飞机LTO排放影响评估耦合模型研究与应用

民航飞机在LTO起降阶段的飞行中，发动机污染物排放的源强和空间位置是动态的.为准确定量评估其影响，构建了飞机LTO污染排放影响评估耦合模型.首先利用飞行动力学模型，模拟飞机LTO飞行轨迹，并获得轨迹中每一位置点的性能参数（实时燃油流量）；再通过排放计算模型，确定每一位置点的污染物排放量（源强）；在此基础上，基于拉格朗日烟团模型，针对飞机烟团排气特点进行修正，实现污染扩散模拟.最后采集了一架典型飞机在一个完整LTO飞行过程中的机载数据，结合实时气象参数，进行了实例应用研究.结果显示.在LTO过程中NO_x、SO₂、CO、PM和HC的平均排放速率分别为17.71、2.21、1.05、0.20和0.03g/s；飞机在起飞离地时刻，烟团扩散范围集中于跑道附近及侧向300m、纵向3000m范围内，NO_x地面最大浓度超过100mg/m³；当飞机爬升至混合层顶完成起飞时，地面污染物扩散至侧向1200m范围，NO_x浓度降至298.5μg/m³，依然较为严重，其他污染物地面浓度相对较低_.

A coupling model and its application on impact assessment of the aircraft emissions during LTO cycle

The pollutants emission rate and spatial location of engines are dynamic during the LTO cycle of civil aircraft. To quantify and analyze the impact accurately, the paper constructed an aircraft LTO emission impact assessment coupling model. The paper was carried out by simulating the LTO flight path of aircrafts, using aerodynamics model, to get performance parameters (real-time fuel flow) of each position within the path. It defined pollutants emission rates of each position, by applying the emission calculating model. Then, it calibrated the Lagrangian puff model for the emission characteristics of the airplane puff, and simulated pollutants dispersion. It collected airborne data of a typical aircraft during its whole LTO cycle, and carried out a real case study, referring to real-time meteorological parameters. The result showed that the average emission rate of NO_x, SO₂, CO, PM and HC were 17.71, 2.21, 1.05, 0.20 and 0.03g/s respectively during the LTO cycle. When the aircraft took-off, the scope of puff dispersion amassed on the runway and were within 300meters laterally and 3000meters longitudinally of it, and the maximum ground-level concentration of NO_x surpassed 100mg/m³. When the aircraft climbed up to the top of mixing layer, finishing the take-off, the pollutants expanded laterally to 1200m, and the ground-level concentration of NO_x, keeping severe, declined to 298.5μg/m³. while the concentrations of other pollutants were relatively lower.