TY - GEN

T1 - Variable turbine geometry for an automotive turbocharger with a small axial turbine

AU - Kuestner, Christoph

AU - Helmsen, Eike

AU - Seume, Joerg R.

PY - 2024/9/6

Y1 - 2024/9/6

N2 - The paper examines the implementation of a variable turbine geometry (VTG) and the reduction of its tip leakage losses in a small axial turbine turbocharger for charging lean-burn internal combustion engines. Due to the small turbine size, a reduction in the number of vanes and a redesign was required to match the design point of the non-adjustable stator. Subsequently, discs were added to the vanes’ ends to seal the radial gaps in the VTG. The turbine size prohibited a full sealing on the hub side, leaving small gaps at the leading edge (LE) and trailing edge (TE). To evaluate their influence, three gap configurations of the adjusted design (constant hub gap, partial gaps at LE and TE, and non-gap) were compared with the initial design using CFD simulations. The results showed that the partial gap configuration was able to reduce the maximum mass flow rate deviations at the investigated turbine speed down to 0.8% while maintaining the same turbine efficiencies as the non-gap configuration. Finally, the performance map was evaluated for the partial gap configuration, which showed that the turbine required a slightly larger pivot angle range to meet the specified requirements.

AB - The paper examines the implementation of a variable turbine geometry (VTG) and the reduction of its tip leakage losses in a small axial turbine turbocharger for charging lean-burn internal combustion engines. Due to the small turbine size, a reduction in the number of vanes and a redesign was required to match the design point of the non-adjustable stator. Subsequently, discs were added to the vanes’ ends to seal the radial gaps in the VTG. The turbine size prohibited a full sealing on the hub side, leaving small gaps at the leading edge (LE) and trailing edge (TE). To evaluate their influence, three gap configurations of the adjusted design (constant hub gap, partial gaps at LE and TE, and non-gap) were compared with the initial design using CFD simulations. The results showed that the partial gap configuration was able to reduce the maximum mass flow rate deviations at the investigated turbine speed down to 0.8% while maintaining the same turbine efficiencies as the non-gap configuration. Finally, the performance map was evaluated for the partial gap configuration, which showed that the turbine required a slightly larger pivot angle range to meet the specified requirements.

UR - http://dx.doi.org/10.33737/gpps24-tc-026

U2 - 10.33737/gpps24-tc-026

DO - 10.33737/gpps24-tc-026

M3 - Aufsatz in Konferenzband

BT - Proceedings of Global Power & Propulsion Society

ER -