间冷式冰箱风道流场数值模拟及降噪研究

发布时间：2019-05-23 15:04

【摘要】：随着人们生活水平和家居环境舒适度的提高,家用冰箱的噪声性能已经越来越受到人们的关注,间冷式冰箱风道及噪声的优化工作对于节能减排和提高生活品质具有重要的现实作用。本文结合计算流体力学(CFD)和计算声学的知识,采用商用软件FLUENT,对间冷式风道流场的流动特性和气动噪声展开研究,旨在为冰箱风道优化设计提供参考,同时为缩短优化设计间冷式冰箱风道而开展的实验所需的时间提供支持。基于上述目标,本文主要开展了如下几个方面的工作:1)采用商用CFD软件FLUENT对冰箱风道进行流场和声场的模拟计算,建立了用于间冷式风道流场和噪声预测计算的数值模型。在模型建立过程中,分析了动静区域耦合计算以及其他一些数值设定的实现方法。2)结合冰箱风道噪声预测模型,详细分析了冰箱风道气动噪声的声源类别、噪声种类及其频谱特征。分析计算表明风道噪声的主要声源是风道出风口、导流板和离心风扇叶轮处产生的偶极子声源,以及在频率特性上体现了离散噪声和宽带噪声叠加的效果,这些结论可为冰箱风道的降噪提供思路和方法。3)对于离心风扇处于不同转速工况下的风道流场进行数值模拟,研究了其对应的气动噪声特点;通过对风道流场进行仿真模拟,分析了导流板和离心风扇叶片尾迹涡的产生原因,分析了风道内涡流及气动噪声的关系;分析了导流板位置和出风口收窄角度对风道流场及噪声的影响。4)通过数值和实验预测的方法验证了本文采用的计算方法和计算模型的适用性,为模型的普遍运用提供了依据。分析了计算模型的计算区域独立性和网格独立性,并通过实验结果与计算结果的对比,结果表明风道的噪声仿真计算值与实验测量值相差较小,频谱特征一致,误差处于可接受的范围。5)计算分析了不等距叶片和流道顺滑这两种降噪方法对于降低冰箱风道总噪声的影响状况,为降低冰箱风道噪声提供指导。
[Abstract]:With the improvement of people's living standards and home environment comfort, the noise performance of household refrigerators has been paid more and more attention. The optimization of air duct and noise in intercooled refrigerator plays an important practical role in saving energy and reducing emissions and improving the quality of life. In this paper, based on the knowledge of computational fluid dynamics (CFD) and computational acoustics, the flow characteristics and pneumatic noise of intercooled duct flow field are studied by using commercial software FLUENT, in order to provide reference for the optimal design of refrigerator air duct. At the same time, it provides support for shortening the experiment time needed to optimize the design of the air duct of the cold refrigerator. Based on the above objectives, the main work of this paper is as follows: 1) the commercial CFD software FLUENT is used to simulate the flow field and sound field of refrigerator air duct, and a numerical model for predicting the flow field and noise of intercooled air duct is established. In the process of establishing the model, the coupling calculation of dynamic and static region and some other numerical methods are analyzed. 2) combined with the prediction model of refrigerator duct noise, the sound source categories of pneumatic noise in refrigerator air duct are analyzed in detail. Noise types and their spectral characteristics. The analysis and calculation show that the main sound source of the duct noise is the dipole sound source produced at the outlet tuyere, the guide plate and the centrifugal fan impeller, and the effect of superposition of discrete noise and broadband noise is reflected in the frequency characteristics. These conclusions can provide ideas and methods for noise reduction of refrigerator air duct. 3) the flow field of centrifugal fan under different rotating speed is simulated, and its corresponding pneumatic noise characteristics are studied. Through the simulation of the flow field in the air duct, the causes of the wake vortex of the guide plate and the centrifugal fan blade are analyzed, and the relationship between the vortex and the pneumatic noise in the duct is analyzed. The influence of the position of the guide plate and the narrowing angle of the outlet on the flow field and noise of the duct is analyzed. 4) the applicability of the calculation method and the calculation model used in this paper is verified by numerical and experimental prediction methods. It provides a basis for the universal application of the model. The computational region independence and grid independence of the calculation model are analyzed, and the experimental results are compared with the calculated results. The results show that the noise simulation results of the air duct are less different from the experimental values, and the spectrum characteristics are consistent. The error is in an acceptable range. 5) the influence of two noise reduction methods, unequal distance blade and smooth flow channel, on reducing the total noise of refrigerator air duct is calculated and analyzed, which provides guidance for reducing the noise of refrigerator air duct.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM925.21

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