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采用对比实验的方法对交叉缩放椭圆管与铜光管的传热和CaCO_3污垢特性进行了研究,并用数值方法模拟了交叉缩放椭圆管的内部流场和壁面剪切力。实验结果表明:交叉缩放椭圆管的换热和抗垢性能均优于在对应状态下的铜光管,这主要是由于交叉缩放椭圆管的内部流场和壁面剪切力的周期性变化所引起的。交叉缩放椭圆管在低流速时污垢热阻渐近值较大,当流速增大到一定程度后,再提高流速对污垢热阻渐近值的影响不明显。
The heat transfer and CaCO_3 fouling characteristics of the cross-scaled elliptical tube and the copper tube were investigated by the comparative experiment. The numerical simulation was used to simulate the internal flow field and the wall shear force of the elliptical tube. The experimental results show that the heat transfer and anti-fouling performance of the cross-scaled elliptical tube is better than that of the copper tube under the corresponding state, which is mainly caused by the periodic changes of the internal flow field and the wall shear force of the cross-scaled elliptical tube of. The asymptotic value of the fouling resistance of the elliptical tube with cross-scaling at low flow velocity is larger. When the flow velocity increases to a certain extent, the effect of increasing the flow velocity on the asymptotic value of the fouling resistance is insignificant.