Aeration is an important factor affecting the biological aeration filter.With a set of experiment device specially designed for the purpose,and the particle image velocimetry technique,the velocity field of the gas-liquid two-phase flow is studied under different conditions.The various simulated aeration states were actually applied to the experimental device of sewage treatment,and the results of the numerical simulation were verified.The final experimental results indicate that the most efficient state occurs when the ratio of water in aeration tank h / w =1,the diameter of capillary tubes d=0.6mm and the velocity of bubbles v=0.3m/s.
Particle Image Velocimetry (PIV) technique was employed to study experimentally gas-liquid two-phase flow in an aeration tank. In terms of the PIV principles, an algorithm of PIV based on the Fast Fourier Transformation (FFT) was worked out. The PIV program was developed and verified, and then was used to measure three kinds of states in the testing device. The program was also used to calculate and analyze the related parameters. The experimental data indicate that the bubbles in testing device have the longest resident time and stronger turbulent intensity for the gas-liquid two-phase flow in a special case (Case 3), resulting in great increase of the oxygen transferring speed and efficiency, whereby providing the basis for the selection design of aeration tank.
