Laboratoire Matière et Systèmes Complexes

Le lundi 29 janvier 2018, en salle 454A à 11h30.

A numerical modeling for thawing estimation in application of SCR system development

Zejun Hu, Laboratoire MSC

The SCR (Selective Catalytic Reduction) system is chosen by automobile manufacturers for meeting lowered NOx standards for the world wild marked. However, the reductant AdBlue (urea solution) freezes at -11°C and a heating process is required at low temperature. Plastic Omnium, one of the main SCR system suppliers, asks a numerical model for helping heating strategy study and validation by integrating the numerical model in their control software platform (model in the loop). A volume finite method based thermodynamic and fluid dynamic model is developed for simulating the phase change phenomena of AdBlue. Some validation work is also done by comparing with experimental tests.

Solidification experiments on static and mobile substrates, for varying feeding rates.

Rémy Herbaut, Laboratoire MSC

Inspired by problems of 3D printing that are currently motivating a large number of works, we consider two kinds of solidification problems of a liquid drop on a cold substrate :
 In a first set of experiments, a liquid drop deposited on a cool substrate, below the melting temperature, is feeded with liquid at constant rate by a very thin needle, in contact with the top of the drop. This problem generalizes the cusp formation problem on a static drop investigated recently by several authors (refs). We show that, depending on the control parameters, two very different shapes are observed, for which we also provide a simple model, that is in very good agreement with experiments.
 In a second set of experiments, a drop of constant volume is maintained static on a moving substrate. Instabilities of the advancing contact lines are observed with a transition between continuous sliding and stick-slip behavior. We also propose a simple kinematical model that well describes this complex behavior onset. Experiments that combine both effects (continuous supply and substrate motion) are also under way. Preliminary observations will be reported too.