NANO/MICRO SCALE DRYING MODEL BASED ON LIQUID-VAPOR PHASE CHANGE THEORY AND DEVELOPMENT OF NEW DRYING METHOD

基于液-汽相变理论的纳微米干燥模型及新型干燥方法的开发

• 批准号: 17360099
• 负责人: TSURUTA Takaharu
• 金额: $ 10.32万
• 依托单位: Kyushu Institute of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2005
• 资助国家: 日本
• 起止时间: 2005 至 2007
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17360099/
• 关键词: DRYING; NANO; MICRO SCALE; MOLECULAR DYNAMICS; MICROWAVE VACUUM DRYING; POROUS MEDIA; PHASE CHANGE; THERMAL ENGINEERING; FLUID DYNAMICS; 三相界面; 濡れ性; 凝縮係数

We present a novel drying method by using microwave. Microwave is irradiated in pulse or intermittently so as to keep the temperature of material at around room temperature in a reduced pressure system. Energy of microwave is supplied just for the latent heat for evaporation. Also, by introducing a small amount of external air into the system, water vapor can be effectively carried out of the drying system. The drying time was successfully shortened as compared with the warm-air drying and the drying at room-temperature results in good quality for dried materials. We also examined the internal resistance for water transport based on the porous media model. It is found that the internal channel for the water transportation can be kept during the microwave-vacuum drying and it results in the high permeability at the wide range of moisture content. In this study, molecular dynamics simulations have also been carried out to study the effect of the nanostructures on the wetting characteristics at the solid-liquid interface. The wettability of the solid-liquid interface is examined with evaluating the contact angles at the three-phase interface. A modified description of contact angle in consideration of molecules filling ratio among nanostructures was proposed. The simulations show that the evaporation rate of the ultra thin liquid film decreases when the film thickness is thinner than 4〜6 molecular layers. We have done the dropwise condensation tests to obtain reliable experimental data on the condensation coefficient of water. A high vacuum system was developed to eliminate the effect of non-condensable gases on liquid-vapor interface mass transfer. Also, a thin film thermometer made of copper and nickel was formed onto the surface of silicon wafer for a direct measurement of surface temperature. We got the values in the range of 0.5-0.6.

提出了一种新的微波干燥方法。微波是在减压系统中以脉冲或间歇方式照射，以使物料的温度保持在室温左右。微波的能量仅为蒸发潜热提供。此外，通过将少量的外部空气引入系统中，可以有效地将水蒸气带出干燥系统。与热风干燥相比，干燥时间大大缩短，干燥后的物料质量良好。我们还研究了基于多孔介质模型的水传输的内部阻力。结果表明，微波真空干燥过程中保持了内部水分传输通道，在较宽的含水率范围内保持了较高的透气性。在这项研究中，分子动力学模拟也进行了研究的纳米结构上的润湿特性在固液界面的效果。通过测定三相界面的接触角，考察了固液界面的润湿性。提出了一种考虑纳米结构间分子填充比的接触角描述方法。模拟结果表明，当膜厚小于4 × 6分子层时，超薄液膜的蒸发速率降低。为了获得水的冷凝系数的可靠实验数据，我们进行了滴状冷凝实验。为了消除不凝性气体对气液界面传质的影响，研制了一套高真空系统。此外，在硅晶片表面上形成由铜和镍制成的薄膜温度计，用于直接测量表面温度。我们得到的值在0.5-0.6之间。

项目成果

Evaluation of Internal Transport Resistance of Seafood in Warm-air Drying Process

海鲜暖风干燥过程中内部输送阻力的评价

• 发表时间: 2005
• 作者: Tadahisa;Hayashi;Takaharu;Tsuruta
• 通讯作者: Tsuruta

Internal resistance to water mobility in seafood during warm air drying and microwave-vacuum drying

• DOI: 10.1080/07373930701439152
• 发表时间: 2007-01-01
• 期刊: DRYING TECHNOLOGY
• 影响因子: 3.3
• 作者: Tsuruta, Takaharu;Hayashi, Tadahisa
• 通讯作者: Hayashi, Tadahisa

間欠照射と外気導入によるマイクロ波減圧乾燥の乾燥促進

通过间歇照射和引入外部空气加速微波真空干燥的干燥

• 发表时间: 2006
• 期刊: 日本機械学会論文集B編 72
• 作者: Gyoko Nagayama;Atsushi Tokunaga and Takaharu Tsuruta;Takaharu Tsuruta and Tadahisa Hayashi;長山 暁子;鶴田 隆治
• 通讯作者: 鶴田 隆治

Evaporation Characteristics of an Ultra Thin Liquid Film on a Solid Surface

固体表面超薄液膜的蒸发特性

• 发表时间: 2005
• 作者: Mitsuaki;Matsuo;Takaharu;Tsuruta;Gyoko;Nagayama
• 通讯作者: Nagayama

On the evaporation rate of ultra-thin liquid film at the nanostructured surface: A molecular dynamics study

• DOI: 10.1016/j.ijthermalsci.2009.06.001
• 发表时间: 2010-01-01
• 期刊: INTERNATIONAL JOURNAL OF THERMAL SCIENCES
• 影响因子: 4.5
• 作者: Nagayama, Gyoko;Kawagoe, Masako;Tsuruta, Takaharu
• 通讯作者: Tsuruta, Takaharu