question is investigated from experimental results. For this, squeeze flow experiments are carried out to visualize the flow pattern at the walls. Influence of boundary conditions is particularly studied using different plate surface condition. As a result, with wall slipping conditions, we propose a flow modelling divided into two zones: a circular central zone of the sample sticks on the plates and, beyond that zone, the sample slips at the plates with friction

Le test de compression simple : mise en oeuvre sur un analyseur de texture et exploitation en présence de fluides viscoplastiques

National audienc

Le test de compression simple : mise en œuvre et exploitation en présence de fluides alimentaires

National audienc

Squeezing flow for rheological characterisation of food materials,

International audienceThe rheological behaviour of commercial mayonnaises is investigated by means of a squeeze flow rheometer. Theoretical study is based on plastic flow analysis. Data analysis of this test shows that the mayonnaises behaviour at low shear rate is mainly plastic. Result analysis allows differentiating the material rheological response and the material friction effect on the plates. Results highlight the influence of the boundary conditions and roughness conditions. The increasing of compression speed changes the value of apparent plastic yield value and the friction yield value. A tribological law links friction stress and sliding velocity. The interface effects are not the same for all the tested mayonnaises. A probable change of internal structure explains this phenomenon. Finally, the simple compression test proved suitable for food materials characterisation