顶置蓄冷板减少融霜热对冷库温度场影响的研究

发布时间：2018-02-07 10:25

  本文关键词： 冷库 双蒸发器 热气融霜 蓄冷　出处：《天津商业大学》2017年硕士论文　论文类型：学位论文

【摘要】：冷库运行一段时间后,制冷系统中的蒸发器出现结霜现象,结霜严重时会造成蒸发器的蒸发能力降低,能耗大幅度增加等各种恶劣的影响,所以必须要求除霜。目前常用的除霜方式有电热除霜和热气除霜,不管用何种除霜方法,总会有大部分热量散到冷库周围环境,这不但使能量有所损失,而且还破坏了周围的温度场。为保证食物储藏的品质,本课题着眼于降低冷库温度波动的蓄冷装置的研究。本课题从理论上分析了霜的结构,霜的物性参数和蒸发器性能参数,然后重点对冷库进行理论分析计算,针对空库状态下连续融霜过程中库温波动计算得到最大可能需要的蓄冷量;利用Fluent对带蓄冷装置的冷库在连续融霜过程中的气流场进行模拟计算,然后分析结果,用实验值验证模拟值的可靠性;最后开始冷库降温实验,将冷库温度场维持在-18±0.5℃半小时左右,使冷库温度场达到稳定状态,当冷库达到除霜要求时开始除霜,分析研究冷库有无蓄冷板时在制冷风机有无霜层的工况下在0m,0.7m,1.4m,2m处的截面温度,冷库整体温度,1号2号风机中轴线位置处蓄冷板底部温度和融霜能耗等。研究结果表明:除霜过程中,安装蓄冷板的冷库各截面温度均低于空库温度;制冷风机有霜状态下,安装蓄冷板整体库温波动比空库温度波动减小2.48℃,融霜能耗增加1.36%,可以忽略不计蓄冷板的安装对融霜能耗的影响;制冷风机无霜状态下,安装蓄冷板整体库温波动比空库温度波动减小2.92℃,融霜能耗增加1.81%,同样可以忽略不计蓄冷板对融霜能耗的影响;制冷风机中轴线位置处蓄冷板底部的温度在远离风机位置处越高,融霜风机中轴线位置处蓄冷板底部的温度在远离风机位置处越低。通过实验对比得,冷库顶部安装蓄冷板能够有效降低冷库连续融霜过程中的冷库温度波动。这样双蒸发器融霜过程中库顶安装的蓄冷装置既减小了冷库内温度波动,又保证了冷库内湿度的恒定。
[Abstract]:After the cold storage operation for a period of time, the evaporator in the refrigeration system appears frosting phenomenon, when frosting is serious, the evaporator evaporation ability will be reduced, the energy consumption will be greatly increased and other bad effects. So defrosting must be required. At present, the commonly used defrosting methods are electrothermal defrosting and hot gas defrosting. No matter what kind of defrosting method is used, most of the heat is always dispersed into the surrounding environment of the freezer, which not only results in a loss of energy, In order to ensure the quality of food storage, this project focuses on the research of the cold storage device to reduce the temperature fluctuation in the cold storage. The structure of the frost, the physical parameters of the frost and the performance parameters of the evaporator are analyzed theoretically. Then, the theoretical analysis and calculation of the cold storage are carried out, and the maximum amount of cold storage is obtained according to the fluctuation of the reservoir temperature in the process of continuous defrosting under the condition of empty storage. Fluent is used to simulate the airflow field of a cold storage tank in the process of continuous defrosting, then the results are analyzed, and the reliability of the simulated value is verified with the experimental value. Finally, the cold storage cooling experiment is started. If the temperature field of the cold storage is maintained at -18 卤0.5 鈩，

本文编号：1494158