| Solid-liquid fuel hybrid propulsion is an important component of aerospace propulsion systems.Liquid engine fuels have low thermal entropy.In order to improve the endurance of rockets or missiles,there is an urgent need to increase the thermal entropy of the fuel.In view of this,combined with the characteristic of high thermal entropy of solid powder fuel,the concept of solid-liquid mixed combustion is proposed to further increase the thermal entropy of the engine fuel in order to increase the cruising range of the engine.In the National Natural Science Foundation of China,"Theoretical Research on the Optimization Design of Spiral Curved Precision Forming Tool Tooth Profile Based on the Processing Process"(Project Number: 51575069)and the lateral project "Research on Solid-liquid Blending and Conveying Equipment"(Project Number:XXXXXXXX)Funded,the thesis focuses on the design and experimental research of solid-liquid mixed transportation systems,including theoretical research,model design,simulation calculation,experimental debugging,etc.,in order to achieve variable flow,variable ratio,variable pressure transportation of solid-liquid fuel,and uniform mixing and transportation.The main contents of this thesis are as follows:(1)In order to realize the solid-liquid mixed transportation with solid particles,under the premise of ensuring the volume efficiency,the tooth shape design of the key structure twin-screw is studied.According to the plane envelope theory of gear engagement principle and considering the engagement clearance,the design and modification method of screw tooth profile of screw pump are carried out.The influence of deep trimming method,isometric line trimming method and isometric surface trimming method on the engagement clearance is mainly analyzed,which provides the basis for the optimization of screw tooth profile in the future.(2)Three-dimensional model and flow field simulation model are established for the modified screw profile,such as deep profile modification,isometric profile modification and isometric profile modification.The flow field performance under different profile modification modes is analyzed,including the relationship between pressure field,flow rate and volumetric efficiency with rotation speed and pressure change,etc.,and the results of quantitative and qualitative analysis on the transportation performance are integrated On the basis of this,the best modification method is determined.(3)On the basis of the optimization of screw tooth shape,the design method of solidliquid mixed transportation system is studied around the uniform and variable proportion of solid-liquid mixture.The influence of the structural parameters of the screw conveyor on the conveying performance is studied,focusing on the requirements of the uniformity of solid-liquid mixing.Based on the in-depth analysis of the mixing effect of different mixing impellers,the optimal mixing structure is determined,which provides the basis for the development and experimental verification of the solid-liquid mixing system prototype.(4)Aiming at the solid-liquid mixed transportation system,the experimental platform is built,the hydraulic test system is established,the experimental matrix is designed,the experiments of solid transportation,liquid transportation and solid-liquid mixing are carried out,and the tests of pressure and flow are carried out.Based on this research system,the evaluation method of solid-liquid mixture uniformity is put forward.The performance of the whole machine is stable and the effect of mixed transportation is good,which meets the requirements of variable flow,variable proportion and uniform mixing.The fuel pump designed in this paper can provide reference for the design of variable thrust rocket engine. |
