An Experiment on Heat Transmission between Hot and Cold Rooms using a Scale Model Filled with Freon Gas R114

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  • 隔壁を介した建物内二室間の熱移動に関するフロンガス(R114)による小型模型実験
  • 隔壁を介した建物内2室間の熱移動に関するフロンガス(R114)による小型模型実験
  • カクヘキ オ カイシタ タテモノナイ 2シツカン ノ ネツ イドウ ニ カンス

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An experimental study of free convection heat transfer along a vertical partition between a hot room and a cold room in a house has been carried out using a one fifth scale model filled with Freon gas R114. The results of the visualization of free convective flow along the partition, the vertical temperature distributions of the fluid and the partition, the grade of temperature stratification of the fluid, and the vertical distributions of heat flux across the partition and local heat transfer coefficient on the partition are presented and compared with those for air, which were obtained from the same experimental apparatus. In both cases of R114 and air, the vertical temperature distribution of the fluid and the partition are symmetric with respect to the central horizontal line of the apparatus, and are nearly linear except the regions near the floor and the ceiling. In the case of air the flow pattern along the partition is laminar in the whole region, while in the case of R114 it is turbulent from the upstream end. The grade of temperature stratification of R114 is larger than that of air. The relation between the local Nusselt number and Rayleigh number is correlated as follows: Nu_x=0.35Ra_x^<0.3> for 10^5<Ra_x<1.5×10^7 (R114 and air) 0.067 Ra_x^<0.4> for 1.5×10^7≦Ra_x<8×10^9 (R114) The average Nusselt number can be correlated by the equation for a rectangular enclosure if the fluid temperatures at the 1/5 height from the upstream end and wall temperture at mid-height of partition are taken as respective representative ones. It is also demonstrated that the temperature destributions of the fluid and the partition and the heat flux across the partition can be predicted by using the present results when the temperatures of the heated and cooled walls are given.

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