Design and Analysis on Separator-Ejector Integrated Device of Hydrogen Recirculation System in Proton Exchange Membrane Fuel Cell 2023-01-0498

Hydrogen recirculation system (HRS) is one of the main subsystems of proton exchange membrane fuel cell (PEMFC) system, and an HRS with high performance and low cost is essential to improve the fuel cell lifetime and efficiency. The ejector is becoming an effective alternative to the hydrogen circulation pump in the hydrogen recirculation system because of its small size, low cost and no parasitic power. However, the conventional ejector can only operate at the limited output power of the fuel cell. In order to improve this drawback, a hydrogen recirculation system with a separator-ejector integrated device is proposed. The hydrogen recirculation system based on the integrated device can make the space more compact, reduce the condensation effect of the piping, improve the fuel cell performance and reduce the cost. The design and integration method of the ejector and gas-water separator in this hydrogen recirculation system are introduced. The hydrodynamic model of the integrated structure is established and simulations are performed. A hydrogen recirculation system test platform is also built to experimentally analyze the hydrogen recirculation characteristics and verify the simulation model based on the experiments. Through the simulation study, the performance of the hydrogen recirculation system with the separated structure ejector is analyzed. The simulation results show that, compared with the conventional hydrogen recirculation system, the hydrogen recirculation system with the separator-ejector integrated device reduces the condensation and pressure drop in the tube, improves the hydrogen recirculation efficiency, and can cover a wider power output range of the PEMFC stack, from the range of 45kW to 100kW to the range of 30kW to 100kW, which can effectively improve the fuel cell performance and reduce the cost.