Study On Wear Properties Of Materials' Cavitations Erosion In Fluid With Sand

Fluid with sand did severe harm to the hydraulic turbine transition parts and the hydraulic architecture. How to evaluate the wear properties of materials and improve them are the key problems that influence the further development of national hydropower.Based on the analysis of experimental methods of cavitations and impact erosion in China and foreign countries, this thesis brought forward some useful measures to improve the test machine or methods. The combined action of cavitations and impact erosion on representative materials of polymer and metal is studied considering the particularity of the national hydropower engineering. Based on the experimental result, a technique was designed to apply UHMWPE to the hydraulic architecture that holding 280 meter fall flood discharge holes. The experiment proved that UHMWPE enhanced the capability of hydraulic architecture to resist cavitations erosion in fluid with sand.Main innovations and results are described as follow:(1) The wear properties of the sample turntable materials used in MCF-30 impact erosion test machine have been improved. The cavitations erosion effect is displayed through designing sample with gibbous edge which working in local inflows.(2) An equipment of impact erosion under water is designed to be used for the GPS-S high pressure water jet impact erosion test machine. This equipment can produce the test effect of cavitations erosion and impact erosion.(3) The erosion mechanism of two stainless steels is investigated under the combined action of cavitations erosion and impact erosion. The wear process is discussed about the materials resisting the combined action of high speed fluid with sand.(4) The wear properties of three polymers and two stainless steels are studied. It finds out that UHMWPE is best to be applied under the conditions of high speed fluid with sand.(5) A protection structure of UHMWPE is designed to reduce cavitations erosion and impact erosion of the hydraulic architecture. It has achieved better effect in the local experiment. The experimental result is active and inspiring.