Study On Hydrostatic Settling Characteristics Of Aquaculture Source Water And Optimizing Jet-pipe Arrangement Form In Circular Tank

Water treatment technology runs through the whole process of aquaculture production,and it is an effective means to achieve energy conservation and emission reduction in aquaculture process,high yield and quality of aquaculture products.The research contents of this paper include the source water settlement in the early stage of aquaculture,the influence of jet-pipe arrangement form（jet angle and distance from the wall）on the hydrodynamic characteristics of aquaculture pond,and the application of response surface method to predict the optimal arrangement form.The research results are divided into the following aspects.（1）Through four static sedimentation experiments,it is found that the sedimentation characteristics of suspended solids are related to the initial suspended solids concentration and particle size distribution of water body;the particle size of suspended solids in Zhoushan offshore water belongs to the category of silt,and the concentration is stable at 50-60 mg/L after 12 hours of static sedimentation,so it is difficult to completely remove suspended solids by static sedimentation;the weighted average sedimentation velocity ranges from0.001 to 0.01 cm/s,Moreover,the concentration and velocity were fitted by logistic model.The research results are helpful to deepen the understanding of the sedimentation characteristics of industrial aquaculture source water in Zhoushan Island,and provide scientific guidance on how to reasonably determine the sedimentation time of source water in the sedimentation tank.（2）By numerical simulation method,setting two series of single factor tests（jet angle and distance from the wall）,the trend of hydrodynamic characteristic parameters(、₅₀and_（62）)and the velocity distribution and uniformity of the bottom,middle and top three sections are analyzed under the condition of changing arrangement form.The results show that the best hydrodynamic characteristic is obtained when the jet angle is 50°and the distance from the wall is 12.5 cm.（3）The response surface method was used to design the experiment,and the single factor test results were taken as the center value to establish the model to predict the optimal value.The experimental results show that²,²（adjustment）are more than 95%,²（prediction）is more than 88%.Compared with the experimental results,the model shows good consistency and prediction ability.The model predicts the optimal response value(_（62）)under the optimal arrangement form（the jet angle is 44.93°and the distance from the wall is 13.35 cm）was 70.06 mm/s.The experimental result is 71.02 mm/s,and the error is only1.35%.Considering the_（62）and₅₀,the optimal jet-pipe arrangement form is determined as follows:jet angle is 46°and the distance ratio from the wall（That is,the ratio of the distance from the wall d to the tank diameter D）is 0.14.