Impact of distributor zone design on flow uniformity in metal foam cooling flow fields of PEMFC

In a proton exchange membrane fuel cell, the distributor zone of a metal foam cooling flow field directly affects coolant distribution among the cooling branches and the resulting temperature uniformity. Based on the optimized structural parameters of the main metal foam cooling flow field, a three-dimensional numerical model incorporating the core components of a single cell and the distributor zone was developed. This study systematically investigated how three key design parameters, namely distributor zone shape, circular hole diameter, and number of circular holes, regulate coolant flow uniformity. The circular structure was retained as the baseline configuration because of its favorable thermal characteristics and geometric adjustability. The results showed that the optimal circular hole diameter was 1.5 mm, yielding an average mass flow deviation of 26.05 %. With this diameter fixed, the configuration with 14 circular holes exhibited the lowest average mass flow deviation and coefficient of variation among the examined cases, at 17.93 % and 27.26 %, respectively, thereby achieving the best trade-off between flow uniformity and hydraulic resistance. This study clarifies how the structural parameters of the distributor zone regulate coolant distribution and provides key technical support for the integrated design and performance optimization of cooling systems at the stack level.