Axial turbine design for a twin-turbine heavy-duty turbocharger concept

Nicholas Anton, Magnus Genrup, Carl Fredriksson, Per Inge Larsson, Anders Christiansen-Erlandsson

Research output: Chapter in Book/Report/Conference proceedingPaper in conference proceedingpeer-review

Abstract

In the process of evaluating a parallel twin-turbine pulseturbocharged concept, the results considering the turbine operation clearly pointed towards an axial type of turbine. The radial turbine design first analyzed was seen to suffer from suboptimum values of flow coefficient, stage loading and blade-speed-ratio. Modifying the radial turbine by both assessing the influence of "trim" and inlet tip diameter all concluded that this type of turbine is limited for the concept. Mainly, the turbine stage was experiencing high values of flow coefficient, requiring a more high flowing type of turbine. Therefore, an axial turbine stage could be feasible as this type of turbine can handle significantly higher flow rates very efficiently. Also, the design spectrum is broader as the shape of the turbine blades is not restricted by a radially fibred geometry as in the radial turbine case. In this paper, a single stage axial turbine design is presented. As most turbocharger concepts for automotive and heavy-duty applications are dominated by radial turbines, the axial turbine is an interesting option to be evaluated for pulsecharged concepts. Values of crank-angle-resolved turbine and flow parameters from engine simulations are used as input to the design and subsequent analysis. The data provides a valuable insight into the fluctuating turbine operating conditions and is a necessity for matching a pulse-turbocharged system. Starting on a 1D-basis, the design process is followed through, resulting in a fully defined 3D-geometry. The 3Ddesign is evaluated both with respect to FEA and CFD as to confirm high performance and durability. Turbine maps were used as input to the engine simulation in order to assess this design with respect to "on-engine" conditions and to engine performance. The axial design shows clear advantages with regards to turbine parameters, efficiency and tip speed levels compared to a reference radial design. Improvement in turbine efficiency enhanced the engine performance significantly. The study concludes that the proposed single stage axial turbine stage design is viable for a pulse-turbocharged sixcylinder heavy-duty engine. Taking into account both turbine performance and durability aspects, validation in engine simulations, a highly efficient engine with a practical and realizable turbocharger concept resulted.

Original languageEnglish
Title of host publicationTurbomachinery
PublisherAmerican Society Of Mechanical Engineers (ASME)
Volume2B-2018
ISBN (Print)9780791851005
DOIs
Publication statusPublished - 2018
EventASME Turbo Expo 2018: Turbomachinery Technical Conference and Exposition, GT 2018 - Oslo, Norway
Duration: 2018 Jun 112018 Jun 15

Conference

ConferenceASME Turbo Expo 2018: Turbomachinery Technical Conference and Exposition, GT 2018
Country/TerritoryNorway
CityOslo
Period2018/06/112018/06/15

Subject classification (UKÄ)

  • Energy Engineering

Keywords

  • Axial
  • Design
  • Turbine
  • Turbocharging

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