Characterization of the Discharge Flow of a Dual Volute Axi-Centrifugal Gas Turbine Compressor

摘要

To contribute to further understanding of the unique dual-discharge volute design of the Rolls-Royce Allison 250-C20B engine, a rig has been constructed to characterize the compressor discharge flow. A compressor module for this gas turbine engine was powered by an automotive engine in parallel with a modified turbine module operating in the cold compressor discharge flow. Continuous operation at 70% and 80% speed has been achieved while conducting simultaneous discharge pressure traverses. A non-uniform discharge Mach number profile was observed in each port with no significant asymmetry. Evidence of the influence of the volute geometry was observed in the discharge Mach number profile. The discharge mass flow rate from each port was observed to differ by as much as 4%. This observation could offer an explanation for the evidence of regions of higher turbine inlet temperature that has been observed by others.