Research Of Double-Layer Composite Submarine Surface Aeration Machine

As a kind of important sewage disposal equipment, the aerator has been widely promoted and used. Although there are many types of aeration machine on the market at present, there are some disadvantages of the existing aeration machine, for inverted umbrella aerators, deep aeration can not be carried out, aeration efficiency is low, installation is not convenient; for submersible aerators, the aeration can only be used for special sewage treatment pond. Therefore, under the present situation, it has important and realistic meaning to carry on the optimization design of the aerator by analyzing the deficiency of existing products in the market, studying on the aeration mechanism and structure optimization of existing products. Based on the characteristics of commonly used aeration machine on the market in particular inverted umbrella aerators and submersible aerators, at the same time taking into account factors about the aeration equipment such as the reliability, the economical performance, the advancement of technology, the stability. The thesis presents a double-layer aeration mechanism, designs a double-layer composite submarine surface aeration machine, makes the experimental prototype of double-layer composite submarine surface aeration machine. The aerator combines with the advantages of submersible aerators and inverted umbrella aerators, has a broad market prospects, meets the new needs of environmental protection.First of all, based on theoretical basis of aerators innovative design and design requirements of aerators, by researching and analyzing the principle and structure of commonly used types of aeration machine on the market, extracts the core functions of the aerator——dissolved oxygen, carries out a functional decomposition of dissolved oxygen, four sub functions are obtained, they are inflatable function, water propulsion function, gas-water diversion function, gas-water mixture function, and the principle of the above four sub functions are analyzed, on the basis of this, the preliminary design schemes are selected, evaluated, summarized and determined, the relative optimal design scheme of the aeration machine is obtained.Secondly, based on the relative optimal design scheme, extracts the main equipment of the aeration machine: gas supply device, water propulsion device, gas-water mixture device, gas-water diversion device, presents a hollow spindle inflatable, inverted umbrella coaxial double-propeller plug flow and secondary aeration structures, the prototype of the double-layer composite submarine surface aeration machine is drawn, then the structure and working principle of aeration machine are introduced in detail.And then, based on computational fluid dynamics, fluent numerical simulations about the aerated flow field in the single work of inverted umbrella impeller, in the single work of plug flow and in the work of inverted umbrella impeller with plug flow are respectively carried, the reliability of the design plan is verified, On the basis of them, fluent numerical simulations about the aerated flow field in the work of inverted umbrella impeller with plug flow at different heights are carried, in order to find out the relative optimal height difference.At last, combine the three-dimensional prototype of the double-layer composite submarine surface aeration machine with iteration convergence results, based on the working principle of the structure, structural features and innovations, making the experimental prototype and the simple model, and drawing the engineering drawings of the important parts of the structure.All the works included in this thesis will be the foundation work for further research on the aeration machine, numerical simulation results show that: the double-layer composite submarine surface aeration machine has the advantage of gas-water mixture fully, large service area, short water cycle time, achieves secondary aeration of shallow and deep water, improves the aeration efficiency, plays a positive role in developing new products for the future, has very important and realistic meaning.