Analysis And Study Of Acoustic Characteristics And Vibration And Noise Reduction Of Air Cooled Refrigerator

Compared with the direct cooling refrigerator,air-cooled refrigerator reduces the complexity of the refrigeration device,greatly improving the cooling efficiency and temperature uniformity.However the number of noise sources and noise levels are to some extent improved due to the increase of air-cooled structure.As acoustic characteristics of the refrigerator compressor has been more mature and its noise is controlled well,the noise of air-cooled system has a great impact on refrigerator noise.Relevant statistics also reaveled that the noise and vibration problems of air-cooled refrigerators account for the major proportion of customer complaints and the harm of noise to human health.Based on the above background,this paper takes a domestic large-scale air-cooled refrigerator as the research object,adopts a variety of noise testing and calculation methods for further study of acoustic characteristics of the air-cooled refrigerator,to determine the main noise source of the refrigerator,and then to employ a highly efficient and feasible optimal design to complete the optimization of vibration and noise reduction for its main structure,so as to improve its overall performance.(1)Combined with the information provided by the manufacturer,the sound intensity test and structural sound test were employed to determine the air-cooled refrigerator composition of the noise contribution to the machine noise.Based on the analysis,the main noise source and its energy frequency distribution were identified.Taking the structural sound comed from the compressor vibration into account,vibration isolation test for compressor was conducted to analyze and estimate the vibration isolation performance of the compressor device.Based on the above test results of a comprehensive analysis,the basis and direction for further optimal design of the air-cooled refrigerator acoustic properties will be provided.(2)Aiming at the structural noise caused by the compressor,a four-point vibration isolation dynamic model of the compressor is established.The chaos particle swarm optimization algorithm based on the penalty function is used to optimize the vibration isolation parameters of the compressor system with taking the decoupling ratio of vibration isolation system as the optimization objectives,and taking the vibration dispacement and natural frequencies as constraints.Considering material processing technology and engineering practice experience,shape and size design of vibration isolator is completed,and ultimately obtain efficient and feasible design of vibration isolator.(3)Based on Latin hypercube sampling and neural network fitting,the proxy model between the response output and the design parameters of the air-cooled structure is established.The particle swarm optimization algorithm is employed to complete the acoustic optimization design with taking the air-cooled structure noise level as the optimization targets and the other flow responses as the constraint functions.Compared with original structure,the noise of the air-cooled structure from the optimized design is reduced by 4.98%and its overall flow rate is increased by 9.55%.What’s more,the ratios of flow rate among all outlets are controlled within 12%.(4)Based on the acoustic equation,the wind tunnel model for obtaining the performance parameters of the cooling fan is established.The influences of the blade airfoil,the number of blades,the blade thickness,the blade mounting angle and the fan hub ratio on aerodynamic performance and noise of the fan are stuied.Based on orthogonal experiment,the parameters of the fan blade are optimized and the optimal combination of the blade parameters is obtained.