[arunraj]

Dear all,

I am trying to do acoustic analysis on an axial flow fan(sheet metal fan). Our aim is to get the same CFM(volume flow rate) at outlet with reduced noise by some passive means. So we have tried some techniques like fan blades with serrations(both sawtooth and slit) and fan blades with dimples. It is a steady state analysis. We have used FW-H(Focx-willams and Hawkings) acoustic model. Since it is a comparitive analysis, we thought of not worrying about the acoustic model. When we compared with the experimantal values FW-H gives closer noise value compare to experimental. So we understood FW-H model gives good result. I want to know how can be this analysis be carried out effectively. I hope you will be having some very good idea about this. All the journal says that the serrations/dimples causes noise reduction.But they are not talking anything about the CFM(volume flow rate) at outlet of the fan. I want to know what would be the better way for analysing this kind of problem where both same CFM and lower noise compare to the baseline case is needed. I want to learn the strategy for taking care of both CFM and noise into considerations for the comparitive analysis. Also what is the parameter (among turbulent kinetic energy, turbulence disspiation rate, turbulence eddy dissipation) which can be used for carrying out acoustic analysis more effectively.