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混合蒸気の濃度差マランゴニ凝縮における赤外レーザー吸光法による凝縮液厚さ測定

利用红外激光吸收法测量马兰戈尼凝结中由于混合蒸汽浓度差而产生的凝结水厚度

基本信息

批准号：
12650194
负责人：
宇高義郎
金额：
$ 2.3万
依托单位：
Yokohama National University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

项目摘要

"Positive system"と呼ばれる低沸点成分に比べて高沸点成分液の表面張力の大きい混合蒸気系の凝縮過程において、濃度差表面張力不安定によって、表面の温度分布に起因する濃度・表面張力分布が生じ,擬似的な滴状凝縮などの凝縮液形態が出現する。凝縮液抵抗は低減し、伝熱性能の飛躍的な向上が見られる条件が比較的広範に現れる。本研究は、濃度差マランゴニ凝縮現象の熱伝達機構・特性を解明するため、波長3.39μm赤外レーザー光の吸収特性を用いる新たな方法により、本現象における凝縮液膜厚の変化特性の精密測定を行うことを目的として、以下の結果を得た.(1)水-エタノール混合液体の消光性質を明らかにした.(2)レーザ光の集光により,微小な薄液膜部寸法に対応する直径約30μmのレーザ光照射寸法を実現した.(3)液膜厚さ測定位置と凝縮液挙動の対応関係を明確にした.(4)本測定の液膜厚さ1μm程度の測定へ適用可能であることを示した.さらに、(5)液膜厚さと凝縮液挙動の同時観測により,離脱液滴による掃除後の薄液膜および液滴間薄液膜の厚さ変化の測定を行った.(6)低過冷度領域から初生液滴間隔の減少に伴い最小液膜厚さは減少する傾向を示し,さらに冷却強度を増大させると,初生液瀧間隔および最小液膜厚さとも増大した.(7)最小液膜厚さは濃度の減少に伴って減少し,本測定の範囲においては約1μmであった.(8)本研究と既報の結果から,極大熱伝達率付近の過冷度域で,初生液滴間隔,離脱液滴直径,最小液膜厚さとも最小となることなど,凝縮特性曲線における熱伝達率変化特性とそれらの特性量変化の間には類似の対応関係が存在していた.(9)上記(8)から,熱伝達率のピーク付近で駆動力は最も強まると推測され,凝縮液膜は薄膜化し,その結果としての凝縮液熱抵抗の減少が熱伝達率向上の主要因の一つとなっていることが結論される.

"Positive system" the low boiling point composition is higher than that of the high boiling point liquid. The mixed evaporation system is the process of condensation, the degree of difference, the instability of the surface force, the temperature distribution of the surface, the surface force distribution, the temperature distribution, the surface force distribution, the temperature distribution, the temperature distribution, the surface force distribution, the temperature distribution, the surface force distribution, the temperature distribution, the temperature distribution, the surface force distribution, the surface force distribution, the temperature distribution, the temperature distribution, the surface force distribution, the temperature distribution, the surface force distribution, the temperature distribution, the surface force distribution, the The condensate is resistant to the low temperature, the upward pressure of the performance and the performance of the condensate. In this study, the optical absorption characteristics of the optical absorption of infrared light at the wavelength of 3.39 μ m are explained in this study, and the optical absorption characteristics of the optical absorption of infrared light at the wavelength of 3.39 μ m are studied by using the new method of optical absorption in this study. the accurate determination of the characteristics of the thickness of liquid film, The following results show good results. (1) the extinction property of the mixture of water and water is very good. (2) the light is collected by the light collector. The diameter of the micro-thin liquid film is about 30 μ m. (3) the position of the liquid film thickness is determined. (4) the liquid film thickness of 1 μ m is measured by the method of measuring the thickness of the liquid film. The thickness of the liquid film, (5) the thickness of the liquid film, the temperature of the condensate, the temperature of the liquid, the thickness of the liquid film, the thickness of the liquid film. (6) in the field of low undercooling The minimum liquid film thickness of the primary liquid is much higher than that of the primary liquid. (7) the temperature of the minimum liquid film thickness is smaller than that of the minimum liquid film thickness, and the range of this measurement is about 1 μ m. (8) the results of this study show that the extremely high temperature is close to the temperature range of the temperature range, the separation between the primary droplets, the diameter of the liquid droplets, and the minimum thickness of the liquid film. The characteristic curve is similar to that of the liquid film. (9) in the (8) section above, the liquid film is thinned and the liquid film is thinned. The results showed that the increase in the rate of low concentration of anticoagulant was mainly due to the increase in the rate of low temperature.