<p class="MsoNormal" style="text-align: justify">Exhaust hoods with an integrated axial-radial diffuser offer the opportunity to use the kinetic energy downstream of a turbine for static pressure recovery 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 with integrated axial-radial diffuser 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 smaller automotive turbocharger is investigated in this paper; this turbocharger also&nbsp; uses an axial turbine. In a 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 the pressure recovery coefficient and total pressure losses. Subsequently, a design optimization is performed on the geometry to further improve the pressure recovery coefficient. Finally, the CFD evaluation for the operating point investigated reveals an increased static pressure recovery and reduced total pressure losses compared to the initial design. A resulting design guideline for exhaust hoods with integrated axial-radial diffuser is included.</p>

Axial-Radial Diffuser with Integrated Exhaust Hood for an Automotive Turbocharger with Axial Turbine

Paper Proceedings: https://asmedigitalcollection.asme.org/GT/GT2021/volume/84898

Turbo Expo 2021

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