Influence des circuits de liaison moteur/compresseur sur le fonctionnement des moteurs Diesel à suralimentation bi-étagée
In pulsed flow, the surge line of a centrifugal compressor is highly dependent on the upstream and downstream piping systems. In this study, the shift of this surge line in the case of two two-stage turbocharged marine Diesel engines is calculated using a numerical simulation of the compressor/pipe work assembly for each engine. The linkage of two programs using the ACSL language (in a global solution procedure) allows the understanding and quantification of the connection circuit's influence on the operating limits. The tendencies observed on the test bed are reproduced by the simulation, confirming the chosen methodology. This procedure also permits an analysis and understanding of the observed phenomena, especially the identification of the compressor which initiated the surge effects and the explanation of irregularities in the operating limit.
Long pulse operation has an important impact on the design and utilization of a neutral beam injection system. This paper, first describes briefly the injectors designed for ITER FEAT as they are the first to be designed for long pulse operation under conditions approaching those that will be experienced in future machines. The important consequences of long pulse operation on the injector design will be then discussed, and finally some suggestions will be made for future, continuously operating systems.