【作者】 高洋；

【导师】 尹洪超；

【作者基本信息】 大连理工大学 ， 热能工程， 2008， 硕士

【摘要】 我国是能源消耗大国,正处于经济飞速发展时期,能源消耗量逐年增加,城市生活污水和工业废水的产量也急剧地上升。广泛采用焚烧处理的办法是一种经济、有效、环保的措施,然而回收焚烧产物的余热成了工程设计的一大难题。本文从某废液焚烧炉余热锅炉的工程实际出发,分析和研究了实际问题的关键所在—强化换热与解决结渣问题。结合所学的理论知识以及相关领域的研究方法和方向进行实际问题的简化,应用fluent软件进行数值模拟,先是将实际的三维问题分成平面的和竖直两个方面来进行数值模拟,再从强化换热的方式和方法上出发,对比了直管和螺旋管的换热和流体动力特性,提出了进行管间距优化的模型。另外,从换热量、压力降方面比较详细地分析了挡板对换热量管换热和阻力特性,由实际的确定速度问题引发了进行综合考虑换热和阻力特性的速度确定方法—综合收益准则,提出可供工程参考的准则速度(极限速度和最优速度),并就此进行了深入的展开讨论。最后进行了结渣过程的数值模拟的尝试,通过目前对结渣现象认识的分析,得知只有将冷凝过程模拟的比较完善后,才能进行结渣过程的更真实的模拟。从水蒸气的冷凝过程的模拟入手,进行了无重力作用下窄通道内平行板间凝结换热数值模拟,对比分析了重力、相变对换热的影响。另外从非稳态的模拟给出了冷凝换热的两相流的流型的转变过程,并总结了模拟过程中存在的不足以及今后可发展的方向。对加强真实冷凝过程的认识具有很好的参考价值,为进一步的发展更完善的冷凝换热模型打下基础,也为模拟更复杂的具有物理化学反应的凝渣过程做好了铺垫。更多还原

【Abstract】 China is a big nation in terms of energy production and consumption. With rapid development of the economic, the total energy consumption has increased speedily year by year, as well as Urban sewage and industrial waste water production has also increased sharply. The incineration widely used is an economical, efficient and environmentally harmonious measure. However, waste heat recovery of the burning product has become a major engineering challenge.In this paper, a waste heat boiler of waste incinerator of a real project has been analyzing and studying, the actual crux of the matter is to enhance heat transfer and settle the slagging problems. With the combination of theory and related knowledge in the field of research methods and the direction, the practical problems are simplified to apply fluent software to numerical simulation. The complex problem is divided into two parts to carry out numerical simulation. In order to strengthen heat transfer, heat transfer and dynamic characteristics of the spiral tube and tube are comprised, and an optimization model to adjust the pitch of heat transfer pipe for enhancing heat transfer is set up. In addition, a more detailed analysis in the aspects of heat transferring, pressure drop on the tailgate-for-tube is made. The actual problem that the velocity is selected led to a comprehensive consideration of the characteristics of heat transfer and resistance to determine the velocity—Comprehensive income Criteria is made reference to the guidelines of the velocity, which would be widely referred in an actual projects (the limited velocity and the optimal velocity), which has also been widely discussed in depth.Finally, to attempt to numerically simulate deposition process, through the current understanding of the phenomenon of the deposition, what is realized that only that a fairly complete process of condensation was simulated; the simulation of the deposition process could be more realistic. So water vapor condensation between parallel plates in a horizontal miniature channels is tried to conduct by using Volume of Fluid (VOF) method as the start of the simulation of the deposition process. The comparison of condensation with gravity and without gravity has been made to analyze the effects of gravity on film thickness and heat transfer, and heat transfer was compared with no condensation. In addition, non-steady-state simulation of the condensation show out the two-phase flow pattern change with heat transfer, and shortcomings in the simulated process are summed up, as well as the developing direction in the field in future, which have a good reference value on strengthening understanding condensation and lay a foundation in the further development of condensation model. It also do a good job in paving the way for more complex simulation of the condensation slag process with physical and chemical reactions.更多还原