基于烟气余热回收蓄热装置的数值模拟
发布时间：2018-09-01 20:17
【摘要】：随着工业的飞速发展和人类生活水平的提高,能源需求量一直处于上升趋势。由于不合理的开采和利用,能源短缺问题已在全球范围内出现,但能源浪费现象依然十分严重,因此采用合理有效的方法提高能源利用率显得尤为重要。储能技术可以将太阳能、工业余热等以热能的形式储存起来,缓解能源供给与使用之间存在的空间和时间差问题,成为提高能源利用率的有效手段。储能技术的研究主要包括对储热材料和储热装置结构的研究。由于大部分的储热材料热导率不高,使得储热装置整体传热效率较低,因此寻求合适的强化传热手段以提高系统充放热效率很重要。本文选取中高温储热材料中常见的NaNO3-46KNO3、LiNO3、己二酸作为相变储热材料,组建相应的蓄热装置结构,研究装置的传热特性和强化传热效果。为提高系统整体传热效率,针对装置中烟气热导率较低的问题,分别设计了盘管式和波纹管式两种蓄热装置。盘管结构能在较小的尺寸范围内延长烟气的行驶路径,增加接触时间,提高传热速率;波纹管结构能增大换热接触面积、增强流体扰动以强化传热,且相变材料的体积填充比大,材料利用率高。建立了盘管式余热回收蓄热装置结构模型,根据理论计算经验公式,初步确定了结构单元特征和尺寸,简化模型后进行三维建模,利用Fluent软件对蓄热装置的放热过程进行数值模拟研究,模拟换热过程中蓄热装置内的温度场分布、液相率分布,各监测点监测面的温度变化等,分析了不同导热油入口流速、蓄热装置初始温度和自然对流对系统充放热性能的影响,得出最佳的工况条件。计算了相变材料选用NaNO3-46KNO3和LiNO3时的装置蓄热量分别为0.481MWh和0.508MWh。根据结构中相关部件的合理化分析,对蓄热装置中各单元结构和尺寸进行优化,为盘管式蓄热装置的实际应用提供参考。建立了波纹管式蓄热装置的单管二维数学模型,与相应尺寸光管单元模型的充放热过程进行对比分析,比较波纹管的强化传热效果。并在25mm管径条件下,模拟了充放热过程中储热单元温度场分布、相界面移动规律、监测点温度变化趋势和相变材料蓄热量等,分析了不同波节间距和波节高度对蓄热单元充放热性能的影响,得到最佳波节高度和波节间距尺寸参数。经过计算得到在最佳结构参数下的波纹管蓄热装置整体蓄热量为66978kJ,为波纹管式余热回收蓄热装置在工程实际中的应用提供一定的参考价值。
[Abstract]:With the rapid development of industry and the improvement of human living standards, energy demand has been on the rise. Because of unreasonable exploitation and utilization, the problem of energy shortage has appeared all over the world, but the phenomenon of energy waste is still very serious, so it is very important to adopt reasonable and effective methods to improve energy efficiency. Energy storage technology can store solar energy and industrial waste heat in the form of heat energy, alleviate the space and time difference between energy supply and use, and become an effective means to improve energy efficiency. The research of energy storage technology mainly includes the research of heat storage material and heat storage device structure. Due to the low thermal conductivity of most heat storage materials, the overall heat transfer efficiency of the heat storage device is low, so it is very important to find suitable means to enhance the heat transfer efficiency of the system. In this paper, NaNO3-46KNO3,LiNO3, adipic acid, which is common in medium and high temperature heat storage materials, is selected as phase change storage material, and the corresponding heat storage device structure is constructed to study the heat transfer characteristics and enhanced heat transfer effect of the device. In order to improve the overall heat transfer efficiency of the system, two kinds of heat storage devices, coil type and corrugated tube type, were designed to solve the problem of low thermal conductivity of flue gas in the device. The coil structure can prolong the running path of flue gas, increase the contact time and increase the heat transfer rate in the small size range, and the corrugated tube structure can increase the heat transfer contact area and enhance the fluid disturbance to enhance the heat transfer. The volume filling ratio of phase change material is large and the material utilization ratio is high. The structure model of coil type waste heat recovery and storage device is established. According to the empirical formula of theoretical calculation, the characteristics and dimensions of the structure unit are preliminarily determined, and the three-dimensional modeling is carried out after simplifying the model. The heat release process of heat storage device is simulated by Fluent software. The temperature field distribution, liquid phase rate distribution and temperature change of monitoring surface in the heat storage device during heat transfer process are simulated, and the inlet velocity of different heat conduction oil is analyzed. The effects of the initial temperature and natural convection of the heat storage device on the system's heat filling and releasing performance are discussed. The optimal operating conditions are obtained. The heat storage of the device with NaNO3-46KNO3 and LiNO3 is calculated as 0.481MWh and 0.508MWh. respectively. According to the reasonable analysis of the relative parts in the structure, the structure and size of each unit in the heat storage device are optimized, which provides a reference for the practical application of the coil type heat storage device. The two-dimension mathematical model of the corrugated tube type heat storage device is established. The heat transfer enhancement effect of the corrugated tube is compared with that of the corresponding size light tube unit model. Under the condition of 25mm pipe diameter, the temperature field distribution of heat storage unit, the law of phase interface movement, the temperature change trend of monitoring point and the heat storage of phase change material during heat filling and exothermic process are simulated. The effects of different pitch spacing and pitch height on the heat storage unit are analyzed and the optimum parameters of pitch height and pitch size are obtained. The overall heat storage capacity of the corrugated tube heat storage device under the optimum structural parameters is 66978kJ, which provides a certain reference value for the application of the corrugated tube heat recovery device in engineering practice.
