The aim of this work is the experimental validation of a transient ejector model for hybrid system applications. It is a mandatory step to perform the transient analysis of the whole plant to avoid critical situations and to develop the control system. So, the anodic recirculation test rig, already used in previous works to study the ejector design validating the steady-state 0-D and CFD models, has been used in this work to perform tests at transient conditions and to validate the ejector transient model.An initial validation has been carried out at steady-state conditions, then the ejector transient model has been successfully compared with the experimental data also at unsteady conditions. A second step has been carried out to better investigate the whole anodic recirculation system. So, the validated ejector transient model has been connected with the components necessary to simulate the pipes, the valves and the anodic volume. Also in this case, the calculated results have been successfully compared with the experimental data obtained with the laboratory test rig. The final part of the paper is devoted to the results obtained at impulse conditions. In fact, this work investigates the effects on the anodic ejector and on the whole anodic circuit coming from fuel line impulses due to possible unsteadiness conditions. The results obtained with impulses at different frequency values have been successfully compared with the experimental data.
