【作者】 董静；

【导师】 程晓敏；

【作者基本信息】 武汉理工大学 ， 材料学， 2009， 硕士

【摘要】 热能储存是太阳能热发电技术的关键,也是解决能源问题的核心技术,目前正受到广泛的研究关注。储热材料的选择关系到热能储存的效率与效果,金属相变储热材料储热量高,稳定性好,广泛应用于高温储热,因此成为本文研究的出发点。本文基于Al-Si-Cu-Mg-Zn合金优良的储热性能,对材料进行成分的优化设计,使其在储热量、相变温度范围方面更加适应太阳能热发电系统的实际工作需要。本文共设计制备了Al-Cu类、Al-Si-Cu类、Al-Cu-Mg类、Al-Cu-Zn类四类合金共12个试样,通过相图分析、等离子光谱分析、金相显微分析、X射线衍射分析、差示扫描量热分析、基于阿基米德原理的排液法等分析测试方法,对试样的元素含量、金相组织、物相结构、潜热、密度进行分析与测量,并依据奈曼-柯普定律完成显热计算。结合潜热与显热以全面评价材料的储热能力,且通过密度将单位质量储热量换算为单位体积储热量,以便在有限的储热室空间里更直观地评价材料储热能力。根据测试与计算结果,本文所制备的12种铝基合金相变储热材料的储热量均大于900J/cm~3,相变温度范围为450～650℃,可用作太阳能热发电系统的储热材料。储热材料单位质量相变潜热受元素热焓值和物相组织热焓值的影响。受元素热焓值影响,Al-Cu类合金储热材料单位质量相变潜热比其余三类高,Al-Cu-Mg类合金其次;受物相组织热焓值影响,Al-Cu类中的B2合金具有最高的单位质量相变潜热值。材料的显热主要跟各组成元素的比热容及其含量有关,Al-Cu类合金的单位质量显热比其它三类要高,且B1合金显热最高。计算发现各合金显热值较可观且差值较小。结合潜热及显热来分析合金的单位质量总储热量,Al-Cu类合金的显热和潜热均高于其它三类,综合储热能力最佳;尽管Al-Cu-Mg类合金具有较高潜热值,但其显热最差,故总储热量不佳。通过添加Cu、Zn元素可增大材料密度,从而极大地提高材料单位体积总储热量。因此,Al-Cu类、Al-Cu-Zn类合金具有较大的单位体积储热量。综合所制备的材料来看,Al-Cu类中的B2合金在单位体积储热能力上表现最佳,且相变温度范围为549.2～559℃,适用于太阳能热发电系统。更多还原

【Abstract】 Thermal storage is the key of solar thermal power generation technologies, and also is the core technology to solve energy problems, currently is under extensive research attention. The choice of thermal storage material is greatly related to the efficiency and effectiveness of thermal energy storage. The metal phase change thermal energy storage materials has high Heat reservoir, good stability, is widely used in high temperature heat storage, has therefore become the starting point of this study. Based on the excellent heat storage properties of Al-Si-Cu-Mg-Zn alloys, the material compositions were optimally designed to make them more responsive to the actual work requirements of solar thermal power generation system in the aspects of heat storage and phase change temperature range.In this article, 12 kinds of alloys belonged to four series , such as Al-Cu alloys, Al-Si-Cu alloys, Al-Cu-Mg alloys, Al-Cu-Zn alloys, were designed and prepared. Through test methods, such as phase diagram analysis, plasma spectral analysis, metallographic microscopy analysis, X-ray diffraction analysis, differential thermal analysis,and fluid-discharge therapy based on Archimedes principle, the element content, microstructure, phase structure,latent heat, density of samples can be tested,and the sensible heat can be caculated according to Neumann - Kopp Rule. Latent heat and sensible heat should be combined to comprehensively evaluate the heat storage capacities of materials, and heat storage quantity per unit mass can be converted into per unit volume through density, so that we can get a more intuitive evaluation of thermal storage capacity in a limited space of thermal storage room. According to the test and calculation results, the 12 kinds of materials prepared in this paper, whose heat reservoirs are bigger than 900J/cm~3 and phase change temperature ranges are between 400 - 650℃, can be used as thermal storage material in solar thermal power generation system.Latent heat of Thermal storage material per unit mass was greatly effected by the enthalpy values of elements and phase structures. Affected by the former effect, Al-Cu series alloys got the highest latent heat per unit mass than the other three series alloys, and Al-Cu-Mg series alloys was followed by them; affected by the latter, as a kind of Al-Cu series alloys, B2 sample had the highest latent heat per unit mass.The sensible heat of samples mainly related with the specific heat capacity and content of constituent elements. The sensible heat of Al-Cu series alloys per unit mass is higher than the other three series alloys, and sample B1 has the highest value. According to calculation, sensible heat of each sample was impressive and only has small difference.Combined latent heat and sensible heat to analyze the overall thermal storages of samples per unit mass. Al-Cu series samples got the best performance of sensible heat and latent heat, so the integrated heat storage were the best. Despite that Al-Cu-Mg samples had the highest latent heat value, its sensible heat were the worst, so the total storage heat were poor.By adding Cu, Zn element to increase materials’ density, the total heat storage per unit volume of materials were greatly increased. Al-Cu series and Al-Cu-Zn series samples got the largest heat reservoir per unit volume.Sum up materials prepared in this paper, as a kind of Al-Cu alloys, B2 sample had the best thermal storage capacity performance per unit volume, and its phase change temperature range were 549.2-559℃, which can apply to solar thermal power generation systems.更多还原