【作者】 乔竞；

【导师】 江楠；

【作者基本信息】 华南理工大学 ， 安全技术及工程， 2010， 硕士

【摘要】 管壳式换热器是工业中应用非常广泛的一种换热设备,其结构坚固,承压能力高。随着换热器强化传热技术的深入发展以及石化装置的大型化、高参数化(高温、高压),壳程带外导流筒的管壳式换热器日趋增多。外导流筒换热器是一种在普通管壳式换热器壳体上进行了改动的新结构。它一般由“大圆柱壳──正环壳──锥壳──负环壳──小圆柱壳”五部分组合而成。这种结构能使流体更均匀地流入管间,增大壳程传热面积和提高换热器总的传热效率,减少动力消耗,并能防止流体对进口处管束的冲击,减缓进口端列管的过早损坏。除了以上优点外,外导流筒还具有温差和压差补偿作用。本文对这种换热器的外导流筒进行理论和模拟研究,用ANSYS有限元分析软件对外导流筒换热器进行温度场分析和结构特性分析,探索其温差补偿能力,并对这种外导流筒进行了强度与应力分析,使外导流筒在具有多功能性质下,仍能保证它的结构可靠性和安全性。在此基础上提出了一种可施加预应力的外导流筒换热器,主要工作包括:1、采用Pro/E软件建立带有外导流筒结构和无外导流筒结构的换热器实体模型,然后将其导入到ANSYS中得到有限元分析模型;2、利用ANSYS有限元分析软件对换热器进行稳态温度场分析,并将温度场分析结果作为温度载荷,再对带有导流筒结构和无导流筒结构的换热器进行热—结构耦合分析,探索外导流筒的温差补偿能力;3、比较外导流筒锥壳在不同半锥顶角下以及外导流筒在不同环壳半径下的热应力情况,找出外导流筒换热器应力分布的主要影响因素;4、将本文的研究结果与前人的实验结果进行了比较,验证本数值分析的可靠性;5、在上述研究的基础上,提出了一种带外导流筒的预应力换热器,并探讨了这种换热器的预应力处理方法和制造方法,对其进行了模拟研究,考察了这种带外导流筒的固定管板式预应力换热器的合理性与可靠性。最终得到的结果是:装有外导流筒的换热器的温差应力可比不装外导流筒的换热器减少百分之二十到百分之三十,而且其温差补偿能力随着外导流筒锥壳半锥顶角的增大而增强。虽然,壳体上有外导流筒后,壳体的柔度增大,但稳定性变小,而本文在壳体上施加预载荷后,制造出的带外导流筒的预应力换热器,除了降低换热器中的温差应力外,还能够使换热器整体处于低应力状态,大大提高了这种换热器的稳定性和安全可靠性。这种多功能外导流筒在一定场合可以取代壳体上的膨胀节,对工程应用具有较好的参考价值。更多还原

【Abstract】 Heat exchanger is a kind of energy-saving equipments which can transfer heat between materials, and it is usually applied in the industries of petroleum, chemistry, metallurgy, electricity and food as well as in the light industry. Along with the rapid development of energy conservation technology, heat exchanger is applied in more fields and has brought about remarkable economic benefits. Among all kinds of heat exchangers, shell and tube heat exchanger is applied mostly . Meanwhile, as the size of the petrochemical equipments is getting larger and larger, heat exchanger with external guide shell is applied more prevalently.Based on the ordinary model of shell and tube heat exchanger, external guide shell heat exchanger has a newly-improved structure on the shell. Generally speaking, external guide shell consists of the following five parts: big cylindrical shell, positive annulated shell, conical shell, negative annulated shell and small cylindrical shells. This kind of structure can make the liquid run through the duct more equably, enlarge the area of heat diffusion, improve the heat-transferring efficiency of the heat interchanger, decrease the power consumption and prevent the liquid’s impact on the tubes at the entrance to slow down the damage.Except for the advantages mentioned hereinbefore, external guide shell possesses more functions such as temperature compensation and prestressed. Based on the ANSYS analyzing software, this thesis is to analyze the temperature field and the structure of external guide shell heat exchanger and to validate its ability to temperature compensation. With the fruits of predecessors, this thesis aims at studying and designing a new model of external guide shell heat exchanger which can be prestressed. The study mainly includes:1. to build up an entity model with external guide shell and without external guide shell by Pro/E software, then input the information to ANSYS in order to build up the analyzing model;2. to use the ANSYS analyzing software to analyze the temperature field of the heat interchanger as well as the therm—struc coupling of both heat interchanger with external guide shell and without external guide shell, to prove external guide shell’s ability to temperature compensation;3. to compare the thermal stresses of conical Shell in different half top angle and annulated shell in different radius, so as to decide the factors which influence the distribution of the stress of external guide shell heat exchanger;4. to verify the reliability of the results of this experiment by comparing it to the studies of predecessors;5. to design a prestressed heat interchanger with external guide shell, analyze its thermal stresses, therefore verify the rationality and practicability of the prestressed heat exchanger with external guide shell.The final result shows that the thermoelectric stress will be reduced by 20% to 30% if the heat interchanger is equipped with a external guide shell, and its ability to equalize the temperature will be enhanced as the half top angle of the conical Shell gets bigger. Meanwhile, as the heat interchanger is equipped with external guide shell, it’s shell becomes softer, as a result preload can be placed on the shell to create a prestress heat interchanger with a external guide shell, which can decrease the thermoelectric stress of the heat interchanger and make the machine stay in a low-stress condition. This kind of multi-functional external guide shell is of certain reference value to the design of heat interchanger.更多还原