nvPM采样输运系统损失因子计算与改进研究

Study on calculation and improvement of loss factor of nvPM sampling and transportation system

航空发动机排放的非挥发性颗粒物(nvPM)是大气污染的重要来源之一,对人体健康会造成一定的影响。在采样测量过程中会有一定量的损失,为能够更便捷高效地计算排放损失校正因子,该文结合CFM56-7B26/3型发动机排放数据和美国汽车工程师协会(SAE)排放测量校正因子建议标准改变计算流程,开发出一套计算工具。结果显示,新计算工具计算的数量浓度排放校正因子与发动机推力呈负相关,在推力为100%的额定推力下,数量校正因子最小,在推力为3%(慢车状态)处最大,与原方法结果趋势相同,且最大绝对误差为6.81,最小为0.64;质量校正因子也与发动机推力呈负相关,与原方法结果最大绝对误差为0.14,最小为0.007。新计算工具能够更好地与实际数据和推力相联系,在与原方法差异不大的情况下,能够实现更高效便捷的损失校正因子计算。

Non-volatile particulate matter(nvPM) emitted by aircraft engines is one of the important sources of air pollution, which will have a certain impact on human health. There will be a certain amount of loss in the sampling measurement process. In order to more easily and efficiently calculate the emission loss correction factor, this article combines the CFM56-7 B26/3 engine emission data and the SAE emission measurement correction factor recommended standard changed the calculation process and developed a set of calculation tools. The results show that the number concentration emission correction factor calculated by the new calculation tool is negatively correlated with the engine thrust. At a rated thrust of 100% thrust, the number correction factor is the smallest and the thrust is 3%(idle). The trend is the same as that of the original method,and the maximum absolute error is 6.81, the minimum is 0.64;the mass correction factor is also negatively correlated with the engine thrust. The maximum absolute error is 0.14 and the minimum is 0.007. The results show that the new calculation tool can better link with the actual data and thrust, and can achieve more efficient and convenient loss correction factor calculation under the condition of not much difference from the original method.