CAJ | 학술논문

　　为了全面了解现有自清洗网式过滤器内部水流结构和特性，为进一步结构优化提供依据，该文采用Fluent(6.3)软件对其进行了全流场数值模拟。在分析过滤器结构及自清洗原理基础上，建立了过滤器内部流场的数学模型和自清洗系统的动网格模型，给出了过滤过程和自清洗过程计算区域和网格、以及进出口边界条件，对比分析了自清洗流量与进出口压力降关系模拟结果和试验结果。分析表明：模拟压降与实测压降符合较好，可以保证后续模拟结果的可靠性；在此基础上，对过滤过程内部流场进行了模拟，得到了水流流速、紊动能和压力的分布规律，分析了过滤器结构设计不足。运用动网格技术，对过滤器自清洗过程进行了数值模拟，通过流速、紊动能和压力分布等流场分析，指出了自清洗系统的不足，研究结果可为过滤器结构优化设计提供参考。
　　위료전면료해현유자청세망식과려기내부수류결구화특성，위진일보결구우화제공의거，해문채용Fluent(6.3)연건대기진행료전류장수치모의。재분석과려기결구급자청세원리기출상，건립료과려기내부류장적수학모형화자청세계통적동망격모형，급출료과려과정화자청세과정계산구역화망격、이급진출구변계조건，대비분석료자청세류량여진출구압력강관계모의결과화시험결과。분석표명：모의압강여실측압강부합교호，가이보증후속모의결과적가고성；재차기출상，대과려과정내부류장진행료모의，득도료수류류속、문동능화압력적분포규률，분석료과려기결구설계불족。운용동망격기술，대과려기자청세과정진행료수치모의，통과류속、문동능화압력분포등류장분석，지출료자청세계통적불족，연구결과가위과려기결구우화설계제공삼고。
A self-cleaning screen filter has broad application on the domestic and foreign markets. The variation law of head loss, and the relationship between filtering time and self-cleaning time have been analyzed through different experiments. However, the flow distribution of filter inside cannot be obtained by traditional experiment methods. To fully understand the internal flow structure and characteristics of a self-cleaning screen filter and find the inadequacies of flow field distribution, the whole flow was simulated through Fluent (6.3). Based on the analysis of filter structure and self-cleaning principle, the mathematical model of inside flow field and the dynamic grid model of a self-cleaning system were established respectively, the computing area and the grid of filtering and self-cleaning processes, as well as boundary condition of inlet and outlet were proposed. In order to ensure the reliability of the simulation results, the relationship between the flow rate and pressure of a self-cleaning system were compared in this study, and the results show that the simulated pressure agreed with the measured values. The internal flow field of the filtering process was simulated, and the distribution law of flow velocity, turbulent energy, and average pressure were studied. The flow velocity decreases along the radial direction of the filter body, and it decreases rapidly from the inlet value of 2.6~3.0 m/s to the outlet value of 1.4~1.8m/s. The maximum average pressure was located at the inlet of flow, and the average pressure of the first filtering chamber was significantly higher than the value of the second filtering chamber, which the average pressure reduces relatively 25% and 80% after the flow passes the first and second filtering chambers. As the distributions of flow and turbulent energy are extremely uneven, the clogging of the entire screen is uneven. The design of inlet and outlet should be changed in order to avoid the uneven clogging of the entire screen, for example, several small-diameter screens replace a big diameter-screen. Moreover, through the technology of dynamic mesh, the process of self-cleaning was also simulated, and the flow fields of flow velocity, turbulent energy and average pressure were analyzed. The inlet of sunction will have a huge attractive power, which can ensure that the sediment of the screen surface be cleaned. But the velocity, average pressure, and turbulent energy of sunction vary greatly at different heights of sunction. The maximum and minimum values of velocity are located respectively at upper and lower sunction, and the maximum velocity difference is about 8.5m/s, which results in the lower screen being cleaned unthoroughly and the upper screen being damaged easily. The pressure gradient near the sunction is large, and the maximum pressure difference between outside and inside the sunction is about 1.1MPa. The maximum and minimum values of average pressure are located respectively at middle and upper sunction, which results in different cleaning efficiency at different heights of sunction. The maximum average value of turbulent energy is located at lower sunction, and a local high turbulent energy area also appeared at upper sunction. The simulated results of a self-cleaning system indicate that the distribution of sunction tubes can not be uniform along the axial direction, and the position of suction tubes can be adjusted and the number can be increased, which can increase the sunction power of lower sunction tubes and improve the cleaning efficiency of sediment.