电磁抗垢强化传热技术的热态实验研究

Experimental study of electromagnetic anti-fouling technology to enhanced heat transfer

在自行设计的电磁抗垢实验装置上,对热态工况下低频电磁抗垢(EAF)技术进行了实验考察。结果表明,在外加交变电磁场的情况下,总传热系数及污垢热阻发生了明显的变化,实验结束时污垢热阻下降了61%。不同的电磁场频率导致不同的抗垢效果,在本实验条件下,频率为700Hz时抗垢效果最佳。其他条件不变时,污垢热阻随着水质硬度的降低而减小,且不同流体硬度时污垢热阻的变化趋势均相同。对污垢晶体扫描电镜观察表明,经交变电磁场处理过的污垢晶体结构发生了明显的变化,由致密型易结垢的霰石变为松散型不易结垢的方解石,从而达到抗垢的目的,这一结论与冷态实验研究的结论一致。

The low frequency electromagnetic anti-fouling(EAF) technology was discussed on the basis of the experiment device devised by ourselves in the situation of heat state.The experiment shows that the changes of heat transfer coefficient and heat resistance of scale are very salient using EAF.The resistance reduced by 61 percent at the end of experiment.When the frequency changed,the effect of EAF was distinct, and the effect was the best when the frequency of magnetic field was 700 Hz.Under the same experimental condition but the liquid hardness changed,fouling resistance reduced along with the experimental liquid hardness decreasing. The observation of scale specimen through a scanning electron microscope indicated that the structure of fouling crystal changed. The hard and dense aragonite was changed into incompact calcite by EAF.The conclusion was consistent with the past experimental results.