Development of a Test Stand for Electric Fuel Cell Turbocharger Integrity Testing

Abstract This publication describes the modification of a classical hot-gas turbocharger test bench to reproduce the exhaust conditions of a PEM fuel cell stack. Characterization of liquid-water-specific separators and demonstration on how boundary condition variation-such as particle diameter and water content-is possible with a modified classical hot-gas test bench leading to erosion of an aluminium turbine wheel will be detailed. De-ionized water is generated, pressurized, heated, and injected into the main mass flow through an air–water nozzle. By varying the air and water nozzle supply pressures, different droplet sizes and water flow rates can be introduced into the stream, enabling systematic characterization of water separators. The turbine is subjected to efficiency, eigenfrequency measurements, and three-dimensional scanning. These measurements are used to monitor and assess the critical impact of erosion on turbine integrity and performance. Centrifugal separators exhibited greater stability under the examined PEM exhaust conditions, whereas mesh-type separators showed weaknesses when exposed to increased main mass flows. Erosion was observed at the leading-edge suction side of the turbine blades; however, the damage was primarily cosmetic. The structural integrity of the turbine wheel remained unchanged throughout the testing period. Although the classical hot-gas test bench was originally designed for high-pressure, high-temperature combustion exhaust gases, a set of targeted modifications enabled its use in low-temperature, liquid-water-rich environments.