本文实验研究了去离子水在直径为 1.0～2.0 mm 的细小圆管中的流动阻力特性.通过比较相同直径、不同管长的压差,获得了摩擦因子及局部损失系数随 Re 数变化关系.本文实验条件下,对于不同直径的细小圆管,沿程压降及局部压降随流速变化趋势一致;随着管径减小,摩擦因子也减小,且在层流区和湍流区内均要比常规尺度条件下的小;对于不同直径的细小圆管,局部损失系数随 Re 数变化趋势基本一致,当 Re 数相同时,管径越小,对应的局部损失系数越大;对于直径为 1.0～2.0 mm 的细小圆管,临界雷诺数 Rec=2050～2300.
The resistance characteristics of deionized water in minitubes with three different diameters ranging from 1.0 mm to 2.0 mm are experimentally investigated. The relation of friction factor and minor loss coefficient with Reynolds number are obtained. The results show that the variations of pressure drop and local pressure drop with mean velocity of fluid in minitubes are consistent basically.The friction factor decreases with the decrease of diameter. And the values are smaller than that in convectional scale in laminar flow region and turbulence flow region. The variations of minor loss coefficient with Reynolds number in the minitubes are consistent basically. The minor loss coefficient increases with the decrease of diameter under the condition of same Reynolds number. The critical Reynolds number is 2050～2300 in the minitubes with the diameter ranging from 1.0 mm to 2.0 mm.
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