针对污垢沉积引起换热管阻力变化的问题,建立了换热管内污水流动阻力变化的数学模型.本文提出管内污水流动的沿程阻力系数为洁净状态下换热管内污水的初始流速和时间的函数模型.基于此模型,通过理论推导获得了换热管内污水流动的沿程阻力系数表达式,分析了不同流动状态下沿程阻力系数的影响因素.通过试验获得了换热管污染后管内沿程阻力系数的半经验公式.结果表明:在考虑污垢底层影响时,管内污水流动的沿程阻力系数与洁净状态下管内污水初始流速和运行时间有关;该关系可用粘性底层的厚度和污垢厚度来表示.%In order to analyze the inner-tube sewage flow resistance is effected by the fouling,the mathematical model of the frictional resistance coefficient is established.In this paper,the initial velocity in the no-fouling condition and the running-time is seen as the influence factors to the flow resistance coefficient.According to the model,the formula of the sewage flow resistance coefficient in the heat exchange tube is obtained through the theoretical derivation and the experimental.The results show that the hypothesis is correct and the sewage flow resistance coefficient is expressed through the thickness of viscous sublayer and the thickness of fouling.
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