The Research On Design Of AUV Counter-rotating Propeller And Flow Field Characteristics

AUV is a kind of underwater robot,and it is also a relatively new marine transportation tool in recent years.It plays an important role in various fields and has a broader development prospect.Regarding the choice of AUV thruster,applying the traditional single propeller to the AUV not only has low propulsion efficiency,but also prone to a series of problems such as vibration,cavitation,noise,etc.,which undoubtedly has a lot to the overall performance of the AUV.As a special type of propeller,the CRP,with its own unique structural arrangement,can well overcome the problems embodied by the traditional single propeller.Therefore,the research on the reasonable design and flow field characteristics of the CRP,it has a certain engineering significance and research value.The research work of this article is summarized as follows:This article first introduces the working principle of the counter-rotating propeller and its development and classification,and summarizes the current status of the research on CRP by scholars at home and abroad,discovers the deficiencies of previous work and leads to the work content and research significance of this article.Taking MAU4-40 propeller as the research object,a set of AU series propeller modeling platform is developed based on VB language,which simplifies the modeling process,derives three-dimensional coordinate points,and uses Solidworks modeling software to complete the final modeling.Based on the Reynolds time-average method,a set of numerical simulation methods were constructed,using SST turbulence model and polyhedral mesh,and the grid independence was verified.The open water performance of a single propeller was numerically simulated and compared with the experimental values.The results showed The numerical simulation results are in good agreement with the experimental values,verifying the feasibility of the numerical simulation method;then the matching parameters of the CRP with the MAU4-40 propeller as the research object are optimized(disk spacing and diameter ratio),and the open water efficiency A CRP scheme with excellent efficiency is designed for the index,and the comparison with the equivalent single propeller shows that the efficiency of the CRP designed in this paper is increased by about 14.49%.Comparing and analysis the flow field law of single propeller and CRP,including the interference of front and rear propellers,wake streamline and wake velocity field,and blade surface pressure distribution,the results show that the front propeller of the CRP has greater interference to the rear propeller.The CRP itself accelerates the wake velocity field obviously,has little suction effect on the wake of the rotating propeller,and has high energy utilization rate.It is better than a single propeller in performance;the blade shows a law of positive pressure on the blade surface and negative pressure on the back of the blade;Through the STAR-CCM+ coupling analysis module to analyze the fluid-structure coupling characteristics of the CRP under different materials,the results show that the deformation and stress of the front and rear propellers of the counter-rotating propeller under different materials are much lower than the safety factor and allowable stress.Scope,it is feasible to apply composite materials to the CRP designed in this paper.Finally,the calculation model grid was encrypted and the LES method was used to perform numerical simulation analysis on the wake vortex structure of single propeller and CRP.The results show that the tail vortex structure of CRP is more complex than that of single propeller.The dispersion is faster and the length of the vortex structure is shorter,which is beneficial to reduce noise and wakes.