【作者】 李巧珍；

【导师】 罗敏；

【作者基本信息】 东北石油大学 ， 工程力学， 2011， 硕士

【摘要】 真空加热炉以其造价低、能耗低、效率高、自动化程度高等优势已成为目前油田传统加热炉的理想换代产品,因而其安全性也更加引起人们的关注。全面考虑炉管的工作环境(即管内、外流体)对炉管力学行为的影响,具有较高的应用价值。本文根据数值传热理论与热应力理论,验证了分别采用流体计算软件CFX和有限元分析软件ANSYS对结构进行共轭传热分析与热应力分析的正确性。在对多场耦合分析模型选取的问题上,本文利用CFX软件中的GGI(界面网格)法则,通过对耦合界面网格匹配与不匹配两种模型进行计算,对大型复杂结构采用耦合界面网格不匹配模型来进行数值模拟。在上述验证分析的基础上,根据炉管的实际工作状态,分别建立了三种炉管结构(直管段、弯管段、盘管)、管内流体、环空流体以及筒体的三维有限元力学分析模型。考虑界面力及温度传递,综合利用ANSYS软件和CFX软件,实现了对加热炉炉管的多场耦合数值模拟。又研究了管内流体的粘度和流速对盘管多场耦合效应的影响。结果表明:当粘度较小时,传热系数随着流速的升高而升高,且变化幅度较大;当粘度较大时,传热系数随着流速的升高而升高,但是变化幅度较小。随着粘度和流速的增加,盘管等效应力、总位移最大值所受的影响均较小。即管内流体粘度、流速对共轭传热分析影响明显,对多场耦合效应的影响不明显。本论文研究成果,更加科学地描述了加热炉炉管的力学特性,为加热炉合理设计和安全评定提供新的研究方法。同时,多场耦合数值模拟方法也可应用于石油化工、钻井采油等领域相关设备的分析研究中。更多还原

【Abstract】 Due to the adcantaces of low cost, low energy consumption, high efficiency and high degree of automation, vacuum Furnace has become the ideal replacement of traditional oil heating ,whose security was much more concerned by people. Full account of how the working environment of tube (ie tube inside and outside the fluid) influence the mechanical behavior of tube has a high engineering value for doing the force analysis accurately.In this paper, basing on the theories of numerical heat transfer and thermal stress, the correctness of doing the conjugate heat transfer analysis and thermal stress analysis for structure by ANSYS software and CFX software was verified separately. On the question of how to select the model for the multi-field coupling analysis, the simulations of the coupling interface with the grid matching and not matching was done by using the GGI (interface grid) rules of CFX software, we obtain the conclusion that the not matching grid model will be choosed when the structure is large and complex.On the base of the above check analysis, the three-dimensional finite element analysis model of the three structural furnace tubes(straight pipe, bend pipe and coils), inner fluid, annulus fluid and the tube structure was established by considering its actual working conditions. Considering the interface strength and temperature transfer, the numerical simulation of multi-field coupling for Furnace tube was done by the ANSYS software and the CFX software. And then, how the viscosity and velocity of the fluid tube effect the coil was studied. The results show that:when the viscosity is low, the higher the velocity, the higher the heat transfer coefficient and the larger the amplitude becomes; when the viscosity is high, the higher the velocity, the higher the heat transfer coefficient and the smaller amplitude becomes. With the increase of the fluid rate and viscosity, the coil equivalent stress and the maximum displacement almostly not be influenced. It is that : the tube fluid viscosity and flow rate have a great effect on the conjugate heat transfer analysis ,but the effect on the multi-field coupling is not obvious.The results of this thesis give a more scientific description for the mechanical properties of furnace tube, offering a reasonable design and safety assessment of new research methods for the furnace. At the same time,the method of numerical simulation of multi-field coupling can also be used in the study of petrochemical, drilling and other related equipment.更多还原