贯流风机气动噪声数值计算与实验研究/Numerical and Experimental Analysis of Cross-flow Fan

2018-08-12 00:22:40

flow noise 噪声 fan Cross



摘 要
由于人们对家用空调器噪声指标要求越来越高,为了能在产品的设计阶段就对噪声进行控制,对空调室内机内部流场、噪声发生机理以及噪声源的位置等方面的研究就显得尤为重要。本文的主要研究工作包括以下几个方面:
1.本文通过对四种不同型号贯流风机在同一空调器中噪声状况进行反复实验测量,再结合各个风机结构上的差异,从其相对应的噪声频谱图中初步分析贯流风机的主要噪声类型。
2.采用FLUENT(CFD)软件对其中典型的贯流风机进行2D非定常数值模拟,再采用时域和频域方法对流场内蜗壳附近静压脉动的强度和频率进行分析,寻找贯流风机内部噪声源的位置及噪声类型。
3.利用FW-H方程成功预测出贯流风机的气动噪声,结果表明在定性上与实验数据吻合良好。随后,以各个可能的噪声源作为单独噪声源分别数值预测出其在观察点处的声压,直接比较该声压大小从而判断主要噪声源。
4.对贯流空调叶轮提出了相应的改进方法,并且通过数值计算对改进方案进行了噪声预测,找出了相对较优的设计方案。
通过本文的研究工作,指出了贯流风机主要噪声类型表现为离散噪声与宽频噪声并重的特性;主要噪声源在旋转叶轮部分和蜗舌区域。


ABSTRACT
As the high demand of air conditioner noise index, it’s significantly important to analyze the internal flow field, noise generation mechanism and the position of noise sources in order to control the noise at the design process of the product. The main research are as follows:

1. Based on theoretical analysis, noise measurement has been performed on four kinds of different cross-flow fan in the same air conditioner. Combined with the configuration differences of the four kinds of cross-flow fan, the conclusion that the main noise type of cross flow fan is discrete noise can be drawn according to specific noise spectra.

2. 2D unsteady numerical simulation is performed on different kinds of cross-flow fan using FLUENT. The time-domain and frequendy-domain analysis on fluctuating component of static pressure in the flow field are carried out. Based on the numerical results, the intensity and location of dominant aerodynamic noise source and the type of noise can be ascertained.

3. Aerodynamic noise of cross-flow fan is predicted successfully using FW-H functions, the results fit well with experimental data qualitatively. Then, the noise pressure has been predicted and compared numerically on every probable noise source on the assumption that it is the single noise source to find the main noise source.

4. Improvement method which had been put forward on cross-flow fan air conditioner is predicted numerically to get the optimal design scheme.

In conclusion, the noise of the cross-flow fan is dominated not only by the discrete characteristics but also by the broadband ones, the main noise source position is at impeller and tongue.