Study On Sound Insulation Characteristic And Structure Optimization Of Portable Generator Sets Enclosure

Generator sets are widely used in many areas. In military, generator sets are thekey equipment of logistics. They are usually used as the essential mobile power whensoldiers finish the field operations in a war. However, the high-noise of generator setsalso brought some negative effects. For example, noise makes our equipment easy forsophisticated defensive systems to detect, track and attack. It also can weaken combateffectiveness of armies and endanger the health of persons. Based on these reasons,making the control of noise has become a serious problem now. In the aspect of noisecontrol of generator sets, the enclosure is a more effective method. In this paper, thestudy object was the3.3Kw small diesel generator set’s enclosure. Based on the studyof noise source identification of generator set and structural insulation performance,the improvements of transmission loss of generator sets cover would be researched.The main noise source locations and sound power spectrum would be identifiedand tested. Sound source identification and sound power would be calculated usingacoustic holography method. The results show that main noise sources position on fanand air intake. The results also indicate that the biggest noise bands are octaves whichcenter frequencies are1000Hz and2000Hz.Acoustic radiation and insulation properties of plate were researched and soundabsorption materials’ properties were analyzed. First, sound radiation characteristicsand acoustic insulation characteristics were studied using numerical analysis method,including the impact of each parameter was analyzed. Then, porous absorptionmaterials’ characteristics were analyzed using impedance analysis method. And thecorrectness of results was verified using simulation method. Results can provide thebasis for researching of sound insulation characteristics and improvements of soundinsulation cover.Optimization of enclosure was studied. The sound power level in the cover wascalculated after the analysis of sound absorption. In order to determine the betterscheme, the thickness of the plate, composite plate and stiffened-plate influence oninsulation characteristics and insulation effect of sound insulation cover were studiedusing numerical simulation method. The results show that the enclosure withcomposite stiffened-plates were better than for intake，fan and exhaust sides andsingle plates could also satisfied the need for control plate side and the upside. Sound source identification of generator set with sound cover was tested. From theexperimental results, it was decrease about10.1dB (A) of the total sound power thatenclosure was used in a generator set. The level of noise was largely controlled.