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基于三维椭圆形控制方程及熵理论,对电厂常用的G4-73型后向式离心风机进行数值模拟及熵产计算,并进行了实验验证。研究发现,叶轮体内熵产最大,且湍流耗散为风机熵产的主要来源,黏性耗散所引起的熵产几乎可以忽略。采用优化理论对叶轮参数进行优化,并分析比较优化前后的风机熵产及动力学特征。结果表明,优化后叶轮和蜗壳内熵产明显降低,流动得到改善;风机的全压升高、高效区拓宽,且流量越大,全压增长的幅值越大。最高效率点附近,风机全压和效率分别提高68 Pa和0.5个百分点。叶轮结构参数的优化对电厂的节能增效、解决风压不足和CO2减排等关键问题具有重要的现实意义。
Based on the three-dimensional elliptic control equation and entropy theory, numerical simulation and entropy production of G4-73 centrifugal fan, which is commonly used in power plant, are carried out and verified by experiments. The study found that the largest entropy production in the impeller body, and turbulent dissipation of the main source of entropy production fan, viscous dissipation caused entropy production can be almost neglected. The optimization theory was used to optimize the parameters of the impeller, and the fan entropy production and the dynamic characteristics before and after the optimization were analyzed. The results show that the entropy production in the impeller and the volute is significantly reduced and the flow is improved. The total pressure of the fan is increased and the high efficiency area is widened. The larger the flow rate, the greater the amplitude of total pressure increase. Near the highest efficiency point, the total pressure and efficiency of the fans were increased by 68 Pa and 0.5% respectively. The optimization of the structural parameters of the impeller has important practical significance for energy conservation and efficiency improvement of power plants, solving the problems of insufficient wind pressure and CO2 emission reduction.