热管式空气预热器整体优化及CAD研究

【作者】 金永慧；

【导师】 梁延德；

【作者基本信息】 大连理工大学 ， 机械工程， 2003， 硕士

【摘要】 热管是一种新型的传热元件，由于是以内部工质相变和连续工质循环实现热量传递的，因此具有较高的传热效率。目前对热管的应用已有很大的进展，如在空间技术发展中以成功的实现传热和监控问题；在地面各方面应用中则更多。以热管为传热元件的热管换热器具有下列特点：传热效率高，压力损失小，工作可靠，结构紧凑，有利于控制露点腐蚀等，这些独特的优点是它在解决能源问题，如：利用热能、节约原料、降低成本等方面，特别是在工业余热利用中发挥了越来越多重要的作用。 由于热管换热器形式多样，结构复杂，因而如何选择其形式是工程应用中的一个重要环节。本课题就是要针对这一问题，对热管元件及热管换热器整体优化设计进行研究，以气---气热管换热器中典型代表---热管空气预热器为例，利用最优化理论，提出了对其进行整体优化设计的方法。文中详细阐述了如何分析实际的物理过程，如何确定优化对象的设计变量，建立了年净收益最大为目标的目标函数，确定了由实际过程及技术参数所构成的约束条件，从而建立了优化设计的最优化数学模型，并采用穷举法和复形调优法对热管换热器的热管直径d₀、热冷流体侧翅片间距S_fh、S_fc、翅片厚度δ_fh、δ_fc、管束横向管间距S_τ及冷热流体的迎风流速u₀₁、u₀₂（其中，热管基管直径、冷热侧翅片间距、翅片厚度、管束横向管间距这六个变量为离散型变量；冷热流体迎风流速为连续型变量）进行优化，就是通过对优化变量d₀、S_τ、S_fh、S_fc、δ_fh、δ_fc、u₀₁、u₀₂的调整，在满足给定的设计依据与条件下，使年净收益最大，即使目标函数值最大。 通过理论研究和相关问题研制，以及对具体事例进行计算和分析，并与常规设计计算结果进行比较，最后得出结论：本文所编制的计算程序可进行热管预热器的优化设计，能确定热管预热器的最优化结构参数及运行参数。在考虑热管预热器技术经济指标基础上，导出的年净收益方程，对于预热器优化选型有很好的指导作用。热管元件、预热器整体结构参数的优化组合既节省了初始化投资，又可降低运行成本，保证了设计质量，从而获得可靠的经济效益，为工程设计提供了设计思路。更多还原

【Abstract】 With high efficiency in heat transferring, heat-pipe is a new king of component ordevice. The heat transfer of heat pipe is carried out by phase change of the medium and continuous loop of the medium. The heat pipe technology on heat transfer and supervising in space science has been solved. The heat pipe is now used widely in industrial engineering. The heat pipe exchanger has the advantages of compact, controlling erode of acid dew point, high efficiency, low pressure drop loss and reliability, so they are used widely in heat energy utilization and waste heat recovery. It is also helpful to recover the waste heat, save the raw materials and reduce the production costs. Economic benefit from application is obvious.Heat pipe exchanger has many types, so it is important to know how choose suitable one in engineering application. This thesis focuses on the overall optimal design of pipe parts and head pipe exchanger. An example is also presented to stand for the typical heat pipe heat exchanger (that is, head-pipe air pre-heater). The specific details and methods are introduced in the integrated optimal design and the optimal selection for head pipe heat exchangers. The method how to analysis practical problems and determine design parameters and constraints are given to solve practical process and technical conditions. In order to optimize the heat pipe diameter, space of fin, pipeline space, thickness of fin and windward velocity of flow are selected as optimal parameters. Some of them such as head pipe diameter, space of fin in cold liquid side, pipeline spacing, thickness of fin in cold liquid side and thickness of fin in hot liquid side are dispersing variable. Windward velocity of flow is optimized. We use combinatorial method for dispersing variable and use plural adjusting optimum method for successive variable. The maximal net investment income is considered as object function and a mathematical model about the optimum design was established and optimal answer is obtained by adopting limit illustration method and plural adjusting optimum method.The computer program of the optimal selection for heat-pipe pre-heater is developed. According to comparison the optimization result with the conventional design result, it shows that program can optimize to determine the sizes of parts of heat-pipe p re-hate and give the most optimal parameter. The equation of the maximal net investment income can assist the optimal selection for pre-heater. So the method can save initial investment and cut operating cost obviously. The software can also optimize p re-hate with different medium and can be used as counsel of engineering design and provide design philosophy for engineering application.更多还原