Influence of key design parameters on the aerodynamic performance of a centrifugal compressor volute for turbocharger applications

A centrifugal compressor volute should ideally collect the pressurized flow at the diffuser outlet and convey it to the outlet piping as efficiently as possible. The total pressure loss related to the conversion of a radial flow into an axial one, however, is often not negligible, especially for applications where severe dimensional constraints are given, such as in turbochargers applications. Having a reliable tool for the performance prediction of the volute, flexibly adaptable to external constraints, is then pivotal in the design phase of new prototypes. Within this context, a fully parametric tool has been developed. Based on few geometrical inputs, it allows an automatic generation of both the CAD model of the volute and the numerical setup for the CFD calculation. The shape of the volute cross-section can be fully customized and automatically adapted to the azimuthal distributions of the area and centroid radius given in input by the user. The volute tongue can be also freely modified in terms of shape, azimuthal position and width. An extensive parametric analysis was then carried out, aimed at investigating the influence of key design parameters needed to define the shape of the volute on the internal fluid dynamics. Particular attention was paid to the tongue modelling strategy and shape, being it the critical feature for the volute flow performance. As a result, some annotated indications are given to define the first layout of a volute when approaching a new design.