多超声协同的溴化锂溶液空化气泡动力学特性

Study on Characteristics of the Cavitation Bubble Dynamics of Lithium Bromide Aqueous Solution With Multi-frequency Ultrasonic Interaction

超声空化有助于强化盐溶液沸腾传热过程。为改善溴化锂水溶液在真空条件下的发生效率,提出了多超声协同强化吸收式制冷系统的溴化锂水溶液发生过程方法。构建了多超声协同的气泡动力学数学模型,探讨了不同因素对溶液空化特性的影响。通过搭建超声波强化发生器内溶液传热过程的试验台,对理论结果进行了可行性验证。研究结果表明:多超声协同相比单振子对真空发生器内溶液空化特性的影响,具有更明显的强化作用:频率为25 kHz,总超声功率为60 W时,双超声振子和单超声振子的系统发生率较无超声时分别提高了10.26%和5.69%,超声强化传热效率随着溶液浓度的增加而减弱。

Ultrasonic cavitation can obviously enhance the boiling heat-transfer process of the salt solution.In order to improve the generating efficiency of lithium bromide aqueous solution in vacuum,the multi-frequency ultrasonic interaction on the lithium bromide aqueous solution heat-transfer enhancement in the generating process of the absorption refrigeration system is proposed in this paper.The mathematical model of lithium bromide aqueous solution bubble dynamics with the multi-frequency ultrasonic interaction is constructed and the effect of different influencing factors on the characteristics of solution cavitation bubble dynamics are discussed.To order to verify the feasibility of the theoretical results,the experiment system for the ultrasound enhancement heat-transfer process of the solution in the generator is built.The results indicate that:the multifrequency ultrasonic interaction has a more effect on the solution cavitation effect in the vacuum generator than that of the single-vibrator;under the ultrasonic frequency and total ultrasonic power of 25 kHz and 60 W,respectively,compared with the non-ultrasound system,the system generating efficiency of the double-ultrasonic vibrator and single-ultrasonic vibrator are increased by 10.26%and 5.69%,respectively.The efficiency of heat-transfer enhancement decreases with the rise of solution concentration.