开架式气化器新型传热管强化传热机理研究

发布时间：2018-03-13 03:07

本文选题：气化器　切入点：螺旋扰流杆　出处：《西安石油大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着我国天然气产业的高速发展,对LNG生产工艺也提出了更高的要求。气化器是LNG气化站的核心设备,而我国对其研究与发达国家相比还存在较大差异,尤其是对开架式气化器的传热机理认识尚浅,所有关键设备均从国外进口。因此非常有必要对开架式气化器的强化传热机理进行深入研究,开发出一种国产的新型气化器,以摆脱对国外技术和承包商的依赖。本文在现有超级开架式气化器(SUPERORV)传统结构的基础上,设计了一种新型超级开架式气化器,即在传统气化器传热管内管中加入一个十字螺旋扰流杆。发现扰流杆的存在,不仅能够加强流体的湍流强度,还能有效减小边界层厚度,产生强烈的二次流,加强了流体在径向上的热交换,提高了传热管的换热能力。本文采用数值模拟的手段,对影响换热效果的不同因素(螺距、压力、材质)进行了数值计算分析,结果显示：与目前现行的SUPERORV相比,新型传热管扰流杆的存在,不仅增大了换热面积,还提高了流体的湍流强度,有效破坏了温度边界层,提高了换热管的整体换热能力。在相同雷诺数Re下,新型传热管内流体的平均温度明显高于普通传热管内管流体的温度；当压力为5MPa,雷诺数为6000时,随着螺距的增加,管内流体的湍流度减小,出口处流体平均温度逐渐降低；当在同一雷诺数和螺距时,新型传热管内流体的温度随着压力的升高逐渐降低,且努赛尔数Nu和传热系数h也随其逐渐减小；当依次采用材质不锈钢、铝、铜时,随着雷诺数的增大,新型传热管的努赛尔数Nu也逐渐增大,且采用铜时的努赛尔数最大,传热系数也最大。最后对文献中的实验进行数值模拟,并对比了同一质量流速下不同热流密度对传热的影响,得到了与文献中实验结果相同的结论,验证了数值模拟手段的可靠性和正确性。本文的研究成果为超级开架式气化器国产化提供了一定的理论依据,对实现我国自主研发国产气化器具有一定的工程应用意义。
[Abstract]:With the rapid development of natural gas industry in China, higher requirements have been put forward for LNG production process. Gasifier is the core equipment of LNG gasification station, but the research on it in our country is different from that in developed countries. In particular, the heat transfer mechanism of the open-shelf gasifier is not well understood, and all the key equipments are imported from abroad. Therefore, it is necessary to deeply study the mechanism of enhanced heat transfer of the open-shelf type gasifier and to develop a new type of gasifier made in China. In order to get rid of the dependence on foreign technology and contractors, this paper designs a new type of super open-shelf gasifier based on the traditional structure of the existing super-open-shelf gasifier SUPERORV. It is found that the existence of the spoiler rod can not only enhance the turbulence intensity of the fluid, but also effectively reduce the thickness of the boundary layer and produce a strong secondary flow. The heat exchange of fluid in the radial direction is strengthened and the heat transfer capacity of the heat transfer pipe is improved. In this paper, different factors (pitch, pressure, material) that affect the heat transfer effect are numerically calculated and analyzed by numerical simulation. The results show that compared with the current SUPERORV, the existence of the new heat transfer tube spoiler not only increases the heat transfer area, but also increases the turbulence intensity of the fluid and effectively destroys the temperature boundary layer. Under the same Reynolds number re, the average temperature of the fluid in the new heat transfer tube is obviously higher than that of the ordinary tube fluid, and when the pressure is 5 MPA and the Reynolds number is 6 000, the average temperature of the fluid in the new heat transfer tube increases with the increase of the pitch. At the same Reynolds number and pitch, the temperature of the fluid in the new heat transfer tube decreases with the increase of pressure. The Nussel number Nu and the heat transfer coefficient h also decrease with the increase of Reynolds number, and the Nusselle number of the new heat transfer tube increases with the increase of Reynolds number, and the Nussel number of the new heat transfer tube increases with the increase of the Reynolds number, and the Nussel number of the new heat transfer tube is the largest when copper is used. The heat transfer coefficient is also the largest. Finally, the experiments in the literature are numerically simulated, and the effects of different heat flux on heat transfer under the same mass velocity are compared, and the results are the same as the experimental results in the literature. The research results in this paper provide a theoretical basis for the localization of super open-shelf gasifier, and have a certain engineering application significance for the independent development of domestic gasifier in China.
【学位授予单位】：西安石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE96

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