石墨烯-PFA复合材料换热器与金属换热器的传热性能对比

氟塑料换热器以其耐腐蚀、耐磨损等优点而备受关注,但氟塑料热导率较低,换热能力差,限制了其广泛应用。石墨烯-PFA复合材料兼具石墨烯优异的导热性和可熔性聚四氟乙烯(PFA)良好的耐酸碱腐蚀性,是新一代的换热器材料。搭建了余热回收测试实验台,对石墨烯-PFA复合材料换热器和金属换热器的传热性能进行对比。研究了不同烟气流速、不同进口烟气温度以及不同石墨烯配比对复合材料传热性能的影响。结果表明:对于金属换热器和复合材料换热器,当烟气流速从2.0增加到4.0 m/s时,传热系数分别增加到原来的1.19和1.34倍;随着进口烟温的升高,两种材质的传热系数分别降低了15.6%和14.7%;随着石墨烯含量增加,复合材料的导热系数以及传热系数均增加。

Comparison of heat transfer performance between graphene-PFA composite material heat exchanger and metal heat exchanger

In recent years, fluoroplastic heat exchangers have attracted much attention due to their corrosion resistance and wear resistance, but the lower thermal conductivity of fluoroplastics contributes to a weak heat exchanging capacity, limiting the application of heat exchangers. The graphene-PFA composite material has both excellent thermal conductivity of graphene and good acid and alkali corrosion resistance of fusible polytetrafluoroethylene (PFA), and it will become the new material of heat exchanger. In this paper, a waste heat recovery test bench was built to compare the heat transfer performance of graphene-PFA composite material heat exchangers and metal heat exchangers. The effects of different flue gas flow rates, different inlet flue temperatures and different graphene ratios on the heat transfer performance of the composites were investigated. The results show that the composite material has better heat transfer effect than the metal heat exchanger; When the flue gas flow rate increases from 2m/s to 4m/s, the heat transfer coefficient increases to 1.19 and 1.34 times respectively. With the increase of the inlet temperature of exhausted gas, the heat transfer coefficients of the two materials decreased by 15.6% and 14.7%, respectively. Improving the graphene content in PFA, the thermal conductivity of the composite and the heat transfer coefficient increased.