Design And Analysis On Heat Transfer Characteristics Of Yankee Dryer

Currently, resource shortage and environmental pollution are restricting the development of China’s paper industry. Besides, papermaking equipment in China are antiquated, and large essential equipment mainly rely on the import. Therefore, reducing the energy consumption of paper industry, improving capacity for independent innovation, promoting the level of papermaking equipment are urgently required. The key of energy saving in papermaking equipment is drying section. As the critical part of drying section, cylinder dryer has been the research hotspots. A lot of work have been made to reduce energy consumption and improve the efficiency by researchers both at home and abroad. The energy-saving and efficient multiport cylinder dryer has attracted lots of attention in recent years. Yankee dryer is the core part of tissue paper machine which is mainly relied on import. The research subject of this paper is Yankee dryer, the research results of multiport cylinder dryer are applied to the structure design and optimization of the Yankee dryer, and design a novel Yankee dryer with high heat-transfer and high drying efficiency, in order to achieve the purpose of energy saving, and change the situation that large Yankee dryer in China mainly rely on import.The main work of this dissertation are as follows:(1) The research status of the multiport cylinder dryer and Yankee dryer were reviewed, and made a special effort to analyze the structure of Yankee dryers manufactured by ANDRITZ and TOSCOTEC, providing theoretical basis to the structure design and optimization of the Yankee dryer.(2) The novel Yankee dryer was proposed according to design concept of multiport cylinder dryer, which consists of inner shell, outer shell, head of dryer, metal tube reinforcement and vapor-condensate water circulatory system, etc. The outer shell with grooves and the inner shell forming many annular channels, forced convection heat transfer occurs while the vapor is following along the channels, and heat passes through the shell and dries the paper sheet. According to the dryer and pressure vessel design standard, the main components of novel Yankee dryer were designed and checked.(3) Every part of the novel Yankee dryer was modeled and assembled. The finite element statics analysis of the whole dryer depends on the finite element analysis software Workbench, and the results indicated that the design of the dryer can meet demands in practical use.(4) The model of annular channel in the novel Yankee dryer was established. By using CFD software Fluent, the flow process and condensing heat transfer process of vapor in the channel were simulated. The temperature distribution of the model as well as the average condensing heat transfer coefficient of the model were obtained. By further calculation, total heat transfer coefficient of upper surface of was obtained. The results indicated that the novel Yankee dryer have a higher heat transfer efficiency than the traditional Yankee dryer.Through the structure design, finite element analysis and heat transfer characteristics numerical simulation, the novel Yankee dryer with high heat-transfer and high drying efficiency was finally designed out. The results of finite element analysis show that the structure design is reasonable, the results of heat-transfer characteristics numerical simulation indicate that the heat transfer performance of novel Yankee dryer is superior to the ordinary Yankee dryer.