某超长重力热管提取地热的模拟及分析

发布时间：2018-01-13 17:27

本文关键词：某超长重力热管提取地热的模拟及分析　出处：《西安工程大学》2016年硕士论文　论文类型：学位论文

【摘要】：超长重力热管提取地热装置是利用热管的优点建立起来的试验装置,但是在运行过程中并没有取得良好的效果。本文采用FLUENT模拟软件对3000m的超长重力热管提取地热装置进行模拟,研究分析其中的不足之处并加以改进,并对改进后的装置再次进行模拟,为改进后重力热管的运行提供较可靠的预测,为超长重力热管的改进提供理论性指导。主要研究内容为:(1)回顾了重力热管内的对流换热机理,介绍了超长重力热管的工作原理,并在此基础上总结了超长重力热管与普通重力热管的区别与联系。(2)采用计算流体力学软件(Computational Fluid Dynamics,简称CFD)中的FLUENT商业软件,对超长重力热管进行数值模拟。首先,使用Gambit前处理软件对热管进行建模和划分网格。其次,在FLUENT中进行边界条件的设置,应用流体体积函数(volume of fluid,简称VOF)模型计算重力热管内两相流的流动与换热情况,由于FLUENT中没有提供蒸发与冷凝模型,所以使用用户自定义函数(User-Defined-Function,简称UDF)定义蒸发与冷凝源项,进而计算蒸发与冷凝过程。模拟结果显示,蒸气上升至2693m处出现凝结现象,蒸气的上升距离约为520m。(3)对超长重力热管的优化设计,根据得到的模拟结果,对超长重力热管提取地热装置在以下几个方面进行改进:1)强化沸腾换热;2)绝热段的绝热处理;3)液体工质的回流;4)真空机的放置。(4)对改进后的重力热管进行数值模拟,根据得到的结果,对改进后热管的运行情况及蒸气的产量进行预测,以推断重力热管的改进方案是否可行。得到改进后的重力热管的出口处重力热管内的蒸气产量明显增多。
[Abstract]:The super-long gravity heat pipe extraction device is a test device based on the advantage of heat pipe. However, no good results have been achieved in the process of operation. In this paper, FLUENT simulation software is used to simulate the geothermic equipment of 3000m super-long gravity heat pipe extraction. The shortcomings are analyzed and improved, and the improved device is simulated again, which provides a reliable prediction for the operation of the improved gravity heat pipe. This paper reviews the convection heat transfer mechanism in the gravity heat pipe and introduces the working principle of the super long gravity heat pipe. On this basis, the difference and relation between super long gravity heat pipe and ordinary gravity heat pipe are summarized. Computational Fluid Dynamics. The FLUENT commercial software in CFDs is used to simulate the super-long gravity heat pipe. Firstly, the Gambit pre-processing software is used to model and mesh the heat pipe. The flow and heat transfer of two-phase flow in gravity heat pipe are calculated by using the volume of fluid volume of fluid model in FLUENT. Because the evaporation and condensation model is not available in FLUENT, the user-defined function is used to define the User-Defined-Function. UDF defines the source term of evaporation and condensation and then calculates the process of evaporation and condensation. The simulation results show that condensation occurs at 2693 m. The rising distance of steam is about 520m.m3) the optimum design of super long gravity heat pipe is obtained according to the simulation results. In this paper, the superlong gravity heat pipe extraction device is improved in the following aspects: 1) enhanced boiling heat transfer; 2) adiabatic heat treatment; 3) reflux of liquid working fluid; 4) the vacuum machine is placed. (4) numerical simulation of the improved gravity heat pipe is carried out. According to the results obtained, the operation of the improved heat pipe and the output of steam are predicted. In order to infer whether the improved scheme of gravity heat pipe is feasible or not, the steam production in gravity heat pipe at the outlet of the improved gravity heat pipe is obviously increased.
【学位授予单位】：西安工程大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TK172.4

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