为了解决化石燃料储备不足与环境污染问题，生物质燃料作为石油替代能源得到大力提倡，如何合理地将化石燃料替换为生物质燃料且维持设备正常运行成为工程上亟待解决的问题。本文采用CFD软件研究了车载5 kW生物乙醇微型燃烧室的燃烧特性，对比分析了不同功率（0.5~5 kW）和出口温度（840~960 K）时的回流区长度与宽度、回流量、出口温度分布系数（OTDF）、出口NO体积分数等特征参数。结果表明：随着出口温度升高，回流区长度逐渐缩短，回流量减少，出口温度均匀性逐渐变差，出口NO体积分数明显增加；随着燃烧室功率增大，回流区长度变长，回流量增加，OTDF先增大后减小，NO体积分数随着功率的降低而显著升高，最大值出现在1 kW时，达到满负荷时的7倍。因此，为了实现稳定燃烧和减少污染物排放，该乙醇微型燃烧室应在较高的空燃比（即较低的出口温度）和功率下运行。

To solve problems of fossil fuel shortage and environmental pollution, biomass fuels are strongly advocated as an alternative energy source to petroleum. Therefore, how to reasonably replace fossil fuels with biomass fuels and maintain normal operation of equipment has become an urgent problem in engineering. In this paper, CFD software is used to study the combustion characteristics of a vehiclemounted 5 kW bioethanol microcombustion chamber. The characteristic parameters such as the length and width of the recirculation zone, the recirculation mass flow rate, the outlet temperature distribution factor (OTDF) and the outlet NO volume fraction were compared and analyzed at different powers (0.5 to 5 kW) and average outlet temperatures (840 to 960 K). The results show that as the average outlet temperature increases, the length of the recirculation zone gradually shortens, the recirculation mass flow rate decreases, the uniformity of the outlet temperature gradually deteriorates, and the outlet NO volume fraction increases significantly; as the power of the combustion chamber increases, the length of the recirculation zone becomes longer, the recirculation mass flow rate increases, and OTDF first increases and then decreases. The NO volume fraction increases significantly at lower power, and the maximum value appears at 1 kW, which is 7 times that of full load. Therefore, in order to ensure stable combustion and reduce pollutant emissions, the ethanol microcombustor should be operated at a higher airfuel ratio (i.e. lower outlet temperature) and power.

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