鳥越 邦和 ダイキン工業株式会社, 機械技術研究所, 副所長
TAGO Makoto Hokkaido Univ.Fac.Eng., Assistant, 工学部, 助手 (50171682)
YAMADA Masahiko Hokkaido Univ.Fac.Eng., Lecturer, 工学部, 講師 (70230480)
HORIDE Akihiko Hokkaido Univ.Fac.Eng., Assistant, 工学部, 助手 (50229241)
TORIKOSHI Kunikazu Daikin Kogyo Mech.Eng.Lab., Director
|Budget Amount *help
¥9,200,000 (Direct Cost : ¥9,200,000)
Fiscal Year 1992 : ¥1,000,000 (Direct Cost : ¥1,000,000)
Fiscal Year 1991 : ¥2,600,000 (Direct Cost : ¥2,600,000)
Fiscal Year 1990 : ¥5,600,000 (Direct Cost : ¥5,600,000)
An experimental study has been performed to investigate the production characteristics of liquid ice as a new phase change material (PCM) along three horizontal circular cylinders immersed in a cold air stream with spraying droplets of propylene-glycol aqueous solution. The experiments were carried out under a variety of experimental para-meters such as wind velocity, air temperature, and droplet mass flow rate. The test section is 800 mm long and 200 mm X 200 mm in cross section. Three lucite tubes of 25 mm in diameter, on which stainless foil of 50 mum in thickness was wound, were utilized as icing cylinders. The formation of the ice layer along the cylinders were extensively observed. The weight of the liquid ice produced in the wind tunnel were measured. For the present experiments, it was found that the most suitable condition for production of the liquid ice might be obtained.
The experimental apparatus consists basically of a wind tunnel with refrigeration system and spray-genera
tion system. The major components of the wind tunnel are test section, refrigeration system, fan, heaters, a box for collecting liquid ice, associated measuring instrumentations, and ductwork. The refrigeration system was composed of a compressor, driven by a 11.3KW AC motor, with two evaporator and brine-cooled condenser. Seven heaters, which are capable of 8.25 KW, were installed in the tunnel to provide an additional load on the refrigeration system. With these refrigeration system and heaters, the usable temperature range extended from +20 to -20ﾟC. A centrifugal axial fan of 0.75 KW in the wind tunnel was used, which was capable of maximum velocity of 10 m/s in the test section. The test aqueous binary solution was cooled in the reservoir in advance. Solution spray was generated and controlled by a series of nozzles located in the tunnel contraction upstream the test section.
The effect of a variety of parameters such as wind velocity, air temperature, and droplet mass flow rate on the liquid ice production behavior along the cylinders were extensively determined. The following conclusions may be drawn within the range of parameters investigated.
(1) Liquid ice layer formed on the top of the cylinders grows thicker with both decreasing air temperature and increasing wind velocity, and then blockages between the cylinders tend to grow up in short time.
(2) The most suitable condition for production of the liquid ice might be in wind velocity U_a = 6 m/s and air temperature THETA_a = -12ﾟC in the present method.