Thermal infrared emission-transmission measurements in flames from a cylindrical forest fuel burner
Thermal infrared emission-transmission measurements in flames from a cylindrical forest fuel burner
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DOI：
10.1071/wf06043
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发表时间：
2007-01-01
影响因子：
3.1
通讯作者：
de Castro, Antonio J.
中科院分区：
文献类型：
--
作者：
Dupuy, Jean-Luc;Vachet, Philippe;de Castro, Antonio J.
我们描述了使用热红外摄像机（7.5-13 μ m）在圆柱形森林燃料燃烧器火焰的不同高度进行的发射透射测量。森林燃料燃烧器是由一个圆柱形的金属丝网篮子制成的，篮子里装满了森林燃料（松针），在篮子的底部点燃。采用三种直径的吊篮（20、28、40 cm）。根据筐的重量和燃料的燃烧热计算，热释放率在50至170kW之间，火焰高度在1至2米之间。该发射传输装置允许测定火焰的透射率和辐射温度。我们表明，在相机的光谱范围内，辐射主要是煤烟，但燃烧的气体产物的辐射也不容忽视。利用米氏理论的瑞利极限，我们从测量中推断出一些平均体积分数的烟灰，在火焰持续区域达到6.8 x 10（-6）的峰值。然后根据标准方法计算了烟尘燃烧火焰的总消光系数和总发射率。测量到的透射率、烟尘体积分数、总消光系数和总发射率与归一化测量高度Z成正比，归一化测量高度Z定义为测量高度与火焰高度之比（0.25 < Z < 1.6）。
We describe emission-transmission measurements performed at different heights in a flame from a cylindrical forest fuel burner, using a camera operating in the thermal infrared (7.5-13 mu m). The forest fuel burner was made of a cylindrical wire mesh basket filled with a forest fuel (Pinus pinaster needles), which was ignited at the base of the basket. Three diameters of basket were used (20, 28 and 40 cm). Heat release rates, as calculated from weighing of the basket and heat of combustion of the fuel, ranged between 50 and 170kW and flame heights ranged between 1 and 2m. The emission transmission device allows the determination of the transmittance of the flame and of a radiometric temperature. We show that radiation was dominated by soot in the spectral range of the camera, but that radiation from gaseous products of the combustion was not negligible. Using the Mie theory in its Rayleigh limit, we deduced some average volume fractions of soot from the measurements, which peaked at 6.8 x 10(-6) in the persistent region of the flame. Then the total extinction coefficient and the total emissivity of the flame due to soot were calculated according to a standard method. Measured transmittance, soot volume fraction, total extinction coefficient and total emissivity were found to scale with the normalised height of measurement Z, defined as the ratio of the height of measurement to the height of the flame (0.25 < Z < 1.6).