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刚性壁面附近传质传热双气泡的声空化效应

Acoustic cavitation effect of double bubbles with mass and heat transfer near a Rigid Wall

  • 摘要: 为探究气泡的传质传热属性对刚性壁面附近双气泡空化效应的影响,利用修正的Keller-Miksis方程与Noble-Abel-Stiffend-Gas状态方程相结合的新模型,研究了超声作用下刚性壁面附近的具有传质传热属性双气泡的空化效应,并与没有传质传热属性双气泡的空化效应进行了比较。结果表明,无论双气泡之间有无耦合作用,有传质传热的大小气泡的最大膨胀半径都变大、溃灭时间都变长,大小气泡随壁面距离变化压缩比都变小;对比双气泡溃灭速度随壁面距离的变化发现,无论双气泡之间有无耦合作用,有传质传热的小气泡的溃灭速度大于没有传质传热的小气泡的溃灭速度,而有传质传热的大气泡的溃灭速度小于没有传质传热的大气泡的溃灭速度;对比双气泡射流速度随归一化距离的变化发现,有和没有传质传热的两种气泡射流速度的差别较小,表明气泡的传质传热性对射流速度的影响较小。对比双气泡的泡内温度随壁面距离的变化发现,无论双气泡之间有无耦合作用,有传质传热的大小气泡的泡内温度都低于没有传质传热的大小气泡的泡内温度。

     

    Abstract: To investigate the influence of mass and heat transfer properties of bubbles on the acoustic cavitation effect of double bubbles near a rigid wall, a novel model combining the modified Keller-Miksis equation with the Noble-Abel-Stiffened-Gas state equation is used to study the cavitation effect of double bubbles with mass and heat transfer properties near a rigid wall under ultrasonic. The results are compared with the caviation effect of double bubbles without mass and heat trasfer propeties. The results indicate that, regardless of the coupling effect between the double bubbles, the maximum expansion radii of both large and small bubbles with mass and heat transfer increase, their collapse times prolong, and the compression ratios of both large and small bubbles decrease as wall distance varies. By inspecting the variation of the collapse velocity of the double bubbles with wall distance, it is found that regardless of the coupling effect between the double bubbles, the collapse velocity of the small bubble with mass and heat transfer is greater than that of the small bubble without mass and heat transfer, while the collapse velocity of the large bubble with mass and heat transfer is smaller than that of the large bubble without mass and heat transfer. By examining the variation of the jet velocity of the double bubbles with normalized distance, it is revealed that the disparity in the jet velocities of the two types of bubbles (with and without mass and heat transfer) is minor, suggesting that the mass and heat transfer properties of the bubbles have a negligible influence on the jet velocity. By observing the variation of the internal temperature of the double bubbles with wall distance, it is discovered that, regardless of the coupling effect between the double bubbles, the internal temperatures of both large and small bubbles with mass and heat transfer are lower than those of the large and small bubbles without mass and heat transfer.

     

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