TY - JOUR

T1 - Experimentally validated extension of the operating range of an electrically driven turbocharger for fuel cell applications

AU - Schoedel, Markus

AU - Menze, Marco

AU - Seume, Joerg R.

N1 - Funding Information: Funding: This research was funded by the Federal Ministry of Transport and Digital Infrastructure (BMVI) grant number 03B10105C/2. Funding Information: Acknowledgments: The investigations presented in this paper are part of the research project “Charging of Fuel Cell Systems through Interdisciplinary Developed Electrically Driven Air Compressors” (ARIEL). The authors thank the Federal Ministry of Transport and Digital Infrastructure (BMVI) which financially supported the work within the framework of the National Innovation Programme (NIP) Hydrogen and Fuel Cell Technology as well as the NOW GmbH which coordinated the funding guideline. The authors would also like to gratefully acknowledge the entire project consortium consisting of the Volkswagen AG and all the participating institutes of the University of Braunschweig and the Ostfalia University of Applied Sciences.

PY - 2021/12/2

Y1 - 2021/12/2

N2 - From an aerodynamic point of view, the electric turbocharger for the air supply of an automotive fuel cell faces difficult requirements: it must not only control the pressure level of the fuel cell, but it also has to operate with very high efficiency over a wide range. This paper explores features for the compressor and the turbine of an existing electric turbocharger, which are intended to meet the specific requirements of a fuel cell in an experimentally validated numerical study. Adjustable diffuser or nozzle vanes in the compressor and turbine achieve wider operating ranges but compromise efficiency, especially because of the necessary gaps between vanes and end walls. For the turbine, there are additional efficiency losses since the pivoting of the nozzle vanes leads to incidence and thus to flow separation at the leading edge of the nozzle vanes and the rotor blades. An increase in the mass flow and a slight efficiency improvement of the turbine with the low solidity nozzle vanes counteracts these losses. For the compressor, a reduction in the diffuser height and its influence over the operating range and power consumption yields an increase in surge margin as well as in maximum efficiency.

AB - From an aerodynamic point of view, the electric turbocharger for the air supply of an automotive fuel cell faces difficult requirements: it must not only control the pressure level of the fuel cell, but it also has to operate with very high efficiency over a wide range. This paper explores features for the compressor and the turbine of an existing electric turbocharger, which are intended to meet the specific requirements of a fuel cell in an experimentally validated numerical study. Adjustable diffuser or nozzle vanes in the compressor and turbine achieve wider operating ranges but compromise efficiency, especially because of the necessary gaps between vanes and end walls. For the turbine, there are additional efficiency losses since the pivoting of the nozzle vanes leads to incidence and thus to flow separation at the leading edge of the nozzle vanes and the rotor blades. An increase in the mass flow and a slight efficiency improvement of the turbine with the low solidity nozzle vanes counteracts these losses. For the compressor, a reduction in the diffuser height and its influence over the operating range and power consumption yields an increase in surge margin as well as in maximum efficiency.

KW - Electrical turbocharger

KW - Fuel cell air supply

KW - Operating range extension

UR - http://www.scopus.com/inward/record.url?scp=85121698061&partnerID=8YFLogxK

U2 - 10.3390/machines9120331

DO - 10.3390/machines9120331

M3 - Article

AN - SCOPUS:85121698061

VL - 9

JO - Machines

JF - Machines

IS - 12

M1 - 331

ER -