不同供氢方式对X型转子发动机性能影响的仿真研究  

Performance Numerical Analysis of X-Type Rotary Engine under Different Hydrogen Supply Methods

作　　者：耿琪 王学德[1] 杨正浩 杜洋 何光宇[1] GENG Qi;WANG Xuede;YANG Zhenghao;DU Yang;HE Guangyu(Science and Technology on Plasma Dynamics Laboratory,Air Force Engineering University,Xi’an 710038,China;School of Mechanical Engineering,Xi’an Jiaotong University,Xi’an 710049,China)

机构地区：[1]空军工程大学等离子体动力学重点实验室,西安710038 [2]西安交通大学机械工程学院,西安710049

出　　处：《西安交通大学学报》2023年第2期78-89,共12页Journal of Xi'an Jiaotong University

基　　金：国家自然科学基金资助项目(61873351);装备预研重点实验室开放基金资助项目(6142202210201)。

摘　　要：为了进一步提升新型动力装置X型转子发动机的性能,采用掺氢燃烧的方式改善发动机的燃烧过程。利用数值仿真建立并验证了XMv3型转子机的掺氢CFD模型,选择了进气道掺氢和燃烧室直喷掺氢两种供氢方式进行对比,探究了掺氢对缸内流动、燃烧和排放过程的影响,揭示了掺氢比例以及不同供氢方式对缸内湍动能和涡度、自由基团、缸温和缸压以及CO和NO_(x)排放的影响规律。结果表明:在进气过程中,缸内形成了伴随着两个涡团的主流场,将气体带向燃烧室的两侧,充分混合空气与燃料,有利于燃烧过程;掺氢后,燃烧区域向燃烧室两侧狭缝扩展,改善了燃烧性能,且直喷掺氢的效果要明显优于气道掺氢的;同时,由于采取高当量比的燃烧策略和掺氢提高了缸内温度,分别使得CO和NO_(x)的排放量明显增加;相比未掺氢的情况,掺氢能量分数为5%时,气道掺氢和直喷掺氢的缸压峰值分别提高了16.71%和43.15%。本研究可为X型转子发动机供氢方式的设计提供参考依据。To further improve the performance of X-type rotary engine(XRE),a new-type power unit,hydrogen-blended combustion is adopted to enhance the engine’s combustion process.Firstly,by numerical simulation,a CFD model of the XMv3 engine with hydrogen-blending is established and verified.On this basis,two hydrogen supply modes,port injection(PI)at intake and direct injection(DI)at combustion chamber,are selected for comparison to investigate the influence of hydrogen-blending on in-cylinder flow,combustion and emission process,thus revealing effects of hydrogen contents and hydrogen supply modes on in-cylinder turbulent kinetic energy and vorticity,free radicals,in-cylinder temperature and pressure,as well as CO and NO_(x) emissions.The results show that a main flow field accompanied by two vortexes is formed in the cylinder during the intake process and the gas is brought to both sides of the combustion chamber for mixing with air and fuel,thus facilitating the combustion.Upon hydrogen-blending,the combustion area expands to the slits on both sides of the combustion chamber so that the combustion performance is improved.It is also shown that hydrogen DI yields better performance than hydrogen PI.Meanwhile,the combustion strategy with a high equivalent ratio and the increased in-cylinder temperature due to hydrogen-blending lead to significant increase of CO and NO_(x) emissions,respectively.Compared with combustion without hydrogen,the peak cylinder pressure is increased by 16.71%and 43.15%for PI and DI respectively with a hydrogen-blending energy fraction of 5%.This study provides a reference for the hydrogen supply design of XRE.

关 键 词：X型转子发动机 直喷掺氢 气道掺氢 燃烧 

分 类 号：TK45[动力工程及工程热物理—动力机械及工程]