Experimental investigation of noise generated by multifunctional refrigerating units

摘要

At the development of multifunctional refrigerating units a principal unit was selected,which is located in the bottom part of the appliance.It is composed of three sub-units including compressor,dynamic condenser and electronic regulation.We present the optimization procedure of acoustic and aerodynamic properties of the unit.Acoustic properties were determined in the semi anechoic room on the basis of sound power level measurements,spatial sound intensity measurements and sound pressure level spectra measurements.Aerodynamic properties of the flow were measured by hot-wire anemometry.Mechanisms of noise generation were estimated and necessary design improvements were performed.Minimum noise emission of noise sources and high efficiency of the cooling system was achieved using variations of geometry of sub-units,inlet grille,position and selection of fans and type of installation. Procedure of optimization is presented with reduction of generated noise levels for each optimization step.The final required sound power level and cooling efficiency of the appliance were successfully achieved.