严裕, 娄钦. 大密度比双气泡在孔板结构微通道内上升行为的格子Boltzmann方法模拟[J]. 空气动力学学报, 2022, 40(3): 120−129. doi: 10.7638/kqdlxxb-2021.0354
引用本文: 严裕, 娄钦. 大密度比双气泡在孔板结构微通道内上升行为的格子Boltzmann方法模拟[J]. 空气动力学学报, 2022, 40(3): 120−129. doi: 10.7638/kqdlxxb-2021.0354
YAN Y, LOU Q. Lattice Boltzmann simulation of the rising process of double bubbles in a microchannel with orifice plates[J]. Acta Aerodynamica Sinica, 2022, 40(3): 120−129. doi: 10.7638/kqdlxxb-2021.0354
Citation: YAN Y, LOU Q. Lattice Boltzmann simulation of the rising process of double bubbles in a microchannel with orifice plates[J]. Acta Aerodynamica Sinica, 2022, 40(3): 120−129. doi: 10.7638/kqdlxxb-2021.0354

大密度比双气泡在孔板结构微通道内上升行为的格子Boltzmann方法模拟

Lattice Boltzmann simulation of the rising process of double bubbles in a microchannel with orifice plates

  • 摘要: 基于格子Boltzmann两相流大密度比模型模拟了孔板结构微通道内双气泡在浮力作用下的上升过程,主要研究 Eötvös数(Eo)、气泡相对大小、气泡之间的距离以及气泡和孔板间的距离对气泡变形、合并的动力学行为以及气泡上升速度和气泡剩余质量的运动特性的影响。研究发现,随着Eo数的增大,气泡在通过孔板通道时形变越严重,表现为上部气泡和下部气泡在合并过程中所夹带的液泡数量和质量同时增加,且气泡在通过通道的过程中会发生多次接触、合并与破裂;数值结果还表明,随着Eo数的增大,气泡达到顶端的时间增加而气泡穿过孔板的质量减小。另一方面,当上方气泡的尺寸大于下方气泡的尺寸时,两气泡在合并的过程中夹带的液泡数量更少,气泡穿过孔板时更迟缓但能够穿过孔板的气泡质量增多。此外,对于不同的气泡间距离和不同的气泡与孔板之间的距离,发现上下气泡之间的距离过大或者过小时,在气泡的合并过程中都不容易夹带液泡,且气泡穿过孔板的质量随着两气泡之间距离以及上方气泡与孔板之间距离的减小而增加。

     

    Abstract: Based on the lattice Boltzmann two-phase large-density-ratio model, the rising process of double bubbles in a microchannel with orifice plates under the buoyancy force is simulated. The effects of the Eötvös number, relative size of bubbles, distance between bubbles, and distance between the top bubble and the orifice plate on the dynamics of bubble regrading the deformation and merge, as well as on the kinematics such as the rising velocity and the remaining bubble mass are systematically studied. It is found that as the Eövös number increases, the bubble deforms increasingly obvious when passing through the orifice. Moreover, the number and mass of bubbles entrained between the two bubbles also increase and the bubbles will contact, merge, and break several times during passing through the channel. The results also show that the time for bubbles to reach the top of the channel increases but the mass of bubbles passing through the orifice decreases as the Eötvös number increases. On the other hand, when the size of the upper bubble is larger than that of the lower bubble, there will be less entrained bubbles. As a result, the bubbles are slower to pass the channel but the mass of bubbles that can pass through the orifice plate increases. In addition, it is found that the entrainment of bubbles is not obvious if the distance between upper and lower bubbles is too large or too small, and the mass of bubbles passing through the orifice plate increases with the decrease of the distance between two bubbles and the distance between the upper bubble and the orifice plate.

     

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