| The jet aeration equipment is widely used in various fields of production and life due to its high mass transfer efficiency and good stability.Its performance is mainly determined by the working conditions and structural parameters,and the working conditions are related to the environment.Therefore,how to optimize the structure to make it better has been a major concern of scholars.Existing literature generally analyzes the effect on the performance of the jet aeration through the single-factor variable method,and has not considered the interaction between factors.In addition,the nozzle,as the most critical structure of the jet aerator,can realize the conversion between pressure energy and kinetic energy.The important structure of the jet aerator such as the diameter of the throat are also designed according to the nozzle size shows its importance,but there is not much related research.In addition,there is very little research on aerators with multi-nozzle structure,and it has the advantages of increasing the aeration area.New parameters are introduced due to structural changes.It is necessary to study the impact of these parameters on their performance.Therefore,this article has carried out research from several aspects such as the interaction of the structural parameters of the jet aerator,the analysis and optimization of the nozzle structure,and the structural design and performance analysis of the multi-jet jet aerator.The main work and results achieved are as follows:1)The influence of working conditions and structural parameters on the performance of the jet aerator was analyzed,and the structural parameters were optimized.Firstly,the structure size of the jet aerator was designed.Then,the single factor variable method was used to analyze the influence of area ratio,throat distance,throat length-diameter ratio,throat contraction angle,and suction angle on its performance.The value range of the parameter is better.On this basis,this paper has designed an interactive orthogonal experiment,and the test results are analyzed.The research results show that the influence of various factors on the performance from large to small is: area ratio > area ratio × throat length-diameter ratio > throat pitch > area ratio × throat contraction angle > length-diameter ratio > nozzle contraction angle > Area ratio × throat distance > Inspiratory angle,when the area ratio is 4,the throat distance is 8.1mm,the length-diameter ratio of the throat is 5.29,the throat contraction angle is 15?,and the suction angle is 50?,the jet The aerator has the best performance and its efficiency is 29.6%.2)Have been done a research to the nozzle structure of the jet aerator.Through the analysis and comparison of the flow field characteristics of the four types of nozzles: cone,straight cone,streamline and straight,it is found that the straight cone nozzle structure has better performance and is more suitable for the jet aerator.The parameters such as the length of the nozzle contraction section and the length-to-diameter ratio of the nozzle were orthogonally optimized,and the primary and secondary order of each factor was analyzed.The results show that the high-speed flow core area of the straight jet nozzle is longer,and the jet velocity decay is slower.Its aggregation and stability are better than the other three nozzles.Various factors affect the performance of the jet aerator from large to The order is: shrinkage angle > nozzle length-diameter ratio > shrinkage length.When the contraction angle is 13 ?,the contraction length is 40 mm,and the nozzle aspect ratio is 1,the jet aerator has the best performance and the efficiency is 30.6%.3)The performance of the multi-jet jet aerator was studied.First,a multi-jet jet aerator model was designed,its working process was analyzed,and then the appropriate number of nozzles was determined by numerical simulation.Finally,the two structural parameters that had the greatest impact on the performance of the aerator were selected,plus the introduction of the new structure.The parameters were tested by single factor,and finally the optimal value of each factor was obtained.The results show that the optimal area ratio of the threenozzle structure is 4.41,the length-to-diameter ratio of the throat is 6,the diverging angle is 50 ?,and the outlet angle is 40 ?.The multi-nozzle jet aerator has the best suction performance.In summary,the relevant research on jet aerators in this paper has certain practical significance,and to a certain extent,it can guide the engineering application parameters,so as to achieve the dual benefits of economy and environmental protection. |
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