## 1 Introduction  
The Proton Exchange Membrane Fuel Cell (PEMFC) shows promising advantages for its high efficiency and zero emission compared with internal combustion engines [1; 2]. The membrane would show low resistance with ample water inside, which means the reactive gases need humidification. The area with a relatively high electrochemical reaction rate has a higher risk of flooding because the product of the reaction is also water [3; 4]. The operating temperature range of PEMFC is determined by the physicochemical properties of the membrane [5]. Therefore, heat and water management is crucial to PEMFC [5; 6]. The mass transport of reactive gases is also essential to the performance and reliability of PEMFC. The uniform distribution of reactive gases helps reduce the risk of high temperatures and flooding in local areas in the flow field [7; 8; 9]. There are several researches about the mass transport in PEMFC. [PERSON] et al. designed and tested a visible single PEMFC, measured the distribution of current density and temperature, and studied the shape and movement of water drops in the flow channel [10]. [PERSON] et al. conducted a durability test and researched the degradation mechanisms of the components in PEMFC by many measuring means [11]. [PERSON] et al. established the gas diffusion layer (GDL) structure by X-ray measurements and researched the movement of water drops in the GDL by the lattice Boltzmann method (LBM) [12]. [PERSON] et al. studied the hysteresis of output voltage by a visualization experiment and Electrochemical Impedance Spectroscopy (EIS), built a 1-D PEMFC model to calculate, and indicated the importance of GDL wettability to liquid water transport [13]. [PERSON] et al. built a 2-DPEMFC model to research the effect of water transport in the cathode on the performance of PEMFC [14]. [PERSON] et al. studied the O\({}_{2}\) transport in the membrane electrode assembly (MEA) by calculation and experiment [15]. [PERSON] et al. studied the effect of the accumulation of water and N\({}_{2}\) in anode on the performance by a 3-D transient calculation [16]. Some research focuses on the influence of flow field structure on the performance of PEMFC. [PERSON] et al. modeled the fuel cell and researched the influence of different flow field structures on the temperature distribution of commercial PEMFC [17]. [PERSON] et al. simulated the cathode variable cross-section flow channel model to improve the performance of PEMFC [18]. [PERSON] et al. designed and calculated a serpentine flow field with rib grooves to optimize the performance of PEMFC [19]. [PERSON] et al. researched the influence of bio-inspired flow channels on the performance of PEMFC by simulation and experiment [20]. [PERSON] et al. made a CFD model of a PEMFC and analyzed the influence of channel distribution on the cathode current [21]. Each flow field design has certain disadvantages. The parallel flow field shows worse distribution uniformity of reactive gases than the serpentine and the interdigital flow fields [22]. Methods in former research to improve the distribution uniformity of reactive gases, namely changing the cross-section flow channel or adding block structure, or baffles, in the flow channel, have been investigated [23; 24; 25; 26; 27]. [PERSON] et al. built a fuel cell model with baffles in cathode flow channels to study the influence of the distribution and size of baffles on the performance of PEMFC, and found that the baffles in flow channels could improve the performance of PEMFC by enhancing the distribution uniformity of reactive gases [28]. To save time and calculation resources, a series of fuel cell models were designed, and surrogate models were trained by machine learning to optimize the fuel cell performance based on the chosen algorithm [29]. [PERSON] et al. made an Artificial Neural Network (ANN) model to predict the cell voltage consistency of a PEMFC [30]. [PERSON] et al. made a Radial Basis Function Neural Network (RBFNN) model of PEMFC to optimize the contact pressure of GDL [31]. [PERSON] et al.