| As the municipal population increased, the sewage treatment requirements increased gradually. To meet the standard of discharge, Wastewater treatment plant (WWTP) improved the oxygen levels in wastewater by aeration, and to create an aerobic environment for biochemical decomposition. Micro-bubble generator is the hydraulic equipment that used in aeration steps in the process of sewage treatment. Compared with the blast, surface and jet aeration mode, the micro-bubble aeration has the characteristics of high oxygen utilization rate, Low energy consumption, low environmental pollution. Due to the lack of existing theories and design experience, the research of micro-bubble generator is in variable working conditions, but always has same equipment structure. To solve these problems, a new micro-bubble generator with combined threads is put forward in this thesis. The Research mainly focuses on theories and experiment.(1) The principle of micro-bubble generator is studied. The design parameters that effect generator’s performance are analyzed. Based on the existing theoretical guidance and similar equipment design experience, experiment platform of micro-bubble generator is made refers to the relevant design standards and pump design theory.(2) Set up the geometric model by using Workbench, the micro-bubble generator hydraulic and aeration performance are analyzed with Fluent.(3) The aeration performance of triangle thread, semicircular thread and the combination thread are studied in different vacuum degree by experiment platform of micro-bubble generator.There are results obtained from the research as follows:(1) The new type of micro-bubble generator has good aeration capacity. The hydraulic performance conforms to the traditional impeller pump’s throttling curve. After experimental verification, this new type of micro-bubble generator can be used in sewage aeration process.(2) Combined thread characteristic can be integrated with single thread pumping characteristics, Compared with single thread micro-bubble generator, the generator has the characteristics of high flexibility, easy disassembly, changing the rotor-stator combination according to different working conditions, and this device can be used in different viscosity transmission.(3) Compared with a single thread micro-bubble generator, combined thread micro-bubble generator’s efficiency is 15% higher. It also can reduce the energy use in sewage treatment. Its oscillatory air flow can improve the oxygen mass transfer in gas-liquid flow. |
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