混流式水轮机叶片数字化加工仿真技术研究

发布时间：2019-06-09 11:48

【摘要】：现如今,随着常规能源的日益匮乏和环境的不断恶化,清洁无污染的水能资源受到了世界各国的认可与青睐。同时水利发电技术成熟、成本低、可再生,有助于缓解各国用电紧张的问题,因此许多国家都不得不加快水利水电开发的步伐。可以想象,水利发电将逐步取代传统的发电方式成为发电行业的主流。水轮机是水力发电必不可少的原动机,转轮叶片又是水轮机的核心部件,因此,转轮叶片的制造质量和精度直接影响着水力发电机组安全准确,平稳高效的运行。水轮机转轮叶片是非常复杂的雕塑曲面体,传统的“砂型铸造——砂轮铲磨——立体样板检测”的制造工艺,并不能很好保证叶片的加工精度和质量。近年来,水轮机制造业一直探索采用五轴联动数控加工的方法制造大型叶片,但在采用该方法制造叶片时,仍然采用试加工的方式来检验和修正NC程序,致使叶片的制造周期长、效率低。而数字化加工仿真技术可以在计算机上模拟出零件切削的全过程,能较好的解决上述问题。本文以计算机辅助几何设计,数控加工仿真技术、软件的二次开发技术等理论作为依据,以某大型混流式水轮机叶片为研究对象,首先完成了叶片和相应加工机床的三维几何造型,叶片的五坐标数控加工刀位轨迹规划计算及其后置处理。在此基础上,构建了叶片的数字化加工仿真环境,并进行了叶片的数字化加工几何仿真。最后在对专业软件进行二次开发的基础上探索出一种将数控几何仿真和物理仿真相结合的数值模拟方法,实现了大型混流式水轮机叶片的五坐标数字化加工仿真和切削力模拟仿真,优化了切削参数,提高了叶片的加工质量。本论文研究成果不仅可用于描述仿真加工过程的空间几何运动,用于模拟叶片材料的切除过程,预测加工过程的表现、加工质量和加工效率。该成果可作为大型复杂叶片的多轴联动数控加工辅助编程的有效手段,代替实物试切削或试加工过程,大大地降低制造成本,保证加工过程中工艺系统的安全,对于推动水力发电设备制造业技术进步有重要意义。
[Abstract]:Nowadays, with the increasing shortage of conventional energy and the deterioration of the environment, clean and pollution-free water energy resources have been recognized and favored by all countries in the world. At the same time, the technology of hydropower generation is mature, the cost is low and renewable, which helps to alleviate the problem of electricity shortage in various countries, so many countries have to speed up the pace of water conservancy and hydropower development. It can be imagined that hydropower will gradually replace the traditional power generation method as the mainstream of the power generation industry. Hydraulic turbine is an indispensable prime mover for hydropower generation, and runner blade is the core component of hydraulic turbine. Therefore, the manufacturing quality and accuracy of turbine blade directly affect the safe, accurate, stable and efficient operation of hydropower unit. The turbine runner blade is a very complex sculptural curved body. The traditional manufacturing technology of "sand mold casting-grinding wheel shovel grinding-three-dimensional template detection" can not guarantee the machining accuracy and quality of the blade. In recent years, the hydraulic turbine manufacturing industry has been exploring the method of five-axis linkage NC machining to manufacture large blades, but when using this method to manufacture blades, it still adopts the way of trial machining to test and modify the NC program. As a result, the manufacturing cycle of the blade is long and the efficiency is low. The digital machining simulation technology can simulate the whole process of part cutting on the computer, and can solve the above problems. In this paper, based on the theories of computer aided geometric design, NC machining simulation technology and software secondary development technology, the blade of a large Francis turbine is taken as the research object. Firstly, the 3D geometric modeling of the blade and the corresponding machining machine tool, the five-axis NC machining tool path planning calculation and the post-processing of the blade are completed. On this basis, the digital machining simulation environment of the blade is constructed, and the digital machining geometry simulation of the blade is carried out. Finally, on the basis of the secondary development of professional software, a numerical simulation method combining numerical control geometric simulation and physical simulation is explored. The five-coordinate digital machining simulation and cutting force simulation of large Francis turbine blade are realized, the cutting parameters are optimized and the machining quality of the blade is improved. The research results of this paper can be used not only to describe the spatial geometric motion of the simulated machining process, but also to simulate the removal process of blade materials, and to predict the performance, machining quality and machining efficiency of the machining process. This result can be used as an effective means of multi-axis linkage NC machining auxiliary programming for large and complex blades, replacing the physical cutting or trial machining process, greatly reducing the manufacturing cost and ensuring the safety of the process system in the machining process. It is of great significance to promote the technological progress of hydropower equipment manufacturing industry.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TK730.6

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