注記 |
In the previous report — Part 1, Chapter IV — it was clearly shown through experiments that the air dissolved in the percolating water, was released as bubbles in free gas into the pores of porous medium, and that as the result, the percolating flow was changed from saturated into unsaturated. In this present report — Part 2 —, of the changing flow with the course of time in the pores being unsaturationized and of its permeability being then degraded, a quantitative analysis was made. As the principal cause of air-bubbles released in the pores in porous medium, it can be considered that the air solubility in liquid varies. Generally, the air solubility in liquid (Ω) varies according to the changing pressure (P) and temperature (T), as Ω = Ω(P, T) In chapter V, at the constant temperature (T), and under the difference between initial pressure (P_0) of the supplied water and the optional pressure (P) in porous medium, both experiments and analysis were made. The method of analysis: as the principle of the air-bubbles released in the pores in porous medium, Henry's Law concerning the air solubility based on the difference of pressure between the initial in supplied water and that in porous medium, could be presumed to form. According to the Law applied in porous medium, therefore, the quantitative analysis of unsaturated liquid intrinsic permeability, as well as the degree of liquid saturation, was made. The method of experiment: In order to simplify the analysis of percolation, porous medium was set up in siphon tube under the constant pressure produced in the medium. As the degree of liquid saturation (S_w) is the function of the time, both unsaturated liquid intrinsic permeability K(S_w) and liquid relative specific permeability (X), also turn to be respectively the function of time. The theory was well satisfied with the experiment. In chapter VI, the former experiment and analysis as described in chapter V, were further developed: at the changing temperature (T) also, the unsaturationizing in porous medium was considered. Here, more generalized quantitative analysis of the degree of liquid saturation (S_w) and of the unsaturated liquid intrinsic permeability K(S_w), was made. In this case, the critical temperature varied according to the changing pressure. Above the critical temperature, the unsaturationizing went on in the pores: the theory was well satisfied with the experiment. Below that, however, air-bubbles in the pores were absorbed and dissolved again: a discrepancy between theory and experiment appeared, here. The probability of air-bubbles being made contact with water, as well as the air-solubility of percolating water, came into be problem, upon which a cause of hysteresis in the unsaturated liquid intrinsic permeability, could considered to be based. In this Part 2, the pressure (P) stands for the absolute pressure, the pressure head (H) for the absolute head; whereas, (p) for the pressure under the standard atmospheric pressure, and (h) for the pressure head under the same.
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負圧浸透においては,(1)浸透層内に負圧は発生しているが,飽和浸透が維持される場合,(2)時間の経過とともに,飽和浸透流から,不飽和浸透流へと移行する場合,の二つの性質の異なつた流れが存在する.この研究では,浸透液体に溶解されている気体により,流れが飽和浸透流から不飽和浸透流に移行する過程を明らかにし,浸透層間ゲキの飽和度の変化,および不飽和浸透性の変化に関する定量化を試みた.この論文は,第1部および第2部の二つの部から構成されている.第1部は,第I,II,IIIおよびIV章の四つの章を含んでおり,第2部は,第V,VIおよびVIII章の三つの章を含んでいる.第I章では,この研究を行なうに至つた端緒について述べている.第II章では,Darcy法則の微分方程式表示および,浸透流の基礎方程式に関して,既往の研究を中心に検討考察を行なつた.第III章では,成層鉛直降下浸透において,浸透層内に負圧は発生するが,飽和浸透が維持される場合の流れについて,実験的・理論的な解析を行なつた.一般にこのような負圧浸透においては,ポテンシアル・コウ配が大きいけれども,Darcy法則がまだ有効であり正圧,負圧に関係なく飽和浸透流としての取り扱いが可能なことを明らかにした.第IV章では,成層鉛直降下浸透および傾斜成層浸透に関する実験を行なつた.負圧浸透において,時間の経過による浸透層間ゲキ内の不飽和化の過程と,それにともなう圧力分布の変化について実験的な解析を行ない,その特性に関する知見を得た.また,層内間ゲキでの浸透液体からの溶解気体の放出が,間ゲキの不飽和化の原因であるとの結論に至つた.第V章では,浸透液体に温度変化が存在せず,圧力変化のみが存在する負圧浸透流について,浸透層間ゲキ飽和度の変化,および不飽和浸透性の変化について理論的な定量化を試みた.実験はサイフォン内で行なつている.理論と実験とはよく一致している.第VI章では,さらに一般化して,浸透液体に温度変化,圧力変化がともに存在する場合についての定量化を試みた.この場合には,任意の圧力変化に対応して限界温度が存在する.限界温度以上では,間ゲキ内の不飽和化が進行する.理論と実験とは,よく合致している.限界温度以下では,間ゲキ内の空気泡の吸収,再溶解を生ずる.この場合には,理論と実験との間に時間的なズレを生ずる.このことに対する考察を行なつた.この研究における実験は,浸透液体としては水を用い,浸透層の構成粒子としては砂粒子およびガラス球を用いて行なつたものである.
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