Abstract

Plate heat exchanger (PHE) has been widely used in energy transport fields for its high efficiency and compact structure. However, fouling is an intractable issue which reduces heat transfer efficiency and increases pressure drop. In this study, an experimental investigation on composite fouling characteristics of Ni-P-PTFE nanocomposite coating in corrugated PHE was conducted to evaluate the anti-fouling performance of this modified surface. The nanocomposite coating was prepared based on the stainless steel 304 plates through the electroless composite plating method. Clean tests and accelerated composite fouling tests were carried out, and the heat transfer and pressure drop performance of both the uncoated and coated plates was analyzed. Moreover, micro-structure of the surfaces and fouling deposits was mapped by scanning electron microscope. Compared to uncoated plates, the Ni-P-PTFE coated plates showed lower pressure drop by up to 15.8% and lower heat transfer performance by up to 17.6% at clean state. The smooth coating decreased the friction loss of the flow, while slightly increased the heat conduction resistance. The Ni-P-PTFE coated plates showed a significant anti-fouling performance, which decreased the fouling’s weight by 20.4% and the asymptotic fouling resistance by 28.2%, meanwhile reduced the pressure drop increment by 44.8%.

摘要

板式换热器（PHE）以其高效、紧凑的结构被广泛应用于能源输送领域。然而，结垢是一个棘手的问题，它会降低传热效率并增加压降。在本研究中，对波纹 PHE 中 Ni-P-PTFE 纳米复合涂层的复合污染特性进行了实验研究，以评估该改性表面的防污性能。纳米复合涂层是在不锈钢304板的基础上通过化学复合镀的方法制备的。进行了清洁试验和加速复合污垢试验，并分析了未涂层和涂层板的传热和压降性能。此外，通过扫描电子显微镜绘制了表面和污垢沉积物的微观结构。与未涂层板相比，Ni-P-PTFE 涂层板在清洁状态下的压降降低了 15.8%，传热性能降低了 17.6%。光滑的涂层降低了流动的摩擦损失，同时略微增加了热传导阻力。Ni-P-PTFE涂层板表现出显着的防污性能，使污损重量降低20.4%，渐近抗污能力降低28.2%，同时压降增量降低44.8%。