But when experiment lasts longer time, fouling resistance and heat transfer coefficient change in the same trend as the fore results at the beginning of the experiment.

• 当实验时间延长时，发现污垢热阻及换热系数在实验开始时的变化趋势与前面的实验结果基本相同，但到后来，二者的数值则分别均趋于稳定。