PEMFC全功率变流量喷射器流场特性研究

Study on flow field characteristics of PEMFC full power variable flow ejector

针对质子交换膜燃料电池全功率氢循环对喷射器变流量的需求,提出并设计了不同嵌套方式的四喷嘴喷射器,以实现不同工况下变流量性能。为研究不同嵌套方式喷射器的流场特性及其循环性能,采用计算流体力学方法对喷射器进行建模和分析。结果表明,部分嵌套喷射器的内部流场比全嵌套喷射器的内部流场稳定;当二次流压力和背压不变时,一次流压力从6 bar(1 bar=100 kPa)增加到10 bar,部分嵌套喷射器引射比先上升后下降,在压力为7 bar时存在最大值;而全嵌套喷射器引射比是下降的趋势,通过与实验数据的比较,部分嵌套喷射器具有更优的性能;最后通过多喷嘴PWM逻辑控制,实现了170 kW燃料电池全功率变流量拟线性调控性能,满足燃料电池在变功率运行下的氢循环需求。

This article proposes and designs a four-nozzle ejector with different nesting methods to meet the variable flow requirements of proton exchange membrane fuel cell full power hydrogen recirculation under different working conditions.The computational fluid dynamics method is used to study the internal flow field of the different nesting type four-nozzle ejectors and recycling performance.The results show that the internal flow field of partially nested ejector is more stable than that of the fully nested ejector.When the secondary flow pressure and back pressure remain constant,the entrainment ratio(ER)of partial nested ejector firstly rises and then decreases with the condition of the primary flow pressure increasing from 6 bar(1 bar=100 kPa)to 10 bar where the maximum ER is obtained at the primary flow of 7 bar.Through the comparison with the experimental data,the partial nested ejector has better performance than the fully nested ejector whose performance of ER declines gradually in the whole process.Finally,the full power variable flow linear regulation performance is realized through the multi-nozzle logic control to meet the requirements of fuel cell variable power operation for the hydrogen cycle ejector.