基于热力学模型的PEMFC用喷射器的设计

Design and performance test of subsonic ejector for proton exchange membrane fuel cell based on thermodynamic model

根据气体的热力学方程,结合流体流动的连续性和动量能量的守恒方程,建立了一种质子交换膜燃料电池用亚音速喷射器热力学模型。从燃料电池的操作条件出发,设计了引射流体饱和增湿和不增湿两种对比工况,通过模型计算得到了两种工况下工作流体标准体积流量与喷嘴喉部直径、混合室截面直径的关系。根据模型计算结果设计了3.5 kW电堆用亚音速喷射器,并通过实验测试了该喷射器的引射性能。研究表明通过模型指导设计的喷射器具有良好的引射性能,同时针对水蒸气对引射系数的影响提出摩尔回流比的概念,可以更好地评价喷射器在质子交换膜燃料电池上的可使用性。

A new thermodynamic mathematical model of subsonic ejector for proton exchange membrane fuel cell was deduced according to gas thermodynamic equation, fluid continuity, momentum conservation and kinetic conservation. Two instances, the entrained hydrogen with and without being humidified, were designed and the initial parameters based on the actual operation condition of PEMFC system were provided. The throat diameter and the mixing tube diameter were finally calculated by the ejector thermodynamic mathematical model. An ejector was manufactured for a 3.5 kW rated power PEMFC system based on the calculated result. Its entrainment ratio was tested through both the ejector performance test facility and the thermodynamic mathematical model, and the entrainment performance of the designed ejector was good. At the same time, the hydrogen mole recirculation ratio was advanced, which can represent the hydrogen fuel stoichiometdc ratio in the PEMFC stack.