Study On Experiment And Simulation Of Aerodynamic Noise Of Wind-hood Of Refrigerator

The wind-hood is the main component of the air-cooled refrigerator air-cooling system,which plays an important role in the exchange of hot and cold air inside the air-cooled refrigerator and the temperature regulation between the compartments.Therefore,it is only to consider the cooling efficiency and the defrosting effect when designing wind-hood,but to ignore the low noise design of its structure.There are some noise of the windshield,such as the aerodynamic noise caused by the rotation of the centrifugal fan,the aerodynamic noise caused by the flow of fluid in the air duct cavity and the noise caused by the vibration of the wind-hood shell structure.In conclusion,the study of windshield aerodynamic noise has a great significance to the study of the overall wind-hood noise.With the development of technology and theory recently,the study of cavity aerodynamic noise has become a hot spot in aerodynamics.Most of the current researches are mainly focused on the noise of simple cavity structures under subsonic or supersonic airflow.However,the aerodynamic of complex cavitation structural with low-speed airflow(i.e.wind-hood of refrigerator)is less involved.In this thesis,the study of the aerodynamic noise of the refrigerator wind-hood was carried out by combining experimental test,structural dynamics analysis,computational fluid dynamics and computational aerodynamic simulation analysis.The main study contents include:The aerodynamic noise characteristic test bed was designed to separate the air-cooled refrigerator hood from the internal centrifugal fan,which can test the modal parameters of the hood shell and the aerodynamic characteristics of the cavity in the modal experiment and the vibration noise measurement experiment.The finite element model of the wind-hood cavity are established,which can implement computational fluid dynamics simulation and computational aeroacoustics simulation.Finally the flow field characteristics and frequency spectrum characteristics of the noise are obtained.Comparing with the experimental and simulation results,some key frequencies are present on both results.The causes of the difference between experimental and simulation results are also discussed.This thesis proposed a method to study the aerodynamic noise of the complex cavity.After analyzing the aerodynamic noise of the air bag,the composition and influencing factors of the aerodynamic noise inside the air chamber of the refrigerator are obtained.Which provides insightful information for noise control of the wind system.