Experimental study on the sediment effect on releasing process of supersaturated total dissolved gas
摘要
During its transportation over long distances,supersaturated Total Dissolved Gas(TDG) may lead to gas bubble disease or even heightened fish mortality.Because the sediment concentration is always high in spill flow in China,studying the releasing law of supersaturated TDG in sandy water is of great theoretical and practical value.In the experiment described in this paper,we designed three kinds of experimental conditions,including a static water column,stir-induced turbulent water and an open channel flow.For each experimental condition,the TDG release processes were monitored both in fresh water and sandy water.The dissipation coefficients were calculated and compared under different sedimentation levels.The results indicate that both sediment and turbulence intensity can increase the release speed of TDG.The higher the sediment concentration level and turbulence intensity are,the greater the dissipation coefficients are.This study can provide important guidance for determining dissipation coefficients in a TDG simulation model,and can serve as a reference in exploring mitigation measures of supersaturated TDG.