自转清洗式平带传热强化自然循环蒸发器的研究

Research on heat transfer enhancement of fouling removal and straight strip-inserts in natural circulation evaporator

为了解决传统蒸发器结垢需要频繁的停车清洗和强制循环泵高电耗两大难题,研究的新型蒸发器结构特点主要是加热室比较短、采用具有高效传热强化和较低流速下自转清洗功能的平带,沸腾室是大横截面的中心循环管,而且出口段截面为渐扩形。试验研究表明:这种平带的对流传热强化幅度可以达到92.3%,并且能够在传热管内流速大于0.35 m/s时开始自转;这种蒸发器能够为可靠自动清洗要求的自然循环设计流速0.70 m/s提供所需的推动力,并且对各种蒸发工艺条件具有良好的适应性。

To solve the problems of high electricity consumption of the force pumps and frequent cleaning operation caused by the serious crystallizion in traditional evaporators, a new design of the evaporator was developed. The structure was characterized by the short heating chamber and the straight strip-insert to enhancing heat transfer and remove fouling at low flowing velocity. The boiling chamber was a center circulating tube of large cross section and the section becomes greater gradually at the outlet. The experiments show that the convective heat transfer can be enhanced by 92.3% and the straight strip-insert begins to spin at low flowing velocity of 0.35 m/s. The evaporator of such structure can provide enough driving force of natural circulation of 0.7 m/s and realize automatic fouling removal. It has good adaptability for various evaporating process.