Infrared and Laser Engineering, Volume. 51, Issue 12, 20220180(2022)
Study on thermal characteristics of Dewar flexible shell structure for cryogenic optics
Figures & Tables(17)
Fig. 2. Detector irradiance from stray light from the window cap at 300 K and 200 K
Fig. 7. Schematic diagram of low temperature test of integrated detector Dewar coller assembly
Fig. 8. Refrigeration Capacity of Cryocooler under Different Operating Conditions
Fig. 9. Flow chart of sinusoidal and random vibration test of integrated detector dewarcoller assembly
Table 1. Design requirements
View tableView in ArticleTable 1. Design requirements
Items Design requirements (Dewar heat load 1 W@55 K@195 K) Temperature difference between vessel and window cap ≥18 K Thermal resistance of bellows （77 K） 800 K/W Random vibration condition 20-100 +3 dB/oct 100-600 0.01946 g2/Hz 600-2 000 -9 dB/oct
Table 2. Design parameters of bellows
View tableView in ArticleTable 2. Design parameters of bellows
Items Design parameters Items Design parameters Wall thickness/mm 0.1 Inside Vacuum Material/L 316 Outside Atmosphere Wave pitch/mm 0.85 Stroke/mm 4 Wave number 26 Shaft Ø30 Leak rate (He)/Torr·s−1 <1E-10 Setting direction Vertical Size 0.D.46×I.D.33 Shape V
Table 3. Materials and properties of each part of the model
View tableView in ArticleTable 3. Materials and properties of each part of the model
Name Material Density/kg·m−3 Elastic modulus/GPa Specific heat capacity/J·kg−1·K−1 Cylindrical shell 304 L 8050 200 409 Bellows 316 L 8050 200 409 Enclosure Kavar 8360 142 352
Table 4. Result of modal analysis
View tableView in ArticleTable 4. Result of modal analysis
Mode Frequency/Hz 1 450.5 2 469.13 3 562.14 4 1381.4 5 1398.8
Table 5. Thermal loads of Dewar
View tableView in ArticleTable 5. Thermal loads of Dewar
Cryocooler working condition Temperature of detector/K Solid heat leakage/mW Radiant heat leakage/mW Thermal loads of Dewar/mW Normal temperature condition (pulse tube @23 °C) 60 673 1000 1673 High temperature conditions (pulse 263 K, window cap 228 K) 60 456 306 762 55 471 305 776 Low temperature conditions (pulse 228 K, window cap 193 K) 60 375 169 544 55 387 170 557 50 404 171 575
Table 6. Determination of thermal resistance of bellows
View tableView in ArticleTable 6. Determination of thermal resistance of bellows
Q/W T1/K T2/K ∆T/K Thermal resistance/K·W−1 Theoretical thermal resistance/K·W−1 Deviation 0 74.45 153.5 79.05 0.101 77.6 193 115.4 1142.574 1 831 37%
Table 7. Low temperature test data of integrated detector dewarcoller assembly
View tableView in ArticleTable 7. Low temperature test data of integrated detector dewarcoller assembly
Cryocooler working condition Temperature of detector/K Dewar leakage heat/mW Detector power consumption /mW Total load/mW Temperature of window cap/K Temperature of Hot end bellows/K Temperature of Cold end bellows/K Cooler power consumption/Wac Insulation effect of bellows/K Normal temperature condition (Pulse tube @296 K) 60 1673 0 1673 296 296 296 99 High temperature conditions (pulse 263 K, window cap 228 K) 60 762 0 762 229.84 267.71 230.49 52.08 37.22 60 762 600 1362 225.5 265.81 226.7 69.06 39.11 55 776 600 1376 223.21 263.94 224.35 89.1 39.59 55 776 0 776 221.88 263.4 222.47 61.6 40.93 Low temperature conditions (pulse 228 K, window cap 193 K) 60 544 0 544 214.56 253.16 215.52 46.84 37.64 60 544 600 1144 194.08 241.87 195.7 60.77 46.17 55 557 600 1157 193.27 243.52 194.61 72.74 48.91 55 557 0 557 192.83 242.31 194.25 56.52 48.06 50 575 0 575 192.43 241.04 194.41 65.72 46.63 50 575 600 1175 192.1 241.48 193.2 94.94 48.28
Table 8. Comparison of data before and after mechanical test
View tableView in ArticleTable 8. Comparison of data before and after mechanical test
Refrigerator working condition Temperature of detector/K Before mechanical test After mechanical test Cooler power consumption/Wac Insulation effect of bellows/K Cooler power consumption/Wac Insulation effect of bellows/K High temperature conditions (pulse 263 K, window cap 228 K) 60 52.08 37.22 52.11 37.33 60 69.06 39.11 69.61 39.42 55 89.1 39.59 88.92 39.83 55 61.6 40.93 61.48 41.09 Low temperature conditions (pulse 228 K, window cap 193 K) 60 46.84 37.64 47.07 37.87 60 60.77 46.17 60.59 46.49 55 72.74 48.91 72.66 49.15 55 56.52 48.06 56.80 48.01 50 65.72 46.63 65.59 47.10 50 94.94 48.28 94.66 48.57
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Junlin Chen, Xiaokun Wang, Zhijiang Zeng, Haiyong Zhu, Peng Ji, Hanzhe Wang, Xingjian Hu. Study on thermal characteristics of Dewar flexible shell structure for cryogenic optics[J]. Infrared and Laser Engineering, 2022, 51(12): 20220180
Paper Information
Category: Infrared technology and application
Received: Mar. 14, 2022
Accepted: --
Published Online: Jan. 10, 2023
The Author Email: Wang Xiaokun (wxk-sitp@sitp.ac.cn), Zeng Zhijiang (Jonzeng@sitp.ac.cn)
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