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第29回宇宙環境利用シンポジウム (2015年1月24日-25日. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS)), 相模原市, 神奈川県, Space Utilization Research (January 24-25, 2015. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency(JAXA)(ISAS)), Sagamihara, Kanagawa Japan, 資料番号: SA6000035032, レポート番号: ISAS-SUR29-S27

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第28回宇宙利用シンポジウム (2012年1月23-24日. 日本学術会議), 港区, 東京都, Space Utilization Research (January 23-24, 2012. Science Council of Japan), Minato-ku, Tokyo Japan, 著者人数: 11名, 資料番号: SA6000032038, レポート番号: M38

第27回宇宙利用シンポジウム (2011年1月24日-25日, 宇宙航空研究開発機構宇宙科学研究所相模原キャンパス), 相模原市, 神奈川県, The Twenty-seventh Space Utilization Symposium (January 24-25, 2011. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS)), Sagamihara, Kanagawa Japan, Boiling heat transfer is one of promising means to be applied for the thermal management systems handling a large amount of heat in space. However, gravity effects on the two-phase flow phenomena and corresponding heat transfer characteristics have not been clarified in detail. Experiments on flow boiling heat transfer onboard "KIBO" in international space station were proposed to clarify the flow boiling heat transfer phenomena under microgravity connditions. Ground tests by using a Bread Board Model (BBM) were conducted to verify the performance of a heated test section., 著者人数: 13人, 形態: カラー図版あり, Number of authors: 13, Physical characteristics: Original contains color illustrations, 資料番号: AA0065129035

This paper presents an experimental investigation on forced convective boiling of a refrigerant HCFC123 in a mini-tube. The inner diameters of the test tubes, D are 0.51mm and 0.30mm. First, two-phase frictional pressure drops were measured in adiabatic conditions, and compared with the correlations for conventional tubes. The frictional pressure drop data were lower than the correlation for conventional tubes. However, the data were in accord with those for conventional tubes qualitatively, and correlated in the form φ_L^2/X_. Next, heat transfer coefficients were measured in conditions of constant heat flux, and compared with those for conventional tubes. The heat transfer characteristics for min-tubes were different from those for conventional tubes, and so complicated. The heat transfer coefficients for D＝0.51mm increased with heat flux, but were almost independent of mass flux. Although the heat transfer coefficients were higher than those for a conventional tube (D＝10.3mm) in low quality region, they decreased with quality. The heat transfer coefficients for D＝0.30mm were higher than those for D＝0.51mm, and almost independent of both mass flux and heat flux.

Heat generation density from semiconductor devices increases with the rapid development of electric technology. The cooling system using boiling two-phase phenomena attracts much attention because of its high heat removal potential. The technology can be applied to the cooling systems in space. Experiments on the increase of CHF (Critical Heat Flux) for flow boiling in narrow channels by improved liquid supply were conducted for the development of high-performance space cold plates. A structure of narrow heated channel between parallel plates with an unheated auxiliary channel was devised and tested by using water for different combinations of gap sizes and volumetric flow rates. Three kinds of liquid supply methods were conducted and the data were compared. CHF values of 2 x 10(exp 6) W/sq m were obtained for the improved configuration. One of liquid supply methods, where liquid is supplied to both of the main heated channel and the auxiliary unheated channel keeping the exit of the auxiliary unheated channel closed, obtains the highest CHF at total volumetric flow rate more than 1.80 l/min and for a gap size of 2 mm., 資料番号: AA0063706049

Heat transfer coefficient and pressure drop for refrigerants R-123 are measured in horizontal small tube. The stainless steel tube of 1.1mm inside diameter, 305mm heated length is used for the test section. As ranges of the main experimental parameters, heat fluxes are 0.5-33kW/m^2; mass velocities 110-3400kg/m^2s; and inlet temperatures 18-30℃. The experimental result presented that the boiling heat transfer coefficients are between 3 and 12 times as large as the single convective heat transfer coefficient. It is also presented that the two-phase frictional pressure drop could be predicted by following relation within ±20%. ΔP_F/ΔP_=1.68x^_ Where, ΔP_ is pressure drop for the total flow of fluid having the vapor properties at test section exit.

[Abstract] This paper is an experimental investigation on forced convective boiling of refrigerant HCFC 123 in a mini-tube. The inner diameters of test tubes are φ0.51 and φ0.30 mm. Ranges of the experimental parameters are as follows: the pressure P= 0.1-0.3 MPa, the mass flux G= 150-750 kg/m^2s, the heat flux q= 10-30 kW/m^2, the vapor quality x= 0.06-1.0. Heat transfer coefficients were measured in condition of constant heat fluxes, and compared with the data for a macro-scale tube. The heat transfer characteristics in mini-tubes were different from the conventional ones. The heat transfer coefficients in low quality region were higher than those for pool boiling, but decreased with vapor quality. The enhancement of heat transfer coefficients by forced convective evaporation couldn't be found. The heat transfer coefficients increased with heat flux, but were almost independent of mass flux.

過熱蒸気は単位体積当たりの熱容量が大きく、対流伝熱の他に放射伝熱、凝縮伝熱が加えられるため食品の加熱効率が高く、調理時聞を大幅に短縮することができる。そのため食品加工の分野で大きな注目を浴びている。本研究では、簡易型過熱蒸気発生器開発の基礎研究として流路内における流動沸勝の熱伝達について実験を行った。