超声波作用下液滴的冷却冻结规律

发布时间：2018-06-29 06:19

  本文选题：超声波 + 冻结　； 参考：《化工学报》2017年11期

【摘要】：超声波液体辅助冻结在食品、海水淡化及冰蓄冷等方面的应用得到了广泛关注。结合声场理论,在对液滴界面处热质传递分析的基础上,建立了超声波作用下的液滴冷却冻结数学模型,讨论了不同超声波频率、强度及作用时间对液滴界面处热质传递的影响,得到了超声波作用下液滴的冷却冻结规律。结果表明:超声波作用下界面处的传质系数随着超声波强度的增加而增大,但随超声波频率的增加而减小;在液滴冷却冻结过程中,质量传递与热量传递的方向相同,液滴的冷却冻结在超声波作用下得到了强化。在超声波频率为20000 Hz(强度为400W?m-2),经过相同的时间(60 s),超声波作用下的液滴温度比无超声作用的温度低2.0~2.5℃。研究将有助于深入理解超声波辅助冷却冻结机理,并为其工程应用提供了指导和参考。
[Abstract]:Ultrasonic liquid-assisted freezing has been widely used in food, seawater desalination and ice storage. Based on the theory of sound field and the analysis of heat and mass transfer at the interface of liquid droplet, a mathematical model of cooling and freezing of droplet under the action of ultrasonic wave is established, and the different ultrasonic frequencies are discussed. The effect of intensity and time on the heat and mass transfer at the interface of droplet was studied and the cooling and freezing law of droplet under ultrasonic wave was obtained. The results show that the mass transfer coefficient at the interface increases with the increase of ultrasonic intensity, but decreases with the increase of ultrasonic frequency, and the direction of mass transfer and heat transfer is the same in the freezing process of droplet cooling. The cooling of droplets was strengthened by ultrasonic wave. When the ultrasonic frequency is 20000 Hz (intensity is 400 W / m ~ (-2), the droplet temperature under the same time (60 s), ultrasonic wave) is 2. 0 鈩，

本文编号：2081190