漂浮式多孔介质高效吸收太阳能产蒸汽传热传质机理研究

Solar steam generation has been widely used in thermal power generation, seawater desalination and phase separation system etc. Recently, solar steam generation via floating porous solar absorber attracts numerous attentions due to its excellent steam generation performance. The key factors to improve the solar steam generation efficiency are the heat transfer control and water/vapor diffusion limitation restrict in porous media. Therefore, it is urgently need to investigate the mechanism of multiphase flow and heat and mass transfer in this field. According to the solar absorption, photothermal conversion, heat transfer and mass diffusion in this technology, this project proposes to carry out experimental and numerical study on these problems. As important media to collect