• Infrared and Laser Engineering
  • Vol. 49, Issue 7, 20201021 (2020)
Schematic diagram of smoke shielding experiment
Fig. 1. Schematic diagram of smoke shielding experiment
Layout diagram of experiment setup
Fig. 2. Layout diagram of experiment setup
Mid-infrared obscuring ratio of the tested particles vs time
Fig. 3. Mid-infrared obscuring ratio of the tested particles vs time
Time dependence of the far infrared obscuring ratio of the tested particles
Fig. 4. Time dependence of the far infrared obscuring ratio of the tested particles
Mid-infrared obscuring ratio of aluminum powder at different target and background temperatures
Fig. 5. Mid-infrared obscuring ratio of aluminum powder at different target and background temperatures
Far infrared obscuring ratio of aluminum powder at different background temperatures
Fig. 6. Far infrared obscuring ratio of aluminum powder at different background temperatures
ParametersMid-infrared (3.7-4.8 μm) Far-infrared (7.5-14 μm)
Graphite(200 meshes)0.630.64
Graphite(1 000 meshes)1.021.01
Graphite(5 000 meshes)1.281.23
Graphite(10 000 meshes)1.541.43
Aluminum(1 000 meshes)1.782.02
Table 1. Testing result of mass extinction coefficient of the different particles
λ/μm GraphiteAluminum
nknk
32.842.354.929.82
43.292.676.7738.68
53.652.949.1547.2
74.293.2314.4463.75
84.493.3617.6871.77
94.663.5221.3679.24
104.843.6725.0185.97
1153.8128.5892.43
125.143.9532.1198.76
135.264.1135.68104.63
145.374.2639.15110.19
Table 2. IR refractive index of graphite and aluminum(n+ik
Experimental conditionsMECs/m2·g-1
Mid-IR (3.7-4.8 μm) Far-IR (7.5-14 μm)
Case (1)Tt:100 ℃Tb:20 ℃ 1.782.02
Case (2)Tt:100 ℃Tb:60 ℃ 1.762.01
Case (3)Tt:100 ℃Tb:none 1.290.67
Case (4)Tt:60 ℃Tb:20 ℃ 1.821.98
Case (5)Tt:60 ℃Tb:none 0.790.37
Table 3. Mass extinction coefficient of aluminum powder at different background temperatures