纳米铁粉燃烧特性研究

通过对粒径为50,100,500和20×10~3nm铁粉的比表面积实验(BET法)、燃烧热值实验和热分析实验,得到不同粒径铁粉的表面微观结构、燃烧热值和失重曲线,分析粒径对比表面积、燃烧热值的影响,研究不同粒径铁粉在10,20,30和40 K/min升温速率下的燃烧特性参数和动力学参数.结果表明:粒径减小,铁粉比表面积和燃烧热值均增大,当粒径为50 nm时,燃烧热值最高,其值为6 792.1 J/g.粒径增大,着火点温度、最高燃烧速率对应温度、燃尽温度升高,燃尽时间延长;升温速率增大,相同粒径铁粉的着火温度、最大燃烧速率对应的温度和燃尽温度升高,纳米铁粉的最大燃烧速率增大,而微米铁粉的最大燃烧速率减小.随着粒径和升温速率的增大,活化能和指前因子都增大且存在互补偿效应.

Combustion Characteristics of Nano Iron Powders

The surface microstructure,heat of combustion and thermogravimetric(TG)curves of different size iron powders were obtained through BET,combustion and thermogravimetry experiments of iron powders of the size 50,100,500 and 20×10~3nm.The effects of the size on specific surface area and heat of combustion were analyzed.The combustion characteristic and kinetic parameters of different size iron powders at heating rate of 10,20,30 and 40 K/min were mainly studied.The results show that the specific surface area and heat of combustion are increased with the decrease of size,and the heat of combustion reaches the maximum value of 6 792.1 J/g when the size is 50 nm.As the size increases,the temperatures of ignition,maximum combustion rate and burnout are increased and burnout time is prolonged.As the heating rate increases,the ignition temperature,the temperature of maximum combustion rate and burnout temperature at the same size are increasing.Maximum combustion rate of nano iron powders is increased while that of micron iron powders is decreased.There is mutual compensation effect between activation energy and pre - exponential factor,and both are increased with the increase of size and heating rate.