Experimental Research On The Performance And Cavitation Characteristics Of Mine High Speed Rescue Pump And Inducer

Mine rescue pump is a high power submersible pump which integrated pump and motor,it’s widely used in coal mine production and rescue.It can quickly discharge the water in the mine.Because the pump is heavy and large and the limitation of the mine shaft cage size and underground space,it will extend the rescue time if the pump is split and then reassembly underground.The mine high speed rescue pump of this thesis adopts frequency conversion technology to improve pump speed.Then the pump will be high head,small size and low weight.Besides,it can be installed quickly,which is meaningful to the emergency rescue and rapid recovery of production.At present,the research on mine high speed rescue pump is lacking at home and abroad.However,high-speed is used in the mine rescue pump also brought a series of new problems.High speed pump’s hydraulic performance,high energy consumption,high pressure structure,cavitation at inlet,motor cooling and axial thrust balance are urgent problems of mine high speed rescue pump.This project is derived from the National Key Technology Support Program Project of China "R&D on Quickly Rescuing Drainage Equipment During the Coal Mine Flooding Process(an Amphibious and Moving Drainage System)"(Granting No.2013BAK06B02).The purpose is to design and develop a high power,high head and small volume mine high speed rescue pump.The prototype is used as research objects.Theoretical calculation and analysis,numerical calculation and experiment were adopted as research methods.The study is mainly focused on the pump high speed hydraulic design and performance,the unit axial thrust balance,the inducer performance and cavitation,the internal flow of inducer.The main contents and innovative achievements of this thesis are as follows:1.This thesis systematically summarizes the research status and development trend of high power submersible pump,high speed pump and inducer,and analyzes the key technology of mine high speed rescue pump.It outlines the progress of pump internal flow analysis and calculation software application status.The research method of axial thrust balance of the unit and the research progress of flow field visualization are also discussed.2.Combined with the technology of existing submersible pump and high speed pump,this thesis developed a series of three specifications mine high speed rescue pump unit,including high power wet motors and three pump parts.Mine high speed rescue pump’s impeller,guide vane,other major components and the overall structure of the unit is designed.At present,this type of mine rescue pump with high power and high speed has not yet been found.3.This thesis discussed the numerical simulation method of external characteristics of mine high speed rescue pump.The clearance between the rotating parts and the cavity is considered in the numerical calculation,and full flow field modeling and model simplification are studied.The internal flow field of the pump is analyzed.The external characteristics of the mine high speed rescue pump were studied by experiments.Based on the numerical simulation results,the prediction accuracy and the external characteristics performance of mine high speed rescue pump are analyzed.4.This thesis calculated the axial thrust of mine high-speed rescue pump by the theoretical formula.Due to the inconsistent situation between the experimental results and the theoretical calculation of the axial thrust,the article uses numerical simulation to further investigate and analyze the axial thrust size.As the results of axial thrust shown,in the multistage impellers,the blade force axial thrust component has an important effect on the calculation and deviation of the axial thrust.The size of blade force axial thrust component is related to the stage of impeller and the area difference on both blade sides.5.This thesis discussed the existing design method of inducer,designed with four models of high flow rate and high speed inducer.The flow situation and external characteristics of each high flow rate and high speed inducer models at different speeds were analyzed by numerical simulation method.In the numerical calculation of cavitation flow in the high speed inducer,the cavitation phenomenon and the performance change rule of the high flow rate and high speed inducer were revealed.The independent experimental system of high flow and high speed inducer was built for the first time.It was used to systematically study the performance and cavitation of independent inducer,to analyze the situation and change of inducer head,efficiency,inlet cavitation at different flow rates and different speeds.In this thesis,the visualization of cavitation flow in the inducer was investigated for the first time.The method of high speed camera reveals the evolution of cavitation,the location of cavitation in the inducer,the degree of cavitation and the state of flow when the performance is affected.On the basis of experimental research,this thesis discussed the design theory problems and improvement direction of high flow rate and high speed inducer.