Optimization And Control Strategies Of Circulating Aquaculture Equipment

Intensive Pond Aquaculture(IPA)is an important means to transform aquaculture from agricultural production to industrial production.Because the technology is relatively new and the implementation process is complex,at present,the assembly and operation of aquaculture equipment mostly rely on manual experience,lacking of systematic research on IPA technology.Concentrated discharge of aquaculture pollution is the main purpose of IPA.Due to the limitations of equipment power and aquaculture cost,the current sewage discharge rate is still relatively limited.In addition,compared with traditional aquaculture,the demand for power in IPA aquaculture is greatly increased.Because many farmers can not afford the sudden high cost of power,the promotion of IPA technology is hindered.To sum up,it is of great significance to control the power loss in the process of aquaculture.Aiming at the problem of insufficient sewage discharge rate and excessive power consumption,this paper studies the structure of aquaculture tank and the control of aeration equipment in IPA technology from two aspects: the deployment of aquaculture equipment and the operation of equipment.The main contents of this paper are as follows:According to the actual aquaculture environment and equipment characteristics,a reasonable physical model of aquaculture area is constructed,and the fluid situation is simulated.Firstly,the basic theory of fluid numerical simulation and the corresponding mechanical equation are introduced.Then,considering the particularity of multiphase flow generated during the operation of the actual system,the flow field with bubbles and solid particles is simulated by combining Euler and Lagrangian multiphase flow models and discrete element method.Finally,the convection-diffusion equation of dissolved oxygen(DO)is introduced to calculate the distribution of dissolved oxygen independently,and the results are post-processed to realize the visualization of simulation results.In order to solve the problem of insufficient sewage discharge rate under limited water flow,the bottom structure of aquaculture tank is designed and the structure parameters are determined to improve the pollution discharge efficiency from the level of optimizing the flow field structure.In order to complete the optimization,the flow structure under different equipment is simulated numerically,and the velocity distribution model based on data-driven is established.At the same time,according to the two different movement patterns of polluted particles in water and the flow situation in the aquaculture tank,the modified models of particle start-up and particle transport are established.On this basis,the multi-objective optimization method is used to find out the optimal structural parameters so that the startup and transport performance of the aquaculture tank can be optimized.Finally,the correctness of the optimized parameters is verified by simulation experiments.Aiming at the problem of excessive energy consumption of aeration equipment in aquaculture process,the deployment and control strategy of aeration equipment are optimized and designed from the point of view of reducing equipment power and aeration waste.Firstly,according to dissolved oxygen simulation results,the effects of equipment deployment parameters on aeration performance are studied,and an aeration performance model is constructed and a set of optimal equipment parameters are optimized.Furthermore,taking tilapia culture as an example,a dynamic model of dissolved oxygen concentration and fish body weight under aeration flow control is established,and the system control strategy is designed based on economic model predictive control(EMPC)theory.The simulation results show that the proposed aeration strategy can maximize the energy consumption of equipment while maintaining high growth level of fish.