TY - GEN

T1 - Axial-Radial Diffuser With Integrated Exhaust Hood for An Automotive Turbocharger With Axial Turbine

AU - Kuestner, Christoph

AU - Seume, Joerg R.

N1 - Funding Information: The results presented here were carried out on the cluster system at the Leibniz Universitaet Hannover, Germany, under Grant. This support is gratefully acknowledged.

PY - 2021/9/16

Y1 - 2021/9/16

N2 - Exhaust hoods with an integrated axial-radial diffuser use the kinetic energy downstream of a turbine for static pressure recovery. This is especially useful in applications with limited axial space behind the turbine. So far, such exhaust hoods have been used almost exclusively in larger turbomachinery such as maritime turbochargers and steam turbines, where an axial turbine is typically installed. In combination with an axial turbine, an exhaust hood can result in a very powerful and space-efficient turbine design, especially under highly pulsating inflow conditions. Both are important requirements for automotive turbochargers. Therefore, the application of such an exhaust hood in a small automotive turbocharger is investigated in this paper; this turbocharger also uses an axial turbine. In the first step, a preliminary design is developed, based on a design approach for steam turbine exhaust hoods. The resulting design is examined with a 3D CFD model to determine efficiency and turbine performance. Subsequently, the design is improved by modifying the exhaust hood geometry such as to further improve the overall efficiency of the turbine. Finally, the CFD evaluation for the operating point investigated reveals an increased power output and a higher overall turbine efficiency compared to the initial design. A resulting design guideline for exhaust hoods with an integrated axial-radial diffuser is included.

AB - Exhaust hoods with an integrated axial-radial diffuser use the kinetic energy downstream of a turbine for static pressure recovery. This is especially useful in applications with limited axial space behind the turbine. So far, such exhaust hoods have been used almost exclusively in larger turbomachinery such as maritime turbochargers and steam turbines, where an axial turbine is typically installed. In combination with an axial turbine, an exhaust hood can result in a very powerful and space-efficient turbine design, especially under highly pulsating inflow conditions. Both are important requirements for automotive turbochargers. Therefore, the application of such an exhaust hood in a small automotive turbocharger is investigated in this paper; this turbocharger also uses an axial turbine. In the first step, a preliminary design is developed, based on a design approach for steam turbine exhaust hoods. The resulting design is examined with a 3D CFD model to determine efficiency and turbine performance. Subsequently, the design is improved by modifying the exhaust hood geometry such as to further improve the overall efficiency of the turbine. Finally, the CFD evaluation for the operating point investigated reveals an increased power output and a higher overall turbine efficiency compared to the initial design. A resulting design guideline for exhaust hoods with an integrated axial-radial diffuser is included.

UR - http://www.scopus.com/inward/record.url?scp=85115723376&partnerID=8YFLogxK

U2 - 10.1115/GT2021-58600

DO - 10.1115/GT2021-58600

M3 - Conference contribution

AN - SCOPUS:85115723376

T3 - Proceedings of the ASME Turbo Expo

BT - Turbomachinery - Multidisciplinary Design Approaches, Optimization, and Uncertainty Quantification; Radial Turbomachinery Aerodynamics; Unsteady Flows in Turbomachinery

PB - American Society of Mechanical Engineers(ASME)

T2 - ASME Turbo Expo 2021

Y2 - 7 June 2021 through 11 June 2021

ER -