燃料电池氢循环喷射器性能分析与结构优化

喷射器以其体积小、无运动部件、不产生寄生能耗等一系列优点,正成为氢燃料电池氢气再循环的理想解决方案。但电堆变工况下喷射器的循环流体与供给流体的高度耦合特性致使其与电堆的匹配和优化难度较大。本文针对燃料电池变负载工况下喷射器引射流体压力与背压耦合变化的情况,采用计算流体力学(CFD)流体力学计算和实验相结合的方法,获取多组不同NXP值和工况条件下喷射器内部压力场和速度场,探究变工况下NXP对喷射器性能的影响的演变规律。结果表明,一次流压力的提升有助于提升喷射器循环性能,压力为4 bar时,在NXP=-15.6 mm时,引射比达到峰值2.43。同时,本文基于研究结果,采用数值解析获得变工况喷射器最优NXP的判定方法,结果有助于宽工况下喷射器与电堆的匹配设计与优化。

Performance analysis and structure optimization ofejector in PEMFC hydrogen cycle

The ejector has advantages of small size, no moving parts, no parasitie energy consumption, ete. It is becoming an idealsolution for hydrogen reeycling in hydrngen fuel eells. However, it is difficult to mateh and optimize the ejcector with the stack due to thehigh coupling between the ejector''s circulating fluid and the supply fuid. In this paper, the combination of computation fluid dynamic(CFD) calculation and experiment is used to obtain multiple sels of different nozzle exit position(NXP) and working conditions underthe eoupling change of ejector ejeetion fluid pressure and back pressure under fuel cell variable load conditions. The internal pressurefield and velocity field of the ejector explore the evolution of the influence of the NXP variable operating conditions on the ejectorperformance. Results show that the increase of primary flow pressure is helpful to improve performance of the ejector. When the primarypressure is 4 bar, the ejeetion ratio reaches a peak of 2.43 when NXP is -15.6 mm. Meanwhile, based on the research results, thispaper utilizes numerical analysis to achieve the optimal NXP judgment method of the ejector under variable working conditions, which ishelpful to the matching design and optimization of the ejector and the stack under wide working conditions.