制备生物柴油中超声空化过程的研究

建立了超声波辅助制备生物柴油中空化气泡运动的动力学模型,采用MATLAB对模型方程进行数值模拟,探讨超声频率、声压幅值、空化泡的初始半径和环境压力对空化泡运动的影响.模拟结果表明,随着超声波频率的增加,空化效应减弱;超声声压较小时,超声波空化为稳态空化过程,随着声压的增加,空化气泡半径变化幅度增加,空化气泡所带来的空化效应必然增加;气泡的原始半径为超声波频率对应的共振尺寸时,空化情况最为激烈,声化效果最好;环境压力变化时,气泡运动的振幅差别不大.经分析得到提高生物柴油产率的较佳条件,即较低频率、较大声压幅值、气泡直径为共振尺寸、普通大气压.该研究可为超声在制备生物柴油中的应用提供基础理论依据.

Study on ultrasonic cavitation of biodiesel production

The model to describe bubble dynamic motion of ultrasonic-assisted biodiesel production was presented and the numerical simulation of the model equation was carried out through MATLAB.The effects of the factors such as ultrasonic frequency,sound pressure and initial radius of the bubble as well as environment pressure on the bubble motion and cavitation were investigated.The results indicated that cavitation effect became weak with the increase of ultrasonic frequency.Ultrasonic cavitation was steady-state cavitation process when the ultrasonic sound pressure was lower,but the bubble motion and cavitation were strengthened with ultrasonic sound pressure increasing.Cavitation effect was in the best condition when initial radius of the bubble corresponded to resonance size.In addition,amplitude of the bubble fluctuated mildly when environmental pressure changed little.Very good etching condition to improve biodiesel production was obtained,low frequency,larger amplitude sound pressure,the bubble resonance radius and normal atmosphere.This work provides a very important theory basis for the application of ultrasound to biodiesel production.