Different modes of bubble migration near a vertical wall in pure water

摘要

The migration of deformable bubbles with different sizes near a vertical wall in pure water was experimentally studied by the dual-camera orthogonal shadow method. The key factors affecting the migration are discussed. It was found that the effect of size and initial distance on bubble migration is indirect. For bubbles of the same diameter (d_(eq)=3.10 mm), the same mode occurs when the initial distance (0.5≤L*≤3.5) is changed. When the initial distance (L*=0.5) is constant, the same mode appears for bubbles of different sizes (2.27 mm≤d_(eq)≤3.40 mm). Furthermore, different modes are found in the same initial distance (L*=0.5) and size (d_(eq)=3.10 mm). In fact, the migration mode is determined by the initial distance, Reynolds number and Weber number. The size and initial distance can influence the frequency of different modes. Considering a variety of factors, four basic migration modes are summarized. New correlations are proposed to predict bubble behavior in different modes near the wall. The kinematic and dynamic parameters of different modes are discussed. It is expected that the results can be helpful to predict the gas-liquid flow near a wall and to improve related heat and mass transfer process.