Optimization Of Low Frequency Noise Reduction Performance Of Cooling Tower Silencer

The noise reduction and pressure loss are important factors in evaluating the performance of the muffler,which is directly related to the power loss of the power plant and the noise reduction effect of the muffler.In order to increase the low-frequency noise reduction of the muffler and improve the fluid dynamics performance of the muffler,this paper used numerical simulation and experimental methods to study the resistance characteristics of the internal passage of the muffler and the influence of characteristic parameters of muffler perforated plate on acoustic performance of muffler.Firstly,study on acoustic performance of cooling tower muffler.The influence of the structural parameters of the perforated plate inside the muffler on the acoustic performance of the muffler was studied by COMSOL simulation.It was found that when the perforation rate was reduced,the cavity depth was increased,the thickness of the perforated plate was increased,and the aperture was increased,the noise reduction effect of the muffler in the low frequency region was enhanced.The multi-aperture perforated plate could improve the defect of the conventional single-aperture perforated plate with narrow bandwidth and only one resonance sound absorption peak,could increase the frequency bandwidth,and introduced multiple resonance sound absorption peaks.This part of the work provides theoretical support for increasing the low-frequency muffler of the muffler and designing the structural parameters of the perforated plate.Secondly,research on the resistance characteristics of the cooling tower muffler.Using FLUENT and experimental tests,the resistance characteristics of the internal passage structure of the muffler were obtained,especially the section of the expansion section.The angles of the expansion sections were changed to 0 degrees,8 degrees,10 degrees and 11.5 degrees respectively.The resistance characteristics of the muffler under various working conditions were obtained by numerical simulation.The velocity distribution and static pressure of the fluid along the axial direction were measured by experiments.Exploring the working conditions was a perforation plate with a perforation rate of 20%,a hole diameter of 3 mm and a plate thickness of 1 mm.The maximum angle at which the airflow does not flow apart in its divergent structure.This part of the work provides theoretical support for optimizing the internal channel structure of the muffler.Finally,optimization study of the internal passage of the cooling tower muffler.Through COMSOL and FLUENT,the noise reduction of the traditional cooling tower muffler and the fluid resistance of the internal passage structure of the muffler were analyzed respectively,and the reason for its poor performance was obtained.Combined with the research conclusions of this paper,by reducing the internal channel width of the straight-through section of the traditional muffler,the diverging structure was selected instead of the protruding structure,the structural parameters of the perforated plate were changed,the double-aperture perforated plate was selected,and the newly designed cavity structure and ordinary perforation diameter were used.Four new types of cooling tower muffler geometric models were designed by combining the perforated plates.Numerical simulation and experimental tests were used to analyze the resistance loss of each scheme to obtain a better solution,and verified its noise reduction effect at low frequencies.The results showed that the optimized model not only satisfies its noise reduction requirements at low frequencies but also has better aerodynamic performance.