基于P3-T3方法的飞机LTO阶段氮氧化物排放量计算与分析

Calculation and analysis of nitrogen oxide emission from airplane LTO stage based on P3-T3 method

飞机起飞着陆循环(LTO)阶段包含高推力的起飞和爬升阶段,具有排放强度高、排放特性不稳定的特点.同时,该阶段飞行高度低,尾气排放会直接影响机场周边人群.因此,本文依据机载快速存取记录器(QAR)数据中的低压转子转速等特征参数,对LTO进行精确的阶段划分.同时,建立发动机排放特性参数与推力关系模型,并使用P3-T3方法对国际民航组织公布的发动机各阶段排放指数进行修正,最终计算GE90-115B发动机某次LTO阶段的实际氮氧化物排放量.结果表明,该方法与国际民航组织推荐的标准LTO估算方法相比,总量相差约40%,与原有的BM2方法相比也存在一定差异.分析认为,这种依据QAR实际飞行数据并结合发动机排放特性参数的发动机排放量计算方法,可以更加真实地反映发动机性能对排放特性的影响,可很好地适用于具体航班氮氧化物排放量的精确估算,为近地面飞机排放评估乃至机场排放清单的编制提供更加准确的依据.

The airplane LTO(take-off landing cycle) phase includes high-thrust take-off and climb phase, which introduces high emission intensity and unstable emission characteristics. The exhaust emissions will directly affect the surrounding population due to the low flight altitude in this phase. Based on the low pressure rotor speed and other characteristic parameters in the quick access recorder(QAR) data, the LTO is accurately divided into several stages. Establishing the engine emission characteristic parameters and the thrust relationship model, using the P3-T3 method correct the emission index of each stage of the engine published by ICAO, and finally calculate the actual nitrogen oxide emission of the GE90-115 B engine in a certain LTO stage. The calculation result shows a total difference of around 40% compared with the standard LTO estimation method recommended by ICAO, which is also different from the existing BM2 method. According to the analysis, this kind of engine emission calculation method based on QAR actual flight data combined with engine emission characteristic parameters, can reflect the influence of engine performance on emission characteristics more accurately, as well as improving estimation of NOx emissions from specific flights. This method provides a more accurate basis for the assessment of NOx pollution in near-surface aircraft and the construction of airport emissions inventory.