不同氢气喷孔直径对汽油掺氢X型转子发动机性能及污染物排放的影响  

Impact of Different Hydrogen Nozzle Diameters on Performance and Pollutant Emission of X-Type Rotary Engine

作　　者：张泽奇 杜洋 杨正浩 高旭[1] 何光宇 ZHANG Zeqi;DU Yang;YANG Zhenghao;GAO Xu;HE Guangyu(School of Mechanical Engineering,Xi’an Jiaotong University,Xi’an 710049,China;National Key Lab of Aerospace Power System and Plasma Technology,Air Force Engineering University,Xi’an 710038,China)

机构地区：[1]西安交通大学机械工程学院,西安710049 [2]空军工程大学航空动力系统与等离子体技术全国重点实验室,西安710038

出　　处：《西安交通大学学报》2024年第2期66-78,共13页Journal of Xi'an Jiaotong University

基　　金：中国博士后基金面上项目(2023M732761);陕西省自然科学基础研究计划资助项目(2023-JC-QN-0596);装备预研国防重点实验室开放基金资助项目(6142202210201)。

摘　　要：针对高效X型转子发动机汽油燃烧不充分的问题,提出了一种缸内直喷掺氢方法用于提升燃烧效率和发动机热力性能。建立了X型转子发动机三维CFD数值模型,通过缸压、放热率和功率实验数据验证了模型有效性,在喷氢总量、喷氢压力、喷氢开始时刻相同的条件下,分析了氢气缸内直喷且汽油预混时氢气喷孔直径对发动机缸内流动、燃烧、热力性能以及污染物排放特性的影响,并与纯汽油预混式发动机性能进行对比,揭示了缸内直喷掺氢方法的优越性。结果表明,在小氢气喷孔直径(2 mm)下,火焰传播比较均匀,且在燃烧室两侧狭缝中都有较大的对称的火焰,燃烧更加充分,发动机指示热效率达到了最高37.07%,较不喷氢和大氢气喷孔直径(4 mm)分别提高了10.23%和7.85%。与大氢气喷孔直径相比,虽然小氢气喷孔直径下NO x排放量上升了21.12%,但是碳氢化合物、碳烟排放量分别下降了79.08%和2.17%。小氢气喷孔直径(2 mm)为最优喷氢方案,研究为X型转子发动机的喷氢方案设计与优化提供了指导。Aiming at the issue that the combustion of gasoline in high-efficiency X-type rotary engine is insufficient,a method of cylinder hydrogen direct injection is proposed to improve the combustion efficiency and thermodynamic performance of the engine.The three-dimensional CFD numerical model of X-type rotary engine is established and validated via the experimental data of cylinder pressure,heat release rate and power.Under the same hydrogen injection total mass,pressure,and start time,the impact of hydrogen injection nozzle diameter on the in-cylinder flow,combustion,thermodynamic performance and pollutant emission of the engine when hydrogen in-cylinder direct injection and premixed gasoline are adopted.The advantages of hydrogen in-cylinder direct injection method are revealed by comparing with pure gasoline premixed engine.The results show that when the hydrogen injection nozzle diameter is small(2 mm),the flame propagation is more uniform,and relatively large symmetrical flames are found in the slits of both sides of combustion chamber,making the combustion more sufficient.The maximum indicated thermal efficiency of corresponding engine reaches of 37.07%,which is 10.23%and 7.85%higher than that of the engine without hydrogen injection and with a large hydrogen injection nozzle diameter(4 mm),respectively.In addition,compared with the large hydrogen injection nozzle diameter,although the NO x emissions increase by 21.12%when the hydrogen injection nozzle with small diameter is adopted,the HC and soot emissions decrease by 79.08%and 2.17%,respectively.Thus,the small hydrogen injection nozzle diameter(2 mm)is the optimal hydrogen injection strategy.This study provides guidelines for the design and optimization of the hydrogen injection strategy of X-type rotary engine.

关 键 词：转子发动机 氢气直喷 喷孔直径 污染物 热效率 

分 类 号：TK45[动力工程及工程热物理—动力机械及工程]