Research On Flow Instability Of Constant Pressure Vortex Pump

Vortex pump is a kind of centrifugal pump,which is known for its internal rotating vortex motion.The characteristics of the vortex pump is good non-blocking performance,but its efficiency is low.Its impeller blade is straight,which structure is simple and easy to manufacture.However,there are many places which need to complete,in the research of flow state and design optimization.Therefore,it is the urgent need to research the flow pattern of vortex pump and it can also provide theoretical basis to design an efficient and stable vortex pump.The location of different inclined blade bending points of vortex pump is researched and its external characteristic is obtained.The vortex flow status inside the pump is optimized.The mantis shrimp is regarded as biological prototype and combined with the characteristics of ring volute of vortex pump,a bionic groove volute is established.Its noise reduction performance is also researched and its noise reduction mechanism is revealed.The cavitation characteristics between the modified model and the original model.The effect of modified model on cavitation is illustrated.The main works and results are as follow:1.According to the structure characteristics of the vortex pump impeller,the relationship between the locations of different R30-F30 inclined blade bending points,namely length of the second inclined section L,and performance parameters of vortex pump is researched.The simulation model which is suitable for vortex pump is established.The relationship between the locations of different inclined blade bending points and performance parameters of vortex pump is summarized.The effect among the performance,internal pressure,velocity and vortex is clarified.The causes why efficiency of vortex pump is low is explained.2.The pressure pulsation characteristics between impeller and volute were studied.Through bionic research of mantis shrimp,the bionic groove structure is extracted.One or One or more grooves are applied to the tongue for vortex pump.The bionic groove volute is established.By using moving mesh technology,vortex pump model of different groove number N are calculated under the standard condition,which ensure the modified model does not affect the external characteristics.Besides,the influence of groove on pressure pulsation is analyzed and the contour of static pressure,streamline and speed is clarified.In the meanwhile,noise reduction is achieved and the best groove number N is obtained.The goal of pressure fluctuation is achieved and the stability of vortex pump is also obtained.3.The influence of modification of impeller and volute on cavitation are studied.The cavitation calculation model vortex pump is established.The effect of the location of inclined blade bending points and bionic groove volute on cavitation are analyzed.And NPSH of vortex pump is also predicted.Based on the unsteady vortex pump cavitation model calculation,the cavitation condition inside the vortex pump is clarified.In addition,the law of the vortex pump cavitation is also summarized.The stability of vortex pump also has improved.