平直斜翅管污垢特性研究

Study of the Characteristics of Foul on Smooth and Straight Obliquely-finned Tubes

通过进行平直斜翅管和光管在不同碳酸钙浓度和流速下的动态结垢实验,得出碳酸钙浓度、流体流速和管型对碳酸钙结垢过程的影响。实验结果表明:碳酸钙溶液流速的增加主要造成污垢表面剥蚀的加剧,从而使得结垢速率和结垢量减小,流速减小一半,则渐进污垢热阻值增加一倍多。相对于0.5和2.0 mmol/L而言,碳酸钙浓度在1.0 mmol/L时管道表面初始结垢速率和结垢量最大,后期由于溶液中浓度相似,污垢热阻值逐渐接近。平直斜翅管相对于光管来说,虽然其换热系数比光管要大,但其阻垢性能却不如光管,结垢速率和结垢量更多,其渐进污垢热阻值约为光管的1.6倍。

Through a dynamic fouling test of a smooth and straight obliquely-finned tube and bare tube at various calcium carbonate concentrations and flow speeds,obtained was the influence of the calcium carbonate concentration,fluid flow speed and tube type on the fouling process of calcium carbonate. The test results show that to increase the flow speed of the calcium carbonate solution will mainly result in an increase of the peeling-off force of the foul on the tube surface,thus decreasing the fouling speed and amount of foul produced,when the flow speed will reduces by a half,the thermal resistance value of the foul will increase by more than a fold. Relative to the calcium carbonate concentration of 0. 5 mmol / L and 2. 0 mmol / L,when such concentration is 1. 0 mmol / L,the initial fouling speed and the amount of foul produced on the tube surface will be maximal and afterwards,because of the similar concentration in the solution,the thermal resistance value will gradually approach to each other. Albeit the smooth and straight obliquely-finned tube has a bigger heat exchange coefficient than the bare tube,yet,its foul-resistant performance is inferior to the latter,thus resulting to a higher fouling speed and more amount of foul and its progressivefoul thermal resistance value is about 1. 6 times higher than that of a bare tube.