Performance Optimization Of Marine Hydrogen Fuel Cell

Hydrogen is favored for its outstanding advantages such as high efficiency,cleanliness,and highest calorific value.It has become one of the key technologies to solve global energy shortage and environmental pollution problems.At present,the ship's power is dominated by a large number of internal combustion engines,and the noise and pollution are serious.The fuel cells using hydrogen and oxygen as the main fuels have outstanding advantages such as zero emission,low noise,high power density and fast start-up,and are very suitable for marine power.In order to gain a deeper understanding of the working performance and structural characteristics of hydrogen fuel cells and optimize them,the following work has mainly been done in this paper:Based on the reaction mechanism of the fuel cell,this paper established a three-dimensional steady-state single-cell model using COMSOL simulation software,and numerically simulates the established single-cell model from three aspects: physical parameters,geometric parameters,and operating parameters.The effects of physical parameters such as the porosity of the diffusion layer and the conductivity of the electrolyte membrane on the performance of the cell,as well as the influence of geometric parameters such as flow channel depth and the thickness of electrolyte membrane on the performance of the cell,and the effects of operating parameters such as pressure and reactant inlet flow rate on the cell performance were analyzed and optimized from the polarization curves and concentration distributions.At the same time,in order to further improve the overall performance of the hydrogen fuel cell,the traditional flow field channel is longer and the pressure drop in the flow channel is large,and it will need to consume more external pump energy and uneven gas distribution.This paper presents the proposed fuel cell flow field structures such as bionics leaf-type flow channels,lung-type flow channels,interdigital flow channels,and spiral flow channels have been mathematically modeled and numerically simulated.And the pressures,reactant flow rate,cathode oxygen distribution,and current density distribution in different flow channels were compared and analyzed.It has guiding significance and reference value for the optimization of fuel cell flow field plate structure.After a comparative analysis,this article draws the following conclusions:1)As the porosity of the gas diffusion layer increases,the internal mass transfer performance of the cell is continuously improved,which in turn helps to improve the overall performance of the cell,but the porosity of the diffusion layer is not as great as possible;when the conductivity of the electrolyte membrane is increased,the conductive proton conductivity of the membrane is enhanced,the ohmic polarization is reduced,the output current density of the cell is increased,and the output performance of the cell is improved.2)As the depth of the flow channel increased,it has little effect on improving performance of the cell at low current density,and performance of the cell slightly improved at high current density;as thickness of electrolyte membrane decreased,conductive proton resistance decreases,ohmic polarization decreases,current density increases,fuel cell output performance has improved significantly.3)Increased back pressure helps to increase the partial pressure of the reaction gas,increased the electromotive force of the fuel cell,and the output performance of the cell is effectively improved;the inlet flow velocity of the reactants increases,which accelerates the diffusion of the reaction gas to the reaction interface,and the electrochemical reaction rate increases,which greatly contributes to the improvement of the performance of the cell.4)The bionic leaf flow field and the interdigitated flow field in the four types of flow field structures have better overall performance in terms of pressure drop distribution,reactant flow rate,oxygen distribution,and current density distribution,but they need to be optimized to make the flow path throughout the activity.The area is evenly distributed for better gas distribution uniformity.