A Study of Heat-Transfer Performance of Insulation Material Available in Cold Climates With De-Frosting Function

本文通过实验研究了空气流速、空气温度和冷却壁温度对玻璃棉绝热层的热流特性、贮水率和等效导热系数的影响。本实验装置由实验段、空气循环系统、冷盐水循环系统、温度补偿室及相关仪器组成。试验材料为高1000 mm、深300 mm、厚100 mm、密度16 kg/m^3的玻璃棉。为了测量玻璃棉内的温度，将6个C-A热电偶安装到材料中。冷却壁由3mm厚的铜板制成。通过将温度受控的盐水从位于壁背面的管组的喷嘴孔散布，来均匀地保持冷却壁表面的温度。移民局之间的恩怨 ...更多信息 B.采用电加热器使室内温度保持均匀，用加湿器控制室内湿度。结果和讨论在本研究所涵盖的参数范围内可以得出以下结果。(1)玻璃棉内的储存水分含量随着间隙中气流速度的增加而减少。当空气温度为5 ℃，冷却壁温度为-15 ℃时，U = 1.0 m/s时的贮水率约为U = 0.2 m/s时的1/3。(2)通过玻璃棉的热流特性随气流温度的变化而显著变化，当T_a = 5 ℃时，热流随气流速度的增加而单调增加，而当T_a = 10 ℃时，热流随气流速度的增加而单调减少。(3)气流温度对等效导热系数的影响具有特殊性，低温气流使等效导热系数随气流速度的增大而增大。(4)进气温度是影响玻璃棉传热性能的重要参数。(5)需要进行额外的研究，以使用实际的进气温度更准确地确定通过冷却壁和隔热层之间的清灰器的空气流的影响。少

An experimental investigation has been conducted to determine the effect of air velocity, air temperature, and cooled-wall temperature on the heat-flow characteristics through the glass-wool insulation, the storaged moisture content, and the equivalent thermal conductivity.A. Experimental Apparatus and Arocedures The present experimental apparatus consists of test section, air circulating system, cooled-brine circulating system, temperature-compensating room, and associated instrumentations. Glass wool of 1000 mm in hight, 300 mm in depth, 100 mm in thickness with 16 kg/m^3 in density was used as a testing material. To measure the temperature within the glass wool, 6 C-A thermocouples were installed into the material. The cooled wall was made up of copper plate 3 mm in thickness. Temperature of the cooled-wall surface was maintained uniformly by spreading the temperature-controlled brine from the nozzle holes of the pipe set at just backside of the wall. The clear-lance between the ins … More ulation and the cooled wall was 20 mm. Temperature of the room was uniformly kept by use of electric heaters, while the humidity of the room was controlled by a humidifier.B. Results and Discussion The following results may be drawn within the parameters covered in the present study. (1) The stored moisture content within a glass wool decreases with an increase in air-flow velocity in the clearance. For air temperature of 5 C and cooled-wall temperature of -15 C, the storaged moisture content at U = 1.0 m/s is about 1/3 times as large as that at U = 0.2 m/s. (2) The heat-flux characteristics through the glass wool change markedly with the value of air-flow temperature; for T_a= 5 C the heat flux increases monotonically with increasing air velo-city, while for T_a= 10 C the heat flux decreases monotonically with increasing air velocity. (3) The equivalent thermal conductivity behavior is influenced peculiarly on the air-flow temperature; low temperature air flow causes an increase of the equivalent thermal conductivity with an increase in air velocity. (4) Inlet air temperature is a most important parameter which may controll markedly the heat-transfer characteristics through the glass wool in the present system. (5) An additional study is required to more exactly determine the effect of the air flow through the clearlance between the cooled wall and the insulation using an actual inlet air temperature. Less