Numerical investigation of a radial turbine with variable nozzle geometry for fuel cell systems in automotive applications

Menze, Marco; Schoedel, Markus; Seume, Joerg R.

doi:10.29008/etc2021-748

Cited by 5 publications

(4 citation statements)

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“…Further, turbine design theory needs to be developed further to account for the effects of condensation and liquid water in humid air. This should include variable geometry turbines, such as those proposed by Menze et al for PEMFC applications [56].…”

Section: Discussionmentioning

confidence: 99%

On the Impact of Condensation and Liquid Water on the Radial Turbine of a Fuel Cell Turbocharger

Wittmann¹,

Lück²,

Bode³

et al. 2022

Machines

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The air-management system of a proton exchange membrane fuel cell (PEMFC) is responsible for supplying the fuel cell stack with ambient air at appropriate conditions. The compressor of the air-management system can be partly driven by utilizing the fuel cell exhaust gas in a turbine. The fuel cell exhaust is partially or fully saturated with water vapor. When the exhaust gas is expanded in the turbine, supersaturation occurs. This leads to the nucleation of droplets and their subsequent growth by condensation. This study provides an overview and understanding of the various phenomena caused by condensation and liquid water in the turbine of a PEMFC air-management system. The basis for this work is previously published numerical simulations that focused on individual aspects of the above phenomena. The present work revisits these results and puts them in context to provide a comprehensive understanding. Important phenomena are the effects of condensation on turbine performance through phase change losses, release of latent heat and thermal throttling. In addition, the released latent heat offers a power potential for downstream turbine stages. Through these effects, condensation can also impact the entire air-management system. However, condensation may occur unevenly, causing a circumferential asymmetry of the turbine outflow. Liquid water in the turbine can lead to droplet erosion, corrosion, and water-induced damage. In summary, it is essential to consider condensation and liquid water when developing turbines for PEMFC air-management systems.

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Section: Discussionmentioning

confidence: 99%

On the Impact of Condensation and Liquid Water on the Radial Turbine of a Fuel Cell Turbocharger

Wittmann¹,

Lück²,

Bode³

et al. 2022

Machines

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show abstract

“…On the other hand, aligning the turbine with the stack operating line while maximizing the efficiency is crucial. Consequently, Menze et al [163] studied variable turbine geometries, specifically exploring the variable nozzle turbine and sliding nozzle turbine. The overarching objective of achieving optimal system performance requires the careful consideration of the interplay between the turbomachinery components, fuel cell stacks, and auxiliary devices.…”

Section: Innovative Applicationsmentioning

confidence: 99%

Instability Phenomena in Centrifugal Compressors and Strategies to Extend the Operating Range: A Review

Cravero,

Marsano

2024

Energies

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Centrifugal compressors are widely used in different fields. Their design requires high performance and a wide operating range, where, at lower mass flow rates, unstable flow dynamic phenomena occur, which are extremely harmful and, at the same time, complex to fully understand. This review paper presents the main research from the last 40 years on the subject of instability in centrifugal compressors, aiming to clarify the main (sometimes contradictory) causes, classifying them according to the component in which they are triggered or the interaction between them. Importance is given to works that develop criteria for the identification of the stability limit with simplified models. The main techniques used to extend the stability limit are also presented by distinguishing between passive and active fixed-flow control methods; moreover, the main works on variable geometry techniques are reported, showing the advantages and disadvantages of their use. Finally, an overview of the innovative applications of centrifugal compressors, such as fuel cells, is presented. The aim of this review is to highlight the continued interest in this field of study and provide the tools to understand the different unstable mechanisms and techniques used to extend the operating limit.

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“…The rotor and stator mesh are structured and consist of 756k nodes for each rotor blade and 492k nodes for each stator vane. The volute mesh is unstructured, has 1764k nodes and was provided by Menze et al (2021). The grid convergence index (GCI) is less than 3% and the average y + is less than 1.…”

Section: Turbine and Numerical Modelling Approachmentioning

confidence: 99%

Investigation of Water Droplet Erosion in the Radial Turbine of a Fuel Cell Turbocharger

Wittmann¹,

Lück²,

Bode³

et al. 2022

Proceedings of Global Power &Amp; Propulsion Society

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Radial turbines of fuel cell turbochargers are prone to water droplet erosion (WDE). Test bench runs of such a turbine showed erosion zones on the rotor suction side near the leading edge and on the stator suction side near the trailing edge. The aim of this study is to analyze this erosion and determine which droplet trajectories are responsible for it. For this purpose, Euler-Lagrange simulations of the non-equilibrium condensing flow are analyzed with regard to droplet deposition. It is shown that the droplets originating from condensation are not responsible for the observed erosion. It is therefore investigated whether an inflow of droplets from the fuel cell itself can be responsible for the erosion. The study indeed shows that such droplets can form wall films on rotor and stator. Therefore, the observed erosion is most likely the result of droplets formed by the break-up of wall films at the trailing edge of the stator vanes and also at the leading edge of the rotor blades.

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Numerical investigation of a radial turbine with variable nozzle geometry for fuel cell systems in automotive applications

Cited by 5 publications

References 0 publications

On the Impact of Condensation and Liquid Water on the Radial Turbine of a Fuel Cell Turbocharger

On the Impact of Condensation and Liquid Water on the Radial Turbine of a Fuel Cell Turbocharger

Instability Phenomena in Centrifugal Compressors and Strategies to Extend the Operating Range: A Review

Investigation of Water Droplet Erosion in the Radial Turbine of a Fuel Cell Turbocharger

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