Internal Flow Analysis And Performance Improvement Of Centrifugal Fan Fan-wall System

Fan-wall system is a new type of ventilator,which is composed of multiple voluteless centrifugal fans.The fan-wall equipment can adjust the performance of the system by controlling the number of the fan units.And the fan-wall equipment also has the advantages of low noise,energy saving and high efficiency,easy to maintain,easy to manufacture and so on.The fan-wall system conforms to the development requirements of China's ventilation equipment at the present stage.Therefore,it is necessary to explore the flow mechanism of the static elements within the fan-wall equipment which is of great significance to the design and optimization of the mechanical structures.In this thesis,the fan-wall used in the study is built by the YAM50-2232-S-L type centrifuge fan provided by the cooperative unit.The flow field characteristics of the fan-wall are analyzed by the method of three-dimensional numerical simulation.And the conclusion of the analysis is used to optimize the structure of the fan-wall.The main research contents of this thesis include the following four parts:In the first part,the numerical simulation of the interference effect of the fan-wall is studied.The mechanism and location of the interference effect are verified by setting up different experimental groups.The influence of the number of different fans on the switch of the fan-wall system is analyzed.And the arrangement mode of fan-wall fan is studied.It is found that the most important position in the interference effect is the inner clapboard of the fan-wall.Large vortices will be generated at the clapboard to affect the stability of the internal flow of the fan-wall.The research results have laid a foundation for the subsequent performance optimization.The second part analyses the common subunit closure and failure of the fan-wall in operation.It is found that when the fan-wall system needs to close the fan unit,it is necessary to close the inlet channel of the fan.The failure of the fan unit will greatly influence the overall flow performance inside the fan-wall and decrease the performance of the whole fan-wall.In the third part,the effect of the inflow on the performance of the fan-wall is studied.The results show that the stability of the inflow and internal flow is equally important to the performance of the fan-wall,both of which can greatly affect the working efficiency of the fan-wall.The full independent inlet conditions set in the study can widen the overall performance curve of the fan-wall system.Finally,according to the research foundation and the research conclusion of the first three parts,the numerical simulation study on the influence of the length of different clapboard on the performance of the fan-wall is carried out.By setting up clapboard with different lengths and without clapboard,the influence of clapboard on the performance of fan-wall is analyzed,and the influence of different length clapboard on the performance of fan-wall is analyzed.According to the analysis results,the optimal length clapboard is obtained,which achieves the goal of optimizing the performance of the fan-wall.