天然气作为直喷式天然气发动机重要的燃料，其喷射压力对发动机燃烧特性有重要影响。采用CFD软件研究了不同天然气喷射压力对船用柴油引燃天然气直喷发动机燃烧性能的影响。结果表明：天然气喷射压力越大，其滞燃期和着火持续期越短；总放热量少，其NOx排放越低，但HC排放越高，Soot和CO排放先低后高。喷射压力越高，速度动能越大，混合越均匀燃烧更充分。喷射结束速度衰减较快，不利于混合与燃烧。天然气喷射压力的研究有利于优化发动机工作性能。
The effect of natural gas injection pressure on the injection, combustion and emission performance of marine diesel-fueled natural gas direct injection engine was studied by CFD software. The results show that the higher the injection pressure, the shorter the ignition delay period, the faster the ignition, the shorter the ignition duration, the lower the heat release rate, the lower the total heat release, the lower the NOx emission, but the higher the HC emission, soot and CO emissions are high in the early and late stages of natural gas combustion. The higher the injection pressure of natural gas, the greater the kinetic energy of its jet velocity, the more uniform the mixing, the earlier the contact with diesel, and the more fully the combustion. The velocity of natural gas jet attenuates rapidly after the end of injection, which is disadvantageous to fuel mixing and combustion.
2021,43(10): 89-94 收稿日期：2020-11-30
DOI：10.3404/j.issn.1672-7649.2021.10.019
分类号：TK431
基金项目：国家自然科学基金资助项目(No.51876083)
作者简介：李玉兰(1980-),女,博士研究生,主要从事高压直喷天然气发动机研究
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