Research On Cavitation Damage Property In Centrifugal Pump With Non-Smooth Surface Blade

Cavitation damage is one of the main reasons causing the failure of the centrifugal pump.Cavitation damage is closely related to the unsteady evolution of bubbles and cavitation damage always accompanied by noise and vibration.It leads to a significant reduction in the efficiency of the pump which seriously affects the safety of the centrifugal pump.Therefore,it is urgent to study cavitation damage characteristics of centrifugal pump and explored the relationship between the unsteady evolution of the bubbles and the damage characteristics of cavitation.It is of great significance to clear the fluid flow state in the pump and the mechanism of cavitation damage generation.In this paper,through the extraction of the natural biological surface structure,a bionic non-smooth surface structure is established on the suction surface of the blade that is most likely to cavitation in a centrifugal pump.The non-smooth blade is used to explore the improvement of pressure pulsation,cavitation and cavitation damage in the pump.This help us understand the mechanism of improvement of non-smooth surfaces.The main research work of this paper is as follows:1.In accordance with the surface structure of mantis shrimp,the biological surface structure is extracted,abstracted and simplified,and a bionic non-smooth surface structure is arranged on the blade suction surface where centrifugal pumps are most likely to cavitation.Studying the influence of bionic non-smooth surface structure on the cavitation performance of centrifugal pump to find the best bionic non-smooth surface structure with anti-cavitation performance and to explain the reason why the cavitation causes a decrease in the head and efficiency of centrifugal pump.The results show that the generation of bubbles can easily block the flow passages in the impeller and cause the decline of head and efficiency.The circular non-smooth surface structure has the best anti-cavitation performance;2.This paper continues to explore the influence of circular non-smooth surfaces on the cavitation performance of centrifugal pumps.The change of gas content and pressure pulsation at monitoring points are analyzed and the best non-smooth surface structure is defined which achieves the purpose of cavitation while reducing pressure pulsation in pump.The results show that the circular non-smooth surface structure with d=1mm has the best anti-cavitation and improves the pressure pulsation effect;3.The anti-cavitation properties of the circular non-smooth surface structure with d=1mm are clear.On this basis,the influence of circular non-smooth surface with d=1mm on the cavitation damage characteristics is further studied.The relationship between cavitation evolution and cavitation damage is determined by analyzing the gas content and cavitation damage energy release value of the monitoring point under different cavitation allowance.By analyzing the relationship between impeller void fraction and cavitation damage intensity and damage area,the influence of circular non-smooth surface with d=1mm on cavitation damage of centrifugal pump is obtained and the mechanism of improving the cavitation damage of centrifugal pump by non-smooth surface is clarified.The results show that the circular non-smooth surface structure with d=1mm can improve the distribution of voids at the wall surface of the blade,effectively reduce the cavitation damage degree in the centrifugal pump,and reduce the cavitation damage area.4.The performance of non-smooth surface centrifugal pump was studied by test method.The cavitation performance of circular non-smooth surface centrifugal pump with d=1mm was tested.The results show that the experimental values are close to the numerical simulation values and the numerical simulation accurately reflects the cavitation performance of non-smooth surface centrifugal pumps.The circular non-smooth surface structure with d=1mm is better than the smooth surface cavitation performance.