【作者】 林天轮；

【导师】 杨洪海；

【作者基本信息】 东华大学 ， 供热、供燃气、通风及空调工程， 2011， 硕士

【摘要】 脉动热管具有结构简单、传热性能卓越等优点,是一种新型高效传热原件。设计合理的脉动热管的传热特性不受重力场或极少受重力场的影响。基于脉动热管的此优势,在本课题之前的研究基础上,论文对脉动热管换热器进行改进设计,将其应用于空调排风余能回收系统。建立换热器的性能测试试验台,并对这两种换热器在空调排风余能回收系统中进行性能测试；分析脉动热管换热器的最小启动温差；讨论风速、新排风温差、倾斜角度等因素对其余能回收效率的影响。研究成果包括以下几方面：(1)设计改进了脉动热管换热器。脉动热管由8根增加到40根,相应地弯头数增加了五倍。将其与本课题之前脉动热管换热器的传热性能进行了比较,结果表明：在相同的条件下,本实验脉动热管换热器的换热量较大,其传热性能得到了较大的提高。(2)对于脉动热管换热器,存在一个最小启动温差。在风速2.0-3.0m/s的范围内夏季工况下,得出脉动热管换热器的最小启动温差是2.0℃。(3)影响脉动热管换热器换热效率的因素有风量、蒸发段温度及倾角等。随着排、新风比的增加,换热效率先下降后上升,排、新风比为1时其换热效率达到最低值；随着蒸发段气流的入口温度的增加,其换热效率上升；随着倾斜角度由0°→30°→60°→90°变化时,换热效率是先上升后下降,60°的倾角时其换热效率达到最高值。将本实验脉动热管换热器与重力热管换热器的传热性能进行了比较。结果表明,两者的总体传热特性相似,两种换热器蒸发段和冷凝段气流的进出口温差和效率都随着蒸发段入口的气流温度增加而增加。夏季工况蒸发段气流温度主要集中30-35℃,此温度范围内,脉动热管换热器的换热效率接近重力热管换热器的,而且脉动热管换热器的启动温差要小一些。所以,在空调排风系统能量回收中脉动热管显示出了较大的应用潜力。更多还原

【Abstract】 Pulsating heat pipe (PHP), which is a new type of highly efficient heat transfer original with advantages of simple structure and excellent heat transfer performance. Another advantage of the PHP is that when it is well-designed, its heat transfer performance is little influenced by the gravitaty vector. Based on this good point and previous studies of this topica, the paper improve the design of PHP heat exchanger, using it in air-conditioning exhaust energy recovery systems. The test setup was Designed and built to further study their heat transfer performance in the air-conditioning exhaust heat recovery systems, also the minimum start-up temperature difference was measured. The relationships between the factors (wind velocity, temperature difference between the fresh air and the exhausted air, inelination angle) and the Performance of PHP heat exchanger were analyzed. Here are some research works and conclusions:Firstly, improving the design of PHP heat exchanger. The PHP increases to 40 by the 8 roots, corresponding to five-fold increase in the number elbow. We compared it with the PHP heat exchanger of previous studies of this topica on their heat transfer performence. Results show that, the PHP heat exchanger has more heat transfer and its heat performance is greatly improved in the same conditionsSecondly, it has minimum activated temperature difference for the PHP heat exchanger. It is found that the wind velocity is in the range of 2.0-3.0m/s, the minimum start-up temperature difference between hot and cold air is 2℃for the PHP heat exchanger in summer condition.Thirdly, there has some influencea factors for heat transfer Performance of PHP heat exchanger, such as wind velocity, the evaporator air temperature and inelination angle. The effectiveness become smaller at first and after it reaches the smallest point it became bigger with increasing of the rate ratio between return and fresh air, and the smallest point was at the 1 rate ratio. With the evaporator air temperature increasing, the efficiency is increasing. Its effectiveness become bigger at first and after it reaches the biggest point it became smaller with increasing of inelination angle (from 0°、30°、60°to 90°), and the biggest point was at the 60°inelination angle. We compared PHP heat exchanger with the thermosyphon heat exchanger on their heat transfer performence. Results show that both types of heat exchangers showed the similar heat transfer characteristics generally. With the evaporator air temperature increasing, air temperature difference between imports and exports and the efficiency also increases, both for evaporation section and condensation section. The evaporation section air temperature between 30-35℃usually in summer conditions, data shows that the PHP minimum start temperature is smaller in this range. Therefore, the PHP heat exchangers in air-conditioning exhaust heat recovery system exist a lot of potential applications.更多还原