【学位授予单位】：武汉理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB34;TK115
本文编号：2218237
[Abstract]:With the rapid development of industry and the improvement of human living standards, energy demand has been on the rise. Because of unreasonable exploitation and utilization, the problem of energy shortage has appeared all over the world, but the phenomenon of energy waste is still very serious, so it is very important to adopt reasonable and effective methods to improve energy efficiency. Energy storage technology can store solar energy and industrial waste heat in the form of heat energy, alleviate the space and time difference between energy supply and use, and become an effective means to improve energy efficiency. The research of energy storage technology mainly includes the research of heat storage material and heat storage device structure. Due to the low thermal conductivity of most heat storage materials, the overall heat transfer efficiency of the heat storage device is low, so it is very important to find suitable means to enhance the heat transfer efficiency of the system. In this paper, NaNO3-46KNO3,LiNO3, adipic acid, which is common in medium and high temperature heat storage materials, is selected as phase change storage material, and the corresponding heat storage device structure is constructed to study the heat transfer characteristics and enhanced heat transfer effect of the device. In order to improve the overall heat transfer efficiency of the system, two kinds of heat storage devices, coil type and corrugated tube type, were designed to solve the problem of low thermal conductivity of flue gas in the device. The coil structure can prolong the running path of flue gas, increase the contact time and increase the heat transfer rate in the small size range, and the corrugated tube structure can increase the heat transfer contact area and enhance the fluid disturbance to enhance the heat transfer. The volume filling ratio of phase change material is large and the material utilization ratio is high. The structure model of coil type waste heat recovery and storage device is established. According to the empirical formula of theoretical calculation, the characteristics and dimensions of the structure unit are preliminarily determined, and the three-dimensional modeling is carried out after simplifying the model. The heat release process of heat storage device is simulated by Fluent software. The temperature field distribution, liquid phase rate distribution and temperature change of monitoring surface in the heat storage device during heat transfer process are simulated, and the inlet velocity of different heat conduction oil is analyzed. The effects of the initial temperature and natural convection of the heat storage device on the system's heat filling and releasing performance are discussed. The optimal operating conditions are obtained. The heat storage of the device with NaNO3-46KNO3 and LiNO3 is calculated as 0.481MWh and 0.508MWh. respectively. According to the reasonable analysis of the relative parts in the structure, the structure and size of each unit in the heat storage device are optimized, which provides a reference for the practical application of the coil type heat storage device. The two-dimension mathematical model of the corrugated tube type heat storage device is established. The heat transfer enhancement effect of the corrugated tube is compared with that of the corresponding size light tube unit model. Under the condition of 25mm pipe diameter, the temperature field distribution of heat storage unit, the law of phase interface movement, the temperature change trend of monitoring point and the heat storage of phase change material during heat filling and exothermic process are simulated. The effects of different pitch spacing and pitch height on the heat storage unit are analyzed and the optimum parameters of pitch height and pitch size are obtained. The overall heat storage capacity of the corrugated tube heat storage device under the optimum structural parameters is 66978kJ, which provides a certain reference value for the application of the corrugated tube heat recovery device in engineering practice.
【学位授予单位】：武汉理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB34;TK115
【参考文献】
相关期刊论文 前10条
1 王霞;王利恩;;熔融盐储热技术在新能源行业中的应用进展[J];电气制造;2013年10期
2 邓静;;回转窑高温烟气余热的回收利用[J];科技风;2013年09期
3 付路军;董发勤;杨玉山;何平;;二元脂肪酸/SiO_2复合相变储能材料的制备与表征[J];功能材料;2013年04期
4 凌空;封永亮;陶文铨;;带环状翅片管式相变储热器的数值模拟[J];工程热物理学报;2012年08期
5 周卫兵;张磊;朱教群;孙正;程晓敏;;硬脂酸/膨胀石墨复合相变储热的动力学研究[J];武汉理工大学学报;2012年07期
6 李元元;程晓敏;俞铁铭;;Sn-Zn合金相变储热材料的热循环稳定性[J];特种铸造及有色合金;2012年07期
7 白松;;单管程浮头换热器中波形膨胀节的设计[J];石油化工设备技术;2012年01期
8 郭茶秀;刘树兰;;固-液相变传热强化过程研究进展[J];广州化工;2011年12期
9 李利民;庄春龙;张洪宇;邓安仲;李胜波;;焓法模型求解相变传热问题有效性分析[J];后勤工程学院学报;2011年03期
10 李丽莎;闫全英;;相变围护结构的研究及发展[J];材料导报;2010年S2期
相关硕士学位论文 前2条
1 俞铁铭;Sn-Bi-Zn-Cu-Pb多元合金中温相变储热性能研究[D];武汉理工大学;2012年
2 欧阳梅;针翅管式相变蓄热换热性能的数值模拟[D];重庆大学;2009年
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