Fig. 1. Schematic diagram of smoke shielding experiment
Fig. 2. Layout diagram of experiment setup
Fig. 3. Mid-infrared obscuring ratio of the tested particles vs time
Fig. 4. Time dependence of the far infrared obscuring ratio of the tested particles
Fig. 5. Mid-infrared obscuring ratio of aluminum powder at different target and background temperatures
Fig. 6. Far infrared obscuring ratio of aluminum powder at different background temperatures
Parameters | Mid-infrared
(3.7-4.8 μm)
| Far-infrared
(7.5-14 μm)
| Graphite(200 meshes) | 0.63 | 0.64 | Graphite(1 000 meshes) | 1.02 | 1.01 | Graphite(5 000 meshes) | 1.28 | 1.23 | Graphite(10 000 meshes) | 1.54 | 1.43 | Aluminum(1 000 meshes) | 1.78 | 2.02 |
|
Table 1. Testing result of mass extinction coefficient of the different particles
λ/μm
| Graphite | | Aluminum | n | k | n | k | 3 | 2.84 | 2.35 | | 4.9 | 29.82 | 4 | 3.29 | 2.67 | 6.77 | 38.68 | 5 | 3.65 | 2.94 | 9.15 | 47.2 | 7 | 4.29 | 3.23 | 14.44 | 63.75 | 8 | 4.49 | 3.36 | 17.68 | 71.77 | 9 | 4.66 | 3.52 | 21.36 | 79.24 | 10 | 4.84 | 3.67 | 25.01 | 85.97 | 11 | 5 | 3.81 | 28.58 | 92.43 | 12 | 5.14 | 3.95 | 32.11 | 98.76 | 13 | 5.26 | 4.11 | 35.68 | 104.63 | 14 | 5.37 | 4.26 | 39.15 | 110.19 |
|
Table 2. IR refractive index of graphite and aluminum(n+ik)
Experimental conditions | MECs/m2·g-1 | Mid-IR
(3.7-4.8 μm)
| Far-IR
(7.5-14 μm)
| Case (1) | Tt:100 ℃Tb:20 ℃
| 1.78 | 2.02 | Case (2) | Tt:100 ℃Tb:60 ℃
| 1.76 | 2.01 | Case (3) | Tt:100 ℃Tb:none
| 1.29 | 0.67 | Case (4) | Tt:60 ℃Tb:20 ℃
| 1.82 | 1.98 | Case (5) | Tt:60 ℃Tb:none
| 0.79 | 0.37 |
|
Table 3. Mass extinction coefficient of aluminum powder at different background temperatures