本文選題：冷凍干燥 + 預(yù)凍��； 參考：《制冷學(xué)報》2017年02期

【摘要】：控制預(yù)凍階段的過冷度對冷凍干燥制品品質(zhì)的均一性以及后期干燥速率有重要影響。本文通過實驗和理論研究了主動降壓誘發(fā)過冷水成核過程中降壓速率、預(yù)冷溫度和終壓等因素對小瓶內(nèi)過冷水成核現(xiàn)象的影響。結(jié)果表明:常壓下解除過冷度范圍為9~17℃,而在降壓過程中解除過冷度范圍為8~11℃;在5~20 k Pa/s內(nèi)降壓速率對成核影響不大;在100~400 Pa內(nèi)終壓越低,檢測到的解除過冷度越低。計算分析表明,降壓過程中水體表面及附近區(qū)域達到的最低溫度可能是影響成核的關(guān)鍵因素。
[Abstract]:Controlling the degree of undercooling in the prefreezing stage has an important effect on the uniformity of the quality of freeze-dried products and the drying rate in the later stage. In this paper, the effects of pressure lowering rate, precooling temperature and final pressure on the phenomenon of supercooled water nucleation in a small bottle have been studied experimentally and theoretically. The results show that the range of undercooling at atmospheric pressure is 9 鈩，

本文編號：1790745