水轮机叶片数控加工工艺研究

水轮机叶片作为机组的关键零件,其制造的好坏关系到机组的效率与寿命。水轮机叶片的数控加工是一项非常复杂、非常精细的工序,对每个工序的工艺参数都有严格的要求。在此基础上,采用先进的数字控制方法,对水轮机叶片进行优化设计,使其具有较高的制造精度,进而提高其综合性能。本文介绍了水轮机叶片数控加工的前期工作,并对其进行了技术处理,具体内容有:毛坯质量和余量的控制,叶片的刮检,叶片的夹紧和对中,叶片的加工;对叶片进行修磨和抛光,实践表明,采用该技术可以有效地提高水轮机叶片的制造质量与效率。

Theoretical evaluation on nitrogen removal of step-feed anoxic/oxic activated sludge process

Evaluation on nitrogen removal of step-feed anoxic/oxic activated sludge process at the standpoint of reaction kinetics and process kinetics was conducted. Theoretical biological nitrogen removal efficiency was deduced based on the mass balance of nitrate in the last stage. The comparison of pre-denitrification process and step feed process in the aspects of nitrogen removal efficiency, volume of reactor and building investment was studied, and the results indicated that step-feed anoxic/oxic activated sludge process was superior to pre-denitrification process in these aspects.