Session: 19-02 Applications

Paper Number: 153580

Experimental Investigation of Condensing Two-Phase Flows in a Turbocharger Turbine for Fuel Cell Applications 

The development of turbocharger turbines for fuel cell (FC) applications introduces unique challenges due to the working fluid. High humidity air as exhaust gas from the fuel cell can lead to condensation effects that are absent in conventional turbocharger turbines. This can have an influence on the efficiency as well as on the durability of components due to coarse water droplet erosion. There exist several experimental as well as numerical investigations on the condensation effects of humid air, but there is no evident data of droplet measurements in a FC turbocharger turbine application.

To address this, experimental investigations were conducted to examine condensing two-phase flows in an FC turbocharger turbine. A dedicated test section was developed to acquire detailed data of the expansion of the flow, the flow field as well as the droplet distribution at a defined cross section downstream of the turbine.

Generic inlet conditions reproduce the FC exhaust gas with varying pressure, temperature and relative humidity. Droplet distributions are precisely determined by means of light extinction method. The flow field is measured using a 5-hole probe featuring thermocouples. A detailed design of experiments (DOE) was set-up to assess the influence of the inlet conditions on droplet formation.

The test data acquired was used to validate CFD simulations modeling the expansion of humid air, employing an adapted phase transition model. This model has been introduced in a paper presented at the Turbo Expo 2024 (GT2024-122095). The CFD simulation results correlate well to test data, especially what regards the flow field and the overall trends in liquid volume fraction and droplet diameters.

The proposed paper presents the instrumentation developed for measurements of condensing flows in FC turbines and discusses the agreement of CFD simulation results to test data.

Presenting Author: Dominik Bezler Institute of Thermal Turbomachinery and Machinery Laboratory, University of Stuttgart

Presenting Author Biography: Since 2022: Research Assistant at the Institute of Thermal Turbomachinery and Machinery Laboratory (ITSM)
2019 - 2022: Master of Science in Technology Management at the University of Stuttgart
2017-2019: Research and Development Engineer at Brückner Trockentechnik GmbH & Co. KG
2014 - 2017: Bachelor of Engineering in Mechanical Engineering at the Baden-Wuerttemberg Cooperative State University (DHBW) Stuttgart

Authors:

Dominik Bezler Institute of Thermal Turbomachinery and Machinery Laboratory, University of Stuttgart
Adem Tosun Institute of Thermal Turbomachinery and Machinery Laboratory, University of Stuttgart
Fabian F. Müller Institute of Thermal Turbomachinery and Machinery Laboratory, University of Stuttgart
Charlotte Malkinson Cummins Components & Software - Turbo Technologies
Damian M. Vogt Institute of Thermal Turbomachinery and Machinery Laboratory, University of Stuttgart