含湿混合气体纵掠镀(涂)层管外壁的传热特性  

Heat-transfer Performance of Plated/Coated Pipes with Steam-Air Mixture Longitudinally Flowing over the Surfaces

作　　者：李诗[1] 吴新[1] 都艺伟 刘道洁[1] 孙立[1] 李军辉[1] 

机构地区：[1]东南大学能源热转换及其过程测控教育部重点实验室,南京210096

出　　处：《发电设备》2018年第1期1-6,共6页Power Equipment

基　　金：国家重点研发计划资助项目(2016YFB0600602)

摘　　要：为考察不同镀(涂)层管在烟气余热回收过程中的强化传热性能,采用水蒸气和空气的混合气体(w(H_2O)=6%~16%),对其在竖直紫铜管、镍-磷(Ni-P)镀层管及聚四氟乙烯(PTFE)涂层管表面的对流凝结复合传热特性进行了实验研究。结果表明:传热系数随着水蒸气质量分数和气体流速的增加而增加,PTFE涂层具有最佳的传热效果;水蒸气在紫铜管表面发生膜状凝结,在PTFE涂层表面发生珠状凝结,而在Ni-P镀层表面的凝结形式则表现为珠膜共存。对实验数据进行了多元线性回归,得到了含湿混合气体纵掠3种管子的对流凝结复合传热的Nu实验关联式,其理论值与实验值的相对误差在±15%以内,具有较高的准确性。To research the heat-transfer performance of different plated/coated pipes during flue gas heat recovery, experimental studies were conducted on the vertical copper pipe, Ni-P-plated pipe and PTFE-coated pipe, with steam-air mixtures longitudinally flowing over their surfaces （w（H2O）=6%~16%）. Results show that the heat-transfer coefficient increases with rising mass fraction of steam and with rising flow rate of steam-air mixtures, and the PTFE-coated pipe has the best heat-transfer effect. Film-wise condensation occurs on copper pipe surface, while drop-wise condensation forms on PTFE-coated pipe surface, and for Ni-P-plated pipe surfaces, both the film-wise condensation and the drop-wise condensation can be observed simultaneously. Based on multiple linear regression analysis of the experimental data, experimental correlations about convection and condensation heat transfer of above three pipes are obtained respectively, and the relative errors between theoretical values and experimental data are within ±15%, indicating that the experimental correlations have high accuracy.

关 键 词：对流 凝结 镍-磷镀层 聚四氟乙烯涂层 传热强化 

分 类 号：TK11[动力工程及工程热物理—热能工程]