| Budget Amount *help |
¥7,400,000 (Direct Cost: ¥7,400,000)
Fiscal Year 1988: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1987: ¥5,900,000 (Direct Cost: ¥5,900,000)
|
|---|
| Research Abstract |
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
|
