蒸发冷换热器的实验、仿真与应用研究

发布时间：2018-08-07 06:24

【摘要】：采暖空调能耗占建筑能耗的一半以上，故提高空调系统能效、开发高效的冷热源设备是实现建筑节能的重要途径。蒸发式冷却（简称：蒸发冷）被认为是一种高效冷却方式，且具有节能节材、结构紧凑等优点，在空调用制冷设备中具有良好的应用前景。因此，研究其传热传质特性，优化其参数与结构，对于发展蒸发冷换热器技术具有理论意义和工程实用价值。蒸发冷换热器因其管内流体种类、结构形式和三元换热介质流向不同而具有多种类型，其传热传质现象复杂，故目前主要是针对具体结构的蒸发冷换热器进行实验研究、数值模拟和产品开发，尚缺少通用的蒸发冷数学模型对不同类型的蒸发冷进行模拟分析和结构优化，且对应用逐渐增多的管翅式蒸发冷换热器的研究也非常缺乏。为解决上述问题，本文展开了以下研究工作：（1）搭建了管翅式蒸发冷换热器实验台，研究空气与被冷却介质进口参数对管翅式风冷换热器和蒸发冷换热器性能的影响规律，并根据实验数据拟合出管翅式蒸发冷换热器传质系数关联式；（2）提出了基于空间扫描思想的复杂蒸发冷却式换热器的通用模拟方法，该方法将蒸发冷换热器按空间划分为若干个节点，每个节点视为独立的微型换热器，利用流体在节点之间的流动建立节点联系，根据节点间的能量和质量守恒关系构建迭代算法，通过扫描迭代方法对模型进行求解。在此基础上，通过文献和实验数据对管式、填料式和管翅式蒸发冷换热器计算结果进行验证，结果表明，所建数学模型对各类蒸发冷换热器具有良好的通用性；（3）利用所建立的通用模型分析蒸发式冷却器的分布参数特征以及流体进口状态参数对换热效果的影响，并对管翅式、光管式和填料式蒸发冷换热器进行结构优化及能耗分析，为各类蒸发冷换热器的性能改善指明了改进方向。（4）建立管翅式房间空调器的机组数学模型，分析比较风冷式冷凝器喷水与不喷水时的变工况特性，，结果表明，在风冷式冷凝器上喷水，空调器的制冷季总能耗可降低20%~26%；根据厂家提供的机组性能实验数据构建机组性能模型，研究风冷、水冷、蒸发冷三类冷水机组在不同地区整个制冷季的综合运行性能，蒸发冷冷水机组的节能能效比SEER比风冷式机组提高了13%~30%，比水冷机组提高2%~11%。该工作对蒸发冷制冷机组的产品研发和空调系统的设计选型具有参考价值。
[Abstract]:Heating and air conditioning energy consumption accounts for more than half of the building energy consumption, so improving the energy efficiency of air conditioning system and developing efficient cold and heat source equipment is an important way to achieve building energy saving. Evaporative cooling (evaporative cooling) is considered to be an efficient cooling method with the advantages of energy saving and compact structure. It has a good application prospect in refrigeration equipment for air conditioning. Therefore, it is of theoretical significance and practical value to study the heat and mass transfer characteristics and optimize its parameters and structure for the development of evaporative cooling heat exchanger technology. There are many kinds of heat and mass transfer phenomena in evaporative cooling heat exchangers due to their different types of fluid, structure form and flow direction of ternary heat transfer medium, so the experimental research on evaporative cooling heat exchangers with specific structures is mainly carried out at present. Numerical simulation and product development lack of a general mathematical model of evaporative cooling to simulate and optimize the structure of different types of evaporative cooling and lack of research on the increasing application of tubular fin evaporative cooling heat exchangers. In order to solve the above problems, the following research work has been carried out in this paper: (1) the experimental bench of tubular fin evaporative cooling heat exchanger has been built. The influence of inlet parameters of air and cooled medium on the performance of tube-fin air-cooled heat exchangers and evaporative cooling heat exchangers was studied, and the correlation formula of mass transfer coefficient of tube-fin evaporative cooling heat exchangers was fitted according to the experimental data. (2) A general simulation method of complex evaporative cooling heat exchanger based on spatial scanning is proposed. The method divides evaporative cooling heat exchanger into several nodes according to space, and each node is regarded as an independent miniature heat exchanger. Based on the energy and mass conservation relations between nodes, an iterative algorithm is constructed based on the flow of fluid between nodes, and the model is solved by scanning iterative method. On this basis, the calculation results of tubular, packing and tubular fin evaporative cooling heat exchangers are verified by literature and experimental data. The results show that the mathematical model has good generality for all kinds of evaporative cooling heat exchangers. (3) the distribution parameter characteristics of evaporative cooler and the influence of fluid inlet state parameters on heat transfer efficiency are analyzed by using the established general model. The structure optimization and energy consumption analysis of light tube and packing evaporative cooling heat exchangers are carried out, which points out the improvement direction for the performance improvement of various evaporative cooling heat exchangers. (4) the mathematical model of tube-fin room air conditioners is established. The results show that the total energy consumption of air conditioner during cooling season can be reduced by 20% and 26% when the air-cooled condenser sprays water and does not spray water, the results show that the total energy consumption of the air conditioner can be reduced by 20% and 26% during the season when the air-cooled condenser sprays water on the air-cooled condenser. According to the experimental data of unit performance provided by the manufacturer, the performance model of the unit is constructed, and the comprehensive operation performance of three kinds of chillers, air-cooled, water-cooled and evaporative cooling, in the whole refrigeration season in different regions is studied. The energy efficiency of evaporative cooling chillers is 13 / 30 higher than that of air cooled units, and 2 / 11 higher than that of water cooled water chillers. This work has reference value for the product development of evaporative cooling unit and the design and selection of air conditioning system.
【学位授予单位】：清华大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU83

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