A New Approach Toward Low-Temperature Thermal Engineering Without Fluorocarbon Refrigerants

1.微通道内两相流的传热和流动特性(K.Hijikata)：对微通道内的两相流动进行了实验研究，以确定其流动和换热特性。高度为209微米的25个平行微通道的阵列。在不锈钢板上制造出宽度为212微米，长度为9.96毫米的不锈钢。结果表明，微通道内两相流的摩擦因数小于常规尺寸通道内的摩阻系数，两相内的努塞尔数比纯液体的努塞尔数大一倍。2.吸收式制冷机中的高性能换热(H.Inaba)：对填充在圆柱形吸收层中的高性能有机纤维吸收剂在不同密度下的吸附/解吸特性进行了实验研究。结果表明，吸附/脱附…与常规无机纤维吸收剂相比，本研究制备的吸收剂具有更好的吸附性能。3.多组分介质的强化换热与控制(A.Takimoto)：对膜状/液滴联合冷凝的微尺度特性和冷凝换热特性进行了分析和实验研究。试验采用无机制冷剂和有机材料的混合物作为二元不混相液。本分析模型的预测结果与实验结果吻合较好。4.新型制冷剂热物性的测试。用瞬变热线法测量了HFC-32和HFC-125混合物的液体导热系数，温度范围为213K-293K，压力范围为2-30兆帕，HFC-32质量分数为0.249，0.5，0.75，精密度为0.5%。测定了HFC-32和HFC125的固体导热系数。5.利用电场控制霜冻的生长。为了促进结霜和抑制结霜，对电场对结霜现象的影响进行了实验研究。阐明了电压、脉冲宽度、频率对除霜效果的影响，并对除霜机理及表面润湿性的影响进行了探讨。6.结霜和除霜换热器的运行特性(青木K.Aoki)：对结霜/除霜循环换热器的换热特性和性能进行了研究。此外，还从实验上阐明了超大接触角表面对结霜生长的影响。7.泥浆层熔化和流动特性的实验研究(S.Fukusako)：一个经验较少的实验

1. Heat transfer and flow characteristics of two-phase flow in the microchannels (by K.Hijikata) : An experimental study on two-phase flow in microchannels has been conducted to identify the characteristics of flow and heat transfer. An array of 25 parallel michrochannels with the dimensions of 209 mum in height. 212 mum in width, and 9.96 mm in length for each one was manufactured on the stainless steel plate. The results showed that the friction factor for two-phase flow in the microchannels was smaller than that in conventional sized channels, and that the Nusselt number in the two-phase reached twice as large as that for liquid only. 2. High performance heat transfer in the absorption type refrigerator (by H.Inaba) : An experimental investigation on the adsorption/desorption characteristics of high performance organic fibrous absorbent, which was filled in the cylindrical absorption layr under a variety of densities, has been carried out. The results showed that the adsorption/deso … More rption characteristics of the absorbent in the present study is much better than that of conventional inorganic fibrous absorbent quantitatively. 3. Enhancement and Control of Heat Transfer by using a Multicomponent Medium (by A.Takimoto) : An analytical and experimental investigation on the micro-scale characteristics and the condensation heat transfer characteristics in the filmwise/droplet combined condensation has been carried out. A mixture of inorganic refrigerant and organic materials was adopted as the binary immiscibel liquid under the test. The predictions obtained in the present analytical model agree well with the experimental results. 4. Measurement of the Thermophysical Properties of the New Refrigerants. (by Y.Nagasaka) : The Liquid thermal cnductivity of the mixtures of HFC-32 and HFC-125 has been measured in the trmperature range 213K-293K and in the pressure range 2-30 Mpa with the HFC-32 mass fractions of 0.249,0.5,0.75 by using the transient hot-wire method with the precision of 0.5%. The solid thermal conductivity of HFC-32 and HFC125 has been also measured. 5. Control against the Growth of Frost by Utilizing the Electric Fields. (by M.Kumada) : In order to promote the defrosting and to control sagainst the frost growth, the effect of electric field on frosting phenomenon has been investigated experimentally. The effect of voltage, width of the pulse, and frequency on the defrosting was clarified, furthermore, the defrosting mechanism and the effect of the wettability of the surface was discussed. 6. Characteristics of Heat Exchanger Operating with Frosting and Defrosting (by K.Aoki) : The heat transfer characteristics and the performance of the heat exchanger with frosting/defrosting cycle have been investigated. Furthermore, the effect of the surface with ultra-high contact angle on the growth of the frost has been clarified experimentally. 7. Experimental study on the melting and flow characteristics of slush layr (by S.Fukusako) : An experim Less