Research on oxygen transfer in an aerated flow with emergent vegetation

In the case of increasingly serious river pollution worldwide, aeration in channels is an effective way to solve water pollution. However, traditional aeration research is aimed mainly at nonvegetated channels, and there is relatively little research in vegetated channels. Aeration contributes to the absorption of pollutants by vegeta-tion, so studying the mass transfer of dissolved oxygen in vegetated channels is of great significance. This paper innovatively studies the variation law and formula of the oxygen mass transfer coefficient in vegetated channels through an experiment and theoretical analysis. Through flume experiments, this study examines the bubble size and oxygen transfer coefficient under different vegetation densities and establishes a formula to simulate the oxygen transfer coefficient under different vegetation densities. The results show that vegetation has little effect on bubble diameter, and the main effect on bubble diameter is the aeration rate. The existence of vegetation significantly increases the mass transfer of oxygen, and the higher the vegetation density is, the greater the oxygen transfer coefficient transfer is. At the same time, a formula predicting the oxygen transfer coefficient is proven, and the simulation results are good, in which the coefficient of determination (R2) was 0.9535 and the mean absolute error (MAE) reached 0.0857. This study provides a theoretical basis for the selection and layout of aeration systems in vegetated channels.