An Experimental Investigation of Jet Acoustic Characteristics Using Various Nozzle Geometries

Abstract

newline In this present research, it was planned to investigate the near field newlineacoustic characteristics and flow characteristics of the free jet with various newlinegeometries and Mach number. With respect to the geometry of the jet, it was newlineconcentrated both on circular and non-circular shapes (such as elliptical, newlinerectangle and chevron). Here, the influence of corners on acoustics and flow newlinecharacteristics in the near field of free jets was also studied. This kind of newlineresearch is very important to the understanding of noise generation, and it is newlineextremely important for aeronautical applications, for instance, the jet engine newlineexhaust. The research was done by analyzing the data obtained in experiments newlineusing Anechoic chamber, sound sensor and Arduino board. This work also newlinedescribed the experimental procedures for each step of analysis, as well as the newlinecharacteristics of jet noise facilities. The data from measurements with a sound newlinesensor was used to study the sound power level. These results were compared newlinewith literature and verified the accuracy of sound power level lower than 5%. newlineThe noise level data were obtained for Mach numbers 0.25, 0.40 and 0.7, from newlinethe nozzle exit to ten diameters in the direction of the jet. The acoustic study newlinewas carried out by analyzing the sound pressure level obtained at four positions newlinein the near field, with observer angles ranging from 0 to 90º. The experimental newlineresults of the acoustic characteristics behavior compared with the various newlinegeometry of nozzles with corner and without corner. Further, the experiment newlinewas simulated using CFD software. The Sound pressure level of elliptical jet newlinewas 9.6 % higher than circular jet, rectangular jet was 3% less than the circular, newlinechevron (A) jet with 6 corners was 6.3 % less the circular and chevron (B) jet newlinewith 8 corners was 9.2 % less the circular. The chevron nozzle showed higher newlinenoise reduction compared to other nozzles