高温溴化锂溶液导热系数和比热容的实验测定与模型计算
发布时间：2018-11-17 15:05
【摘要】：能源是人类最基本的生产要素之一,随着经济发展,能源消费也在不断增长,整个社会对于能源的依赖程度也越来越大；另一方面,由于大量使用化石燃料而产生的环境污染问题日益突出。采用第二类吸收式热泵将中低温的废热提高到较高品位,在工业余热回收与提高能源利用率方面发挥着重要的作用,受到国内外学者的广泛关注。目前,已经工业化的热泵工质主要为LiBr-H2O工质对,但对高温下LiBr溶液的基础热物性如导热系数、比热容等的研究较少,直接影响了高温热泵的理论研究和应用范围。因此研究LiBr水溶液的高温热物性具有重要学术意义和实用价值。瞬态热线法是目前公认的测量导热系数最准确的方法之一,本文在分析传统瞬态热线法的基础上,对其无法测量导电性溶液的缺点进行改进,以充满汞的石英玻璃毛细管作为热线,新建了瞬态热线法测量液体导热系数的装置,并测量了溴化锂溶液在2MPa压力、150-250℃、质量分数45%-65%下的导热系数,实验结果与文献的最大相对偏差为2.97%。基于绝热量热法新建了溶液比热容的测量装置,测量了溴化锂溶液的比热容,实验结果与文献的最大相对偏差为2.72%。分析了溴化锂溶液导热系数和比热容随温度、组成的变化情况,并对其导热系数和比热容与温度、组成的关系进行了拟合,得出了高低温通用的经验关联式,拟合最大偏差分别为0.35%、1.40%,相对平均偏差分别为0.13%、0.33%。根据电解质溶液理论,建立了溴化锂溶液的导热系数和比热容的模型,模型结果与实验值吻合的较好,最大偏差分别为1.11%和4.93%。
[Abstract]:Energy is one of the most basic factors of human production, with the economic development, energy consumption is also growing, the whole society is more and more dependent on energy; On the other hand, environmental pollution caused by the extensive use of fossil fuels is becoming increasingly prominent. The second kind of absorption heat pump is used to improve the waste heat of middle and low temperature to a higher grade, which plays an important role in industrial waste heat recovery and energy utilization, and has been widely concerned by scholars at home and abroad. At present, the working fluid of heat pump is mainly LiBr-H2O pair, but the basic thermal properties of LiBr solution at high temperature, such as heat conductivity and specific heat capacity, are less studied, which directly affects the theoretical research and application scope of high temperature heat pump. Therefore, it is of great academic significance and practical value to study the high temperature thermal properties of LiBr aqueous solution. The transient hot-wire method is one of the most accurate methods for measuring thermal conductivity. Based on the analysis of the traditional transient hot-wire method, the shortcomings of its inability to measure the conductivity solution are improved in this paper. A new apparatus for measuring the thermal conductivity of liquid by transient hot-wire method was built with a silica glass capillary filled with mercury. The thermal conductivity of lithium bromide solution was measured at 2MPa pressure, 150 ~ 250 鈩，
本文编号：2338221
[Abstract]:Energy is one of the most basic factors of human production, with the economic development, energy consumption is also growing, the whole society is more and more dependent on energy; On the other hand, environmental pollution caused by the extensive use of fossil fuels is becoming increasingly prominent. The second kind of absorption heat pump is used to improve the waste heat of middle and low temperature to a higher grade, which plays an important role in industrial waste heat recovery and energy utilization, and has been widely concerned by scholars at home and abroad. At present, the working fluid of heat pump is mainly LiBr-H2O pair, but the basic thermal properties of LiBr solution at high temperature, such as heat conductivity and specific heat capacity, are less studied, which directly affects the theoretical research and application scope of high temperature heat pump. Therefore, it is of great academic significance and practical value to study the high temperature thermal properties of LiBr aqueous solution. The transient hot-wire method is one of the most accurate methods for measuring thermal conductivity. Based on the analysis of the traditional transient hot-wire method, the shortcomings of its inability to measure the conductivity solution are improved in this paper. A new apparatus for measuring the thermal conductivity of liquid by transient hot-wire method was built with a silica glass capillary filled with mercury. The thermal conductivity of lithium bromide solution was measured at 2MPa pressure, 150 ~ 250 鈩，
本文编号：2338221
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