Multi-channel casing design for radial turbine operation control

Multiple Exhaust DUct with Source Adjustment (MEDUSA) is a novel concept, which may be used to control the operation of radial turbines in turbochargers. This technique is based on replacing the traditional spiral volute with a Multi-channel Casing (MC) to provide turbine inlet area controllability, which in turn will control the inlet flow angle. When replacing a traditional radial turbine casing featuring a single volute by a multichannel casing variant, it is crucial to ensure comparable mass flow characteristics. Not only should the effect of the casing replacement on the performance be considered, but also the influence of the different geometrical parameters of the new casing. The present study presents and discusses the methodology for substituting the spiral volute with multichannel casing while conserving the mass flow characteristics. Also, a parametric study takes place to monitor the effect of the new casing geometrical parameters on the turbine performance. First, a flow simulation of the radial turbine with the original spiral casing has been performed and validated with experimental results to establish a reliable and robust model giving the ability to study new casing designs. Secondly, two different designs for the multi-channel casing have been studied to replace the traditional one. Finally, a parametric study is presented to assess the new technique deeply. The results show the possibility of replacing the traditional spiral volute with a curved MC while conserving the same turbine performance map and sufficient turbine efficiency.