The first part of this work deals with modelling and simulating flow and mass tranfer in trickle-bed reactors. Using spatial averaging of microscopic conservation equations, the porous medium was considered homogeneous. We proposed different models taking into account the system's wall effect. They were solved and comparison with previous experimental results allowed us to choose the best models. The development of more complex models using our experimental results should lead to more accurate simulations. In the second part, we used microelectrodes inserted in a pore to measure velocity gradient, thus giving information about local hydrodynamics. For single phase liquid flow, flow regime transitions could be determined. A turbulent behaviour at high flow rate was observed, and could be characterized using auto- and intercorrelation functions. A surface renewal model gave access to mean velocity gradients, with the renewal times being computed using VITA (Variable Interval Time Averaging). For gas-liquid flows, electrochemical probes do not give interesting results. Nonetheless, pulsed flows could be studied using wall pressure transducers.
