大高宽比微小宽度矩形通道内的水力特性实验研究

An Experimental Study on the Hydraulic Characteristics inside Rectangular Channel with Big Aspect Ratio and Small Width

对高宽比 c=3～ 1 5共 5个矩形通道的流动进行了水力实验 ,实验通道的当量直径 dh=1 .0～ 1 .2 mm,通道宽 b=0 .6～ 0 .8mm,流动雷诺数 Re=5 0～ 1 0 0 0 0。实验结果表明 ,大高宽比微小宽度矩形通道内的层流流动计算应考虑高宽比的影响 ,不宜采用当量圆管的公式。与普通圆管流动相比较 ,其层流 -紊流的过渡区变窄 ,不出现 f -Re图上阻力系数 f随 Re增大而增大的那一小段曲线 ,以及层流到紊流的最大临界雷诺数Rec 随高宽比 c而变 ,其最大值为 2 3

An experiment has been made on the Hydraulic Characteristics of flow inside 5 rectangular channels with an aspect (height\|width) ratio c (3～15). An equivalent diameter of the experiment section is 1.0~1.2 mm , its width b is 0.6~0.8 mm . Reynolds number Re varies in a range of 50~10 000 . The experiment results show that the influence of the aspect ratio is ought to be considered in the calculation of laminar flow for rectangular channel with a big height\|width ratio and small width, and that the formula of equivalent circular duct isn't applied. Compared with flow inside common circular duct, the transition range from laminar flow to turbulence becomes narrow, so that there is not the friction factor f increases with Re in f\|Re plot, Critical Reynolds numbers Re c vary with the aspect ratio c , its maximum value is 2 340.