报告题目：A New type of cavitation Triggered by boundary-layer turbulent Production 报告人：Prof Shengcai Li, School of Engineering, University of Warwick, UK
The Francis turbines (710 MW) of the Three Gorge Project are the world largest. They are developed by world leading manufactures (Alstom, GE and Voith-Siemens), reflecting cutting-edge technologies. However, all these turbines have developed an unusual pattern of damage neither identified nor reported before. This puzzled professionals around world. Li identified this new type of cavitation and now works to determine its mechanism which we know little currently.
The fact that this cavitation occurs on all prototype turbines but no cavitation was detected during model tests has raised a fundamental question to the turbine similarity laws. Fluid dynamic and metallurgical analysis suggests that this cavitation is triggered by the boundary-layer turbulent production; and the damaged (roughened) spot in turn trigger subsequent cavitation (damage) immediately down stream. This forms a sustainable dynamic process, resulting in long and equal-width stream-wise damage-strips with span-wise regularity reflecting the span-wise stochastic characteristics of turbulent production. Owing to the heat effect of cavitation, inter-granular corrosion takes place through sensitization process, leaving damage surface a corrosion appearance. Also, bluing presents at the damage tails owing to the nature of low-intensity damage. Extremely large turbines are much more susceptible to this type of cavitation (damage) owing to the scale-effect.
This phenomenon of highly multi-disciplinary nature presents a grand challenge to fundamental sciences as well as to development of modern turbines and other devices.
Professor Shengcai Li, School of Engineering, Warwick University
Professor Li is an internationally renowned academic specialised in turbo-machinery and its cavitation phenomenon. He is the Leader of the Cavitation Research Group in the Civil and Mechanical Division of Warwick’s School of Engineering. Under his leadership, Warwick has now become an internationally renowned centre for cavitation studies. He is also an Executive Member of the International Research Centre of Hydraulic Machinery (Beijing); and the Series Editor of the book series of hydraulic machinery and the Editor & Co-author of the first title ‘Cavitation of Hydraulic Machinery’. He has been listed in the Who’s Who of Science Engineering since 2003 and the Who’s Who in the World since 2008.
Prof Li started his career as a research engineer in later 1960’s at the Ministry of Water Resources and Electricity, China, where he developed the novel concept of double-row cascade runner for high performance hydraulic turbines and the first generation of semi-conductor dual-control governor BDT-100 for Kaplan turbines. He was among the first group of Chinese scientists selected in 1978 for working in abroad. Since later 70’s he guided his research into fundamental phenomena of cavitation, discovering a phenomenon named as Cavitation Resonance while working at the Cavitation & Multiphase Flow Lab, University of Michigan in USA. He also established a hydraulic turbine lab for cavitation research in China in 1980’s and recently a novel cavitation research lab at the Warwick University.
李胜才教授，英国华威大学工程365bet体育在线官网。他从事水轮机空蚀与机理研究40年，在空泡机理和抗空蚀水轮机的研究方面做出了开拓性的工作。他是水力机械全书的主编。由他主编的’Cavitation of Hydraulic Machinery’（水力机械空化）一书于2001年出版以来获得了国际同行的广泛认同, 多次被国际一级刊物的综述和评论文章引用并经常被指定为国际讲学班的参考书。由他主持的每三年一次的空化国际会议‘WIMRC CAVITATION FORUM’是透平机械空化的主要国际学术交流平台。