强化换热管内超声空化影响因素的数值研究

Numerical Simulation of Ultrasonic Cavitation Influence Factors in Enhanced Heat Transfer Tube

利用FLUENT软件对超声波空化效应的影响因素进行了数值模拟。采用二维管道，对比研究了不同长度处的声压及其汽合率后，得出结论：频率20kHz的超声波对圆管能够作用的最大长度在4．0～5．0m之间，最佳的空化长度为4．0m，当超过4．0m时由于超声波衰减严重，空化效果变差；当声强不断增大时，管内整体的汽含率却越来越小，此时的空化效果会变差。对于不同的管道类型，由于横纹管的几何结构更容易汽泡的产生，故而其超声空化效果也最佳。

Through making use of FLUENT software, the ultrasonic cavitation influence factors were simula- ted; and having two-dimensional pipe adopted to study both sound pressure and mass quality at different lengths were implemented to show that the maximum length of the circular tube effected by 20kHz ultrasonic wave stays between 4.0 - 5.0m and optimal cavitation length is 4.0m ; and when 4.0m is exceeded, the seri- ous ultrasonic attenuation can be seen together with poor cavitation effect; and the increasing sound intensity can make mass quality in the tube become lower and lower together with worse cavitation effect. Regarding va- rious pipes, the geometric structure of the transversely-ridged tube benefits the generation of steam bubbles and has optimal ultrasonic cavitation effect.