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螺纹管内污垢热阻的对比实验研究 总被引:1,自引:0,他引:1
本文对一冷却塔中的7根螺纹管进行了长时间污垢实验研究.螺纹管几何参数范围:螺纹数18~45,螺纹角25°~45°,螺纹高0.33~0.55 mm.污垢是颗粒污垢和析晶污垢的混合物.本文基于普朗特类比,引入修正因子β(β=(A_w/A_(wp))/(A_c/A_(cp)),A_w为润湿面积,A_c为截面积,下标p表示光管),对半经验污垢预测模型进行修正,证明了螺纹管内参数对污垢热阻的形成影响很大,并建立了不同结构参数的螺纹管的统一结垢模型,对工程实际有一定指导意义. 相似文献
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This article presents an approach to the modeling of CaCO3 fouling and cleaning in a microscale cross-flow heat exchanger. The fouling progress was detected by thermal, fluid dynamical, and optical measures. In general, the observed fouling phenomena at microscale were comparable to those at macroscale. The detected thermal fouling resistance was between 10? 6 and 10? 3 m? 2 K? 1. As expected, crystallization fouling strongly depends on the surface temperature. In addition, the surface coverage can be a useful measure for both processes—fouling and cleaning. An extended approach to derive a reasonable fouling allowance was formulated through a fractional fouling resistance. 相似文献
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