导湿织物对间接蒸发冷却器亲水性和热性能影响的实验研究

Experimental Study of Effects of Moisture-conducting Fiber on Hydrophilic and Thermal Performance of Indirect Evaporator Cooler

为了提高间接蒸发冷却器湿通道的亲水性和蒸发速率,避免局部干点或水膜过厚的问题,提出将导湿织物敷设于湿通道的壁面,研究了其亲水性和热性能。亲水性能的实验首先测定了织物的芯吸高度和湿扩散速率,再通过搭建芯体布水实验台,并采用数字图像处理法,研究了喷淋时间(5s~180s)、喷淋流量(2L/min~6L/min)以及喷嘴高度(50mm~250mm)对芯体中三个典型位置的敷布铝板表面润湿率的影响。利用导湿织物的保水性,探究了间歇喷淋下(喷淋15s,间隔15min)湿通道的热性能。结果显示:随着喷淋时间、喷淋流量、喷淋高度的增加,边缘板的润湿率显著增加,之后达到稳定。在喷射角为58°、喷淋流量为5L/min、喷淋高度为100mm~150mm的工况下,芯体喷淋30秒后可达到完全润湿。间歇喷淋下出口温度和壁温均呈周期性变化,性能系数(COP)是连续喷淋下的6.52倍。说明导湿织物配合间歇喷淋可以显著改善湿通道亲水性并大幅提升能效。研究结果对亲水型间接蒸发冷却器的高效运行和设计具有一定的指导意义。

To improve the hydrophilicity and evaporative rate of the wet channels of an indirect evaporative cooler(IEC),and avoid the problems of local dry regions and thick water film,the hydrophilic and thermal performance of an IEC with moisture-conducting fabric attached to the wet walls are studied.In the experiment of hydrophilicity,the wicking height and diffusion rate were firstly tested.Then,the influences of spray time(5s~180s),spray flow rate(2L/min~6L/min)and nozzle height(50mm~250mm)on the surface wetting rate of the coated aluminum foil at three typical positions in the core were studied by setting up a core water distribution experimental platform and combing with digital image processing.Owing the water storage of fabric,the thermal performance of wet channels under the intermittent spray(spray period:15s,interval:15min)was investigated.The results show that with the increase of spray time,spray flow rate and spray height,the wetting ratio of the outmost plates’surface increases obviously and then reaches a steady state.Under the conditions of spray angle of 58°,spray flow of 5L/min and spray height of 100mm-150mm,the core reaches fully wet after 30s spraying.The outlet air and surface temperatures vary periodically,and Coefficient of Performance is 6.52 times of that under continuous spraying,indicating that the fabric can greatly enhance the wettability and improve the energy efficiency.The research results provide references for the design and operation of a hydrophilic IEC.