为了研究超声强化亚临界CO₂萃取的机理,说明超声对亚临界CO₂萃取的传质强化效果,借助萃取动力学模型对实验数据进行了拟合,并通过超声空化阈值的理论计算,得到亚临界CO₂的空化阈值随温度和压力的变化,同时结合超声空化的验证实验,探讨了超声在亚临界CO₂中的空化情况.结果表明：动力学方程能够较好地拟合萃取实验结果,模型方程中有无超声的E∞和k值的差异也证实了超声对亚临界CO₂萃取有明显的传质强化效果;相对较高的温度和较低的压力更有利于超声空化效应的产生;亚临界CO₂在理论计算不可能出现超声空化的条件下同样存在空化效应,此现象尚无合理的解释;超声强化亚临界CO₂萃取的机理包括空化效应和强化传质.

In order to reveal the enhancement mechanism of subcritical CO₂ extraction by ultrasonic and describe the mass transfer enhanced with ultrasonic,some experiments were carried out and the data were fitted with the help of a kinetic extraction model.Then,the cavitations threshold at variable temperature and pressure were obtained based on theoretical calculation.Moreover,the cativation in the subcriticalCO₂ extraction enhanced by ultrasonic was investigated according to the results of the experiments.The results show that（1） the established kinetic model fits the extraction data well;（2） the difference in E∞ and k values between the extractions with and without ultrasonic enhancement also confirm the obvious enhancement effect of ultrasonic for the mass transfer in subcritical CO₂ extraction;（3） the occurrence of ultrasonic cavitation is rather easy at relatively high temperature and low pressure;（4） the cavitation occurs even under the conditions that cavitation is theoretically unavailable,for which there is no reasonable explanation;and（5） the enhancement is mainly due to the cavitation effect and the enhanced mass transfer.