Study On Combustion Characteristics Of Changbai Larix Gmelinii Cutover Land

This paper conducted a changbai larix gmelinii deforested combustion characteristic research,mainly studies the deforested leftovers spread fire behavior characteristic parameters in the process of combustion,heat release and the regularity of gas release.First set up the bed combustion experiment to study the changbai larix gmelinii deforested combustion characteristic.Is mainly studied in the process of fire spread,fire spread speed,temperature field forward retention time,fire intensity and flow field distribution and change of fuel moisture content,wind speed and slope,the above five indexes change rule under different conditions.Wind speed in 0?4 m/s,the moisture content at 8.6%?24.3%,the slope in the range of 5 °?15°changes,fire spread speed increases with increasing wind speed,slope,and decreases with increasing fuel moisture content.Bed combustion center line equidistant distribution of the temperature measuring point temperature change law of first increased and then reduced,the temperature change curve peak interval and spread has certain corresponding relationship;Fire on soil temperature decreases with the increase of soil depth,the influence of the same soil depth,cutting root is far away from the nearby cut root soil temperature is higher;Slope gradient and fuel moisture content increase will make fire forward residence time increases,and the wind speed increases,the retention time decreases,Fire intensity increases with increasing wind speed,slope,decreases with increasing fuel moisture content.Moisture content is constant,the slope increases,the same minimum and maximum pitot tube measured velocity will increase with the increase of slope.And when the slope is constant,the moisture content increases,the pitot tube measured velocity of the maximum and the minimum has no obvious change.The study of heat release and the regularity of gas release in is built according to the ISO 9705 standard full-size the combustion chamber,according to the principle of oxygen consumption study of different moisture content and heat release rate and total heat release in different wind speed change rule of felling and study O2,CO2,CO concentration change in the combustion process.When the moisture content increases,when the wind speed is constant,the burning fuel bed,in the process of spreading combustion heat release rate decreased,at the end of the total heat release quantity is decreased;And when the wind speed,moisture content is the same,in the process of combustion heat release rate increase,at the end of the total heat release quantity will increase.Change the fuel moisture content or size of wind speed,the experiment process of O2,CO2,CO concentration changes also follow certain rules.Moisture content increases,the combustion process of relatively high concentration of O2,CO2 concentration is smaller;Wind speed increases,the spread of?O2 concentration in the process of combustion is relatively smaller,but CO2 concentration increases.And the change of the CO concentration is more complex,the curves of test engineering of the CO concentration has significant characteristics,namely the present a clear bimodal curve shape,at the same time have a saddle between bimodal bottom is relatively stable stage,in general,the moisture content increases,the CO concentration increase;Wind speed increases,the concentration of smaller.