Effect of total phosphorous pollution on cavitation pressure characteristics of working water used in turbines

Many experiments have proven that with increasing silt and gas(out-of-phase media)content in water,the cavitation characteristics change and the cavitation pressure increases.Currently,many large reservoirs in China are polluted by total phosphorus(TP)and other chemical contaminants because of the use of phosphate fertilizer runoff from agriculture.However,research regarding how chemical pollutants(in the form of out-of-phase media)affect the cavitation pressure characteristics of water is sparse.In this paper,the Goupitan Hydropower Station,the largest hydropower reservoir on the Wujiang River,which is heavily polluted by TP,is taken as an example to evaluate the effects of chemical pollution on water cavitation pressure characteristics.In this study,the cavitation pressure characteristics of polluted and clean water are compared.The results show that the cavitation pressure of water polluted by chemicals is larger than that of clean water.In a hydraulic power generation system,cavitation and cavitation erosion are likely to occur earlier in runners when the fluid is polluted.These results are of great importance to further studies of cavitation theory and can directly influence the arrangement of turbines in practical engineering.     

古鲁金定理的推广

在求旋转体积的古鲁金定理的启发下，本文给出了沿一条曲线，用它的法平面去截一个立体，算出了截得图形的面积，再应用曲线积分来计算此立体的体积的方法。     

埃森归来满眼春

波罗地海的波涛伴着阿尔卑斯山的风随我一起归来；莱茵河的浪花与天上的阳光相映，两岸如画的风景与建筑勾画的优雅及浪漫画卷还在眼前浮现……收回远去的思绪，中国电焊机行业赴欧洲考察团即德国十六届埃森国际焊接博览会参观团带着期望与收获，载着德国的古典、法兰西的浪漫，携着中西焊接技术及文化交流成果圆满归来。     

Decisive influence of the ionization strength of cosmic rays on the cavitation characteristics of pure water

The experiment result in this article shows that the initial and critical cavitation pressure of pure water are both increasing along with the increase of height above sea level, and the ionization strength of cosmic rays in the lower aerosphere is the crucial factor which influences the cavitation pressure of pure water. The author concludes the relationship between the cavitaion pressure of pure water and the height above sea level. Moreover, air particles in water caused by the radiation of cosmic rays can exist in the water for a long time and will not escape.