| Jet pump is the fluid machinery by use of jet turbulent diffusion to transfer the energy and quality,the fluid machinery has been widely used in water conservancy, electricity,transportation,metallurgy,petroleum,chemical,environmental protection, marine development,nuclear power utilization,aviation and aerospace sectors.With the development of fluid mechanics and aerodynamics,promotion of the jet technology applications and research work made a big progress,jet pump is a very cost-effective general-purpose equipment and technology,and it shows great importance in economic life of mankind.In this paper,jet pump theory and design methods are systematic studied.Main work and research results are:1.Research on Multi-nozzle jet pump theory:derive out the jet pump's basic equation;and give a method to calculate the optimal parameters when the efficiency of jet pump device is the highest.In order to improve the efficiency of the jet pump,the measures can be taken includes:the use of pulse-jet or multi-shares Jet.Pulse jet,which have the functions of turbulent diffusing and piston pumps,use the multi-shares jet unit which makes the work fluid and the fluid being sucked fully mixed in a short period of the pipe,as a result of reducing the pipe's friction loss and improving entrance velocity distribution of the diffusion tube,then reducing the diffusion loss.2.Design Method:jet pump designs follow the optimal principle,that is in a given working conditions,get the highest possible efficiency.The performance of jet pump, performance curve,the basic equation of the jet pump and the description of jet pump similar to the law of the use of more convenient dimensionless parameters,the characteristics of jet pump is in accordance with the area ratio R,the flow ratio M,head ratio(also called pressure ratio) N to define.Obtain of the multi-nozzle jet pump's optimal parameters depend on single nozzle jet pump's characteristic curve and the characteristic equation when it under the same conditions.3.Study on jet pump's internal flow:study on the inside flow of the jet pump by three-dimensional numerical simulation,through the PIV measurement results of jet pump internal flow,then get the basic law of the internal flow.Have conducting an internal numerical simulation of flow field on single and multi-nozzle jet pump jet pump nozzles,it obtained a performance of multi-nozzle jet pump.The results show that:the simulation and experimental values agree well,and it provide a basis for further experiments.4.Study on jet pump experiment:by the design of orthogonal test,the different traffic flow at the import and export have been texted,as well as the import and export pressures,exploration based on a different number of nozzles,nozzle angles and throat from the mouth work on the multi-nozzle jet pump,then find out the optimal design of the program,and point out the further study direction that to achieve the optimal design. Orthogonal test pilot factors are as follows:the number of nozzles,nozzle angle,and nozzle from the hose.With orthogonal test method,9 times of test,and the study of the impact of the jet pump,we found that the number of nozzles,nozzle angle and throat from the mouth of the multi-nozzle have the increase impact;and when it have 4 nozzles,nozzle angle is 10°,and the hose nozzles is 50mm,the pump is best.5.Study on high-altitude performance of multi-nozzle jet pump centrifugal pump design:Researching on multi-nozzle jet pump,in order to enable the multi-nozzle jet pump applied to the production,tests centrifugal pump under the case of variety of multi-nozzle jet,the centrifugal pump installed multi-nozzle jet,have an increased import pressure.A multi-unit high-speed jet is used to enhance the energy of low-speed liquid being sucked,which make it rapidly mixed in the short pipes,thus substantially improved the cavitations performance of centrifugal pumps,and the installation of jet at the imports of centrifugal pumps can significantly improve the total head.
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