用均匀流场准确校验气体大流量

The Uniform Flow Field Used for Precise Calibration of Large Airflows

为解决大口径气体流量计量,国内外长期以来均采用速度面积法。用这种方法确定一个流量必须在测量截面上测20点的流速,不仅烦琐,而且准确度也仅有±2%左右。为此,本文作者在试验室条件下,提出了均匀流场——修正法。这种方法是在装置上建立一个均匀流场,从而仅需测1个点的流速,即可确定流量值,简化了测试程序。再通过大量的测试数据,得到了附面层与雷诺数之间的经验公式,以此对流量值进行修正,提高了测试准确度。经测试鉴定,装置流量不确定度可达±1%。

To calibrate great airflows, the velocity-area method has longbeen adopted both at home and abroad. It is not only complicated, but also lowin accuracy, which is about±2%. The author of this paper puts forward the uniform flow field method underlaboratory conditions. By means of an established uniform airflow field in theequipment, where the velocity at only one point is to be measured, the flowratecan be determined. Thus the measurement is greatly simplified. Based on theexperimental formula of the boundary layer and the Renold's number, throughlarge quantity of measurement, we can revise the flowrate and improve theprecision. when put to test, the equipment shows an uncertainty of flowrateof ±1%.