Abstract This study presents a method for the experimental determination of local volumetric mass transfer coefficients k L a L in a high-pressure two-phase flow of water (H2O) and carbon dioxide (CO2) in a micro-capillary using Raman spectroscopy. H2O and CO2 are continuously and co-currently fed at high pressure (8, 9 and 10 MPa) and moderate temperature (303 K) into a fused silica micro-capillary. A segmented two-phase flow is obtained therein and the fraction of CO2 in the water-rich phase is measured in-situ at different points along the capillary using Raman spectroscopy. A modified Henry’s law is used to compute the equilibrium compositions of the water-rich phase at the desired pressure and temperature. A mixture density model is used to convert the fraction of CO2 in the water-rich phase into a CO2 concentration. The volumetric liquid mass transfer coefficient is computed at various axial locations along the capillary, from the contacting zone to the end of the capillary. Experimentally derived k L a L values range between 2.10−3 and 5.10−3 s−1.

中文翻译：

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使用拉曼光谱测定毛细管中高压两相流的传质系数

摘要 本研究提出了一种使用拉曼光谱实验测定微毛细管中水 (H2O) 和二氧化碳 (CO2) 高压两相流中局部体积传质系数 k L a L 的方法。H2O 和 CO2 在高压（8、9 和 10 MPa）和中等温度 (303 K) 下连续并流进入熔融石英微毛细管。在其中获得分段的两相流，并使用拉曼光谱在沿毛细管的不同点原位测量富水相中的 CO2 分数。修改后的亨利定律用于计算在所需压力和温度下富水相的平衡组成。混合物密度模型用于将富水相中的 CO2 分数转换为 CO2 浓度。体积液体传质系数是在沿毛细管的不同轴向位置计算的，从接触区到毛细管末端。实验得出的 k L a L 值范围在 2.10-3 和 5.10-3 s-1 之间。