| 摘要: |
| 湖泊、水库等内陆水域近年来被认为是碳排放热区，其中发生在水-气界面的二氧化碳（CO2）、甲烷（CH4）等温室气体扩散释放是湖泊与水库碳排放的最重要途径。扩散释放是气体在气-液两相间的传质过程，气液传质系数是计算温室气体扩散释放通量的关键参数，而风速通常被认为是决定湖泊、水库表层水体气液传质系数取值的主要因子，然而目前对于风速对温室气体气液传质系数影响的研究大多基于示踪气体野外观测结果，还尚缺乏考虑温室气体气液传质特性的机理试验研究，给定量评估水域温室气体扩散释放量及源汇变化造成不确定性。通过机理试验分别探究不同水面风速影响下的水体CO2与CH4的浓度变化与在水-气界面的释放规律，试验结果表明CO2与CH4的气液传质系数与风速呈正相关关系，分析认为风速的增大可促进水面湍动，且风生成的水面波增大了气液接触面积，从而促进气液传质发生。同一工况下的CO2与CH4气液传质系数的对比结果表明，除分子扩散系数外，气体溶解度等气体其他的物理、化学和生物性质也会对气液传质产生影响，且随着风速的增大，气体传质特性的影响更为显著。基于试验结果建立了考虑温室气体在不同风速影响下的气体传质特性的气液传质系数取值公式，并应用该公式与传统经验公式进行通量计算差异比较分析，分析发现传统经验公式的通量计算结果更高，但不同公式结果仍然具有较好的一致性趋势。研究结果将加深对不同温室气体气液传质机理与传质特性差异的理解，有助于科学分析湖泊、水库等水域温室气体扩散释放的影响机制，进一步提高碳排放评估的准确性。 |
| 关键词: 二氧化碳 甲烷 水面湍动 浓度变化 气体性质 |
| DOI： |
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| 基金项目:国家重点研发计划项目（2022YFC3203504）；国家自然科学基金项目（52209101；U2340222） |
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| Experimental study on the effect of wind speed on the gas-liquid mass transfer coefficient of greenhouse gases |
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XUAO1, LIZHE, HUANGJUPING2, MAHONGHAI
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1.Chongqing Jiaotong University;2.Chongqing Institute of Green and Intelligence Technology, Chinese Academy of Sciences
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| Abstract: |
| In recent years, inland water bodies such as lakes and reservoirs have been recognized as hotspots for carbon emissions, with the diffusion and release of greenhouse gases like carbon dioxide (CO2) and methane (CH4) at the water-air interface being the most significant pathways for carbon emissions from these water bodies. Diffusion release refers to the mass transfer process of gases between gas and liquid phases, where the gas-liquid mass transfer coefficient is a key parameter for calculating the flux of greenhouse gas diffusion. Wind speed is generally considered the primary factor affecting the gas-liquid mass transfer coefficient in the surface waters of lakes and reservoirs. However, most current research on the impact of wind speed on the gas-liquid mass transfer coefficient of greenhouse gases is based on field observations of tracer gases, lacking mechanistic experimental studies that consider the characteristics of gas-liquid mass transfer. This results in uncertainties when quantitatively assessin |
| Key words: Carbon dioxide Methane Surface turbulence Concentration variations Gas properties |
