The Internal Flow Field Analysis And Noise Reduction Research Of The Backward Centrifugal Fan

Air conditioning is one of the essential equipment in people’s daily life.With the development of science and technology,the performance of various aspects of air conditioning is also continuously improving and improving.This paper focuses on the shortcomings of existing centrifugal fans,focusing on optimizing their efficiency and reducing noise.A backward-type centrifugal fan with high efficiency,low noise,and low loss was designed,and the rationality and superiority of the fan were verified by a combination of numerical simulation and experiment.The early method for studying the internal flow of impeller machinery is experimental method.The current modern optimization design method is based on three-dimensional theory and verified by experiments.The use of three-dimensional theoretical models for multi-state simulations saves costs and improves optimization efficiency.Firstly,the original fan model was established based on the existing flow characteristics in the centrifugal fan and impeller flow channels.Based on this,a centrifugal fan model with different parameters such as the inner diameter of the blade,the exit angle of the forward blade,the angle of the top bevel,the inlet angle of the blade,the size of the convex hull,the blade type and the welding slot of the blade is established.This provides the basis for subsequent internal flow field analysis and noise analysis.Secondly,Reynolds time-average equations are used in conjunction with turbulence models.With the help of STAR-CCM+ software,the internal flow field of different fan models is analyzed.Through the pressure cloud map,the actual performance of the fan can be predicted.The calculation results can provide reference for fan design and improvement,and compare with the original fan’s numerical simulation results to obtain various parameters.The influence of the air volume,pressure difference,and torque of the fan is measured by using the efficiency of the centrifugal fan as the evaluation index.The primary and secondary relationships of the influencing factors are determined using the extreme values,and the optimal combination of the fan structural parameters is obtained.Finally,using the centrifugal fan with the best combination of parameters as a model,a noise model algorithm was used to develop a three-dimensional unsteady numerical simulation to obtain a sound power cloud diagram on the fan surface,and the numerical simulation results were compared with the performance test results.It verifies the reliability of numerical methods.