风机过滤单元送风均匀性理论分析及实验研究

Theoretical Analysis and Experimental Research on Air Supply Uniformity of Fan Filter Unit

分析了造成风机过滤单元风速不均匀的几个结构因素,对常见的风速不均匀度的计算方法进行了对比,探讨了其各自的适用范围,认为采用RSD(相对标准偏差)来评估不均匀性在现阶段是合适的。同时对影响风机过滤单元风速不均匀性的因素进行了理论分析,提出了将风速波动分为低频、中频和高频三种类型,指出滤纸打折形成的中频波动是起主导作用的因素,采样测试时需要基于该频率进行采样才能得到较为稳定的结果。综合考虑测试准确性和测试时间成本,建议10×10的测点数量较为合适。基于以上的测点布置和计算方式,通过实验的方式对一些常见参数对风速不均匀的影响进行了测试研究,发现距出风面的距离对结果有显著影响。

Analyzed several structural reasons for airflow velocity uniformity in the fan filter unit,compared common calculation methods for airflow velocity uniformity,and explored their respective applicability.It is believed that using RSD(relative standard deviation)to evaluate uniformity is appropriate at this stage.At the same time,the factors that affect the airflow velocity uniformity of the fan filter unit are analyzed theoretically.It was proposed to dividevelocityfluctuations into three types:low-frequency,medium-frequency,and high-frequency.And it is pointed out that the medium-frequency fluctuation formed by the pleating of the filter paper is the dominant factor,and the sampling test needs to be sampled based on this frequency to obtain a relatively stable result.Considering the test accuracy and test time cost comprehensively,it is suggested that the number of measuring points of 10×10 is more appropriate.Finally,the influence of some common parameters on the airflow velocity uniformity is tested and studied through experiments,and it is found that the distance from the outlet surfacehave a significant impact on the results.