FIRE IN NORTHEAST CHINA FORESTS

Fire plays an important role in Northeast China forests. The occurrence of fires is closely related to the environmental characteristics. High temperature, drought, and strong wind in spring ( March to July ) and autumn ( September to November ) are common fire climatic characteristics in Northeast China. Based on the chemical and physical characters of fuels, fuel quantity distribution, sites as well as fire potential behaviour, fourteen fuel types have been classified in Northeast China Forest area. The fire adaptation of several main tree species has been also analysed in this paper. These species are widely distributed and of great economic significance in Northeast China. Fire use is paid much more attention recently. Fire have been employed in many silviculture practice such as firclinc creation, fuels reduction and seed bed preparation in Northeast China

同轴分级低排放燃烧室头部适应性设计研究

本文以一种天然气低排放同轴分级燃烧室头部为对象,在总体结构不变的前提下,将其按照等马赫数准则缩放分别装配到西气东输型燃气轮机、发电用重型燃气轮机及航改型燃气轮机燃烧室上。采用数值模拟的方式探究提高头部适应性的方法,结果表明:在合理的范围内,降低中心两级当量比,可以在一定程度上提高燃烧室的燃烧效率,并且效率达标后,在保证值班级起到稳定火焰作用的前提下,通过降低值班级当量比可以实现降低NO_(x)和CO排放的目的。通过上述方法,达到西气东输型、发电用重型、航改型燃气轮机燃烧室效率≥99%、NO_(x)排放体积浓度≤25×10^(-6)、CO排放体积浓度≤50×10^(-6)的技术指标。