INFLUENCE OF THE NETWORK GEOMETRY ON THE SURGECHARACTERISTICS OF A CENTRIFUGAL COMPRESSOR.

International audienceDuring the use of centrifugal compressor for turbocharging diesel engines, the compressor is connected to one circuit, more or less complex including capacities and lengths pipes (air filter, RAS : supercharger air cooler, bends, resonator…) These different network geometries have a very high influence on the « surge line » position (see figure 1), as well as on the surge loop (figure 2). Figure 1 Figure 2. This surge loop area (pressure ratio vs mass flow-rate fluctuations) represents the unsteady pressure fluctuations and mass flow fluctuations affecting the centrifugal compressor and the diesel engine. In this paper, we propose an analysis of surge characteristics of a centrifugal compressor, and more particularly the evolution of its « surge loop » which characterizes the intensity of the unsteady pressure fluctuations (very dangerous for the compressor) and mass flow-rate fluctuations (disturbing and possibly dangerous for the engine)