Binder jetting (BJ) is an additive manufacturing process (also called 3D printing), that consists in jetting a binder on a powder bed made of metallic or ceramic particles, so that to build a part from a 3D model. Once the binder has cured, the part is extracted from the powder bed and sintered. A major challenge of this process is to predict the state of the part after printing (density, homogeneity, defects). Printing strategy, powder size/shape and binder type all have an impact on the part before densification. The aim of this thesis is to study the interaction between the binder and the powder during the printing process. Ultimately, this should help to optimize the process. The thesis will focus on developing a model for droplet infiltration in a powder bed. To achieve this objective, the proposal is to use innovative numerical methods to model the fluid-structure interaction operating in the powder bed, taking into account capillary forces and dynamic effects (droplet fragmentation, particle displacement). Experimental investigations are also planned, firstly to calibrate the numerical parameters associated with the model, and secondly to validate the model. In fact, a dedicated experimental bench was previously developed, and will be used to characterize the surface state of the powder bed before and after infiltration.