Geological carbon dioxide (CO₂) sequestration (GCS) in deep saline aquifers is a promising solution to mitigate the impact of anthropogenic CO₂ emissions on global climate change. CO₂ dissolved in formation water increases the solution density and can lead to miscible density-driven downward convection, which significantly accelerates the dissolution trapping of injected CO₂. Experimental studies on miscible density-driven convection have been limited. In the laboratory, we found an empirical linear correlation between reflected green light intensity and solute concentration, which enabled in situ measurements of solute concentrations in the spatial and temporal domains and consequently the mass flux across the top boundary of the porous medium. Using the novel experimental techniques, we determined the critical Rayleigh-Darcy number and critical time scales for the onset of density-driven instability and convective dissolution. This is the first study to determine these critical system parameters using laboratory experiments.

中文翻译：

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多孔介质中密度驱动不稳定性和对流溶解的新实验研究

深部咸水层中的地质二氧化碳 (CO ₂ ) 封存 (GCS) 是减轻人为 CO ₂排放对全球气候变化影响的有希望的解决方案。溶解在地层水中的CO ₂增加了溶液密度，并可能导致混相密度驱动的向下对流，这显着加速了注入的 CO ₂的溶解捕集。对混相密度驱动对流的实验研究受到限制。在实验室中，我们发现反射的绿光强度和溶质浓度之间存在经验线性相关性，这使得原位测量空间和时间域中的溶质浓度，从而测量穿过多孔介质顶部边界的质量通量。使用新的实验技术，我们确定了密度驱动的不稳定性和对流溶解开始的临界瑞利-达西数和临界时间尺度。这是使用实验室实验确定这些关键系统参数的第一项研究。