The Causes and Optimization Strategies of “Barrel Effect” in the Start-Up Stage of Fuel Cell Systems Based on Multi-Scale, Multi-Phase Fusion Methods

Abstract

Based on a multi-scale, multiphase integration of research methods, including experiments on a 19 kW fuel cell system, single-cell tests of fuel cells, and three-dimensional multiphase single-cell computational fluid dynamics (CFD) simulations, an equivalent analytical model is established to investigate the causes and solution countermeasures of the “Barrel Effect” in the start-up-phase of fuel cell systems. The study explores optimal flow conditions under heavy load conditions and simultaneously conducts optimization of flow field dimensions to address flooding and low voltage issues under low air inlet conditions. The research findings indicate that during the start-up process at high current density, inadequate gas supply and uneven flow distribution result in excessively low voltage in individual cells, leading to shutdown. The equivalent analytical model analysis results reveal that under low air inlet conditions, severe flooding occurs in individual cells under heavy load conditions. Inlet flow optimization results show that with increasing flow, the voltage of individual cells first increases and then levels off, and the flooding issue is essentially resolved when the flow exceeds 1000 ml/min. Flow field size optimization indicates that, without increasing the inlet flow, significant improvement in individual cell performance and effective flooding prevention can be achieved through flow field size optimization. The results provide important references for the optimization of fuel cells in practical applications.

Keywords: Equivalent analysis model, multi-scale multi-phase fusion, flooding problem, optimum flow rate condition point, flow field size optimization