船舶废气排放扩散模拟计算方法研究

基于船舶AIS数据的船舶废气排放评估计算模型,以高斯烟团扩散模型为核心,结合船舶航行和排放特征,构建移动船舶源排放烟团扩散模型。利用控制变量法,在其他变量参数相同条件下,分别设定不同风向、不同大气稳定度、不同高程平面,仿真模拟航行状态下的船舶排放烟团扩散至空间环境中的质量浓度分布情况,分析船舶在不同环境参数下的扩散特征。结果表明,仿真模拟结果与实际气体空间质量浓度分布情况相符。通过在深圳市盐田港区布设船舶废气排放岸基固定嗅探监测设备,对港区进、离港和过往船舶进行大气污染物排放组分(SO2、CO2、NO、NO2)全天在线实时监测,以SO2作为试验样本气体,船舶排放的SO2排放至监测站的模拟质量浓度与实际监测质量浓度标准误差为19.81%,在合理的误差范围内,验证了船舶废气排放扩散模拟计算方法的科学有效性。

Improved calculation model for ship exhaust emission dispersion

The given paper is devoted to presenting an improved calculation model of the ship exhaust emission dispersion to supervise and regulate the ship transportation and navigation exhaust emissions more truthfully.As a matter of fact,ship emission standard involve one of the characteristic features in relation to its mobility,dispersibility,randomness and monitoring control.In the previous studies,the ship exhaust emission source used to be regarded as the stationary source emission one.But we have first of all set up a coordinate transformation relation model between the geodetic coordinate and the wind direction coordinate,while taking into account the influential factors of the wind,wave and current to build such an emission dispersion model of the mobile ship,based on the features of its navigation,emissions and diffusion.However,the former model is used as the calculation model of the ship exhaust emissions based on the AIS and the ship functional activity data,with the Gaussian Puff Dispersion Model(GPDM)taken as its central part of the given model.Therefore,the model can be adopted to calculate the ship emission diffuse into the atmospheric environment with its gas content rate in any wind directions and in any temperal moments.Thus,analyzing the features of the ship emission plume dispersion in any different environmental parameters under the different control effects,the simulation of the spatial distribution of the ship emission puff dispersion in the above said 3 diffusion scenarios in the different wind directions,the wind velocity and elevation,as well as the other parameters,would be taken as permanent and unchanged factors.The simulation results can be proven well in accord with the actual distributions of the gaseous pollutants.The gaseous pollutants sniffer monitoring system can be set up in Yantian Port,Shenzhen,to perform the on-line monitoring ship exhaust emissions(SO2/CO2/NO/NO2)throughout the daily terms.It can also provide the concentration rate information of the ship emission plume spreading and scattering to the nearby other-involved monitoring stations.Thus,finally,when choosing 2 ships as the case study sample,and the SO2 emission by the ship as the test gas sample to verify the model,the calculation error rate between the simulation data and the real monitoring data may turn out merely 19.81%,which implies that the error rate gap should be put into the reasonable category.It also implies that the dispersion model of the mobile ship exhaust emissions proves to be scientific as well as applicable.