Comparison of modeled and measured aerodynamic noise for analysis of centrifugal blower noise

Najprej smo ugotovili, da je zniževanju širokopasovnega hrupa v sesalnih enotah smiselno namenjati pozornost, saj njegov doprinos k skupnemu hrupu ni zanemarljiv. Za tem smo se lotili iskanja parametra numeričnih simulacij, ki je povezan s širokopasovnim hrupom. Tega smo se lotili z izvedbo enostavnega eksperimenta z minimalnimi vplivnimi okoliškimi dejavniki. Preko valja smo pod različnimi pogoji natekali zrak. Eksperiment smo še numerično poustvarili, ob tem pa iskali izstopne spremenljivke simulacije, katerih trend in celo absolutna vrednost ustrezata trendom hrupa pri eksperimentu. V delu smo torej ugotovili, kateri izmed izhodnih parametrov v numeričnih simulacijah je povezan s širokopasovnim hrupom. Te parametre smo primerjali še s hrupom na realnem problemu generacije širokopasovnega hrupa na gonilnikih sesalnih enot. Za ta namen smo pomerili hrup sesalnih enot v gluhi sobi in amplitudno frekvenčnemu spektru odstranili izrazite vrhove. S pomočjo analize obeh eksperimentov, ki sta bila podkrepljena z numeričnimi simulacijami smo ugotovili, da sta izstopna parametra, ki sta najbolj povezana s hrupom: volumski integral turbulentne kinetične energije in logaritem volumskega integrala akustične zvočne moči.We first proved that it makes sense to pay attention in reducing broadband noise in vaccum units as its broadband noise contribution to total noise is not negligible. After that, we started looking for a parameter of numerical simulations, which is related to broadband noise. We tackled this by performing a simple experiment with minimal environmental influences. Air flowed through the cylinder under different conditions. After that, we numerically recreated the experiment, looking for simulation output variables whose trend and even absolute value correspond to the noise trends in the experiment. Therefore, we determined in the thesis which of the output parameters in numerical simulations is related to broadband noise. We also compared these parameters with the noise on the real problem of broadband noise generation on suction unit impellers. For this purpose, we measured the noise of the suction units in the deaf room and removed the prominent peaks of the amplitude frequency spectrum. Using the analysis of both experiments, which were supported by numerical simulations, we found thatthe following output parameters are most related to noise: the volume integral of turbulent kinetic energy and the logarithm of the volume integral of acoustic sound power