丁胞型圆管CaSO_4的污垢特性

CaSO_4 fouling characteristics on dimple tube

建立了丁胞管物理模型,采用标准k-ε方程和SIMPLE算法,研究了丁胞管内CaSO_4流体的污垢特性,分析了结构与运行工况对丁胞管内CaSO_4污垢特性的影响。结果表明,丁胞的顺排叉排对于污垢热阻渐进值影响极小。高Reynolds数时,与光管的污垢热阻相比,丁胞的存在会减小污垢热阻值;而在低Reynolds数时,相对深度较小的丁胞反而会增大污垢热阻值。丁胞的相对深度与丁胞的相对密度对于污垢热阻值均有较大的影响,在丁胞深度为0.8时,丁胞管的抑垢效率为1.150。在丁胞的相对密度为5.30时,其抑垢效率为0.730。丁胞管抑垢率随着进口流速增长而增大,随着工质浓度增长而减小,随着壁面温度的增长而减小。

A physical model of dimple tube was established.The effects of structure and working conditions on CaSO4 fouling characteristics were simulated based on standard k-εequation and SIMPLE algorithm.The results show that dimple arrangement has little effect on the fouling resistance asymptotic value.For the high Reynolds number,the fouling resistance of dimple tube is always smaller than that of smooth tube.For the low Reynolds number,the fouling resistance of the dimple tube with a low height is slightly higher than that of the smooth tube.The height and density of dimple have a remarkable effect on the fouling resistance.The anti-fouling rate of the dimple tube is 1.150 and 0.730,when the dimple height is 0.8 and the dimple density is 5.30,respectively.Furthermore,the anti-fouling rate increases with the increase of the inlet flow rate,and decreases with the increase of the working fluid concentration and the wall temperature.