| Generator sets are commonly used as a kind of emergency power supply,but their work will be accompanied by a large noise,causing serious noise pollution,and the sound insulation and noise reduction materials used in the current set of sound insulation covers basically use traditional structures and materials,while the research and application of acoustic black hole(ABH)super structure is less.Therefore,based on the noise characteristics of generator sets and the principle of ABH,the design of a sound insulation hood embedded with ABH structure is of positive significance for the development of silent generator sets,the reduction of noise pollution in the surrounding environment and the promotion of the use of ABH structure.The main research content of this paper is to take the noise of generator sets as the research object,propose a sound insulation cover based on ABH theory,isolate the propagation path of the radiated noise of generator sets,and use a combination of experimental research and numerical simulation analysis to evaluate the noise reduction,ventilation and heat dissipation characteristics of ABH sound insulation cover.Firstly,based on the noise test standard of the generator set,the noise of each measurement point of the generator set under full load conditions was collected from a20 k W dedicated generator set and the noise spectrum characteristics were analysed.The test results show that the noise values of the generator set under this condition are 87.34 d B(A),86.67 d B(A),89.78 d B(A),86.72 d B(A),87.07 d B(A),86.69 d B(A),86.33 d B(A),83.48 d B(A),and its total A sound power level is 87.05 d B(A),exceeding the standard 70 d B(A),and the maximum target noise reduction was determined to be 17.05 d B(A);through the processing of the spectral analysis data of the unit noise,it was concluded that the unit radiated a large noise value in the frequency band of 80-1600 Hz.Secondly,different solutions based on acoustic black hole structure acoustic enclosure panels and louvres of louvres were designed,and the sound insulation characteristics of the panels and the sound insulation characteristics and ventilation and heat dissipation characteristics of the louvres of the different solutions were compared and analysed.The results of the comparative analysis show that: based on the analysis of the sound insulation characteristics and the noise characteristics of the generator set,it is concluded that the ABH parameters of m=2.0,b=0.1mm,four sides fixed support,embedded in one ABH panel and sandwich double layer single variable conditions have better noise reduction on the noise characteristics of the generator set;the louvers with single layer embedded with two-dimensional ABH,whose ABH parameters of m=2.1,b=0.5mm and two sides fixed support have better noise reduction on the noise characteristics of the generator set;the louvers with single layer embedded with two-dimensional ABH have better noise reduction on the noise characteristics of the generator set.The noise characteristics of the generator set have better noise reduction.Finally,based on the acoustic black hole structure,the noise characteristics of the generator set and the design criteria of the acoustic enclosure,the acoustic enclosure with embedded acoustic black hole structure was designed.Simulation calculations of the thermal performance and noise reduction simulations are carried out for the acoustic black hole hood embedded with ABH.In order to compare the effectiveness of acoustic processing ABH,this paper also makes a common acoustic hood of the same specification and carries out noise reduction tests on both types of hoods.The test results show that the insertion loss of the ABH-based noise barrier is 17.78 d B(A),which is 9.24 d B(A)higher than the insertion loss of the ordinary noise barrier of 8.56 d B(A). |
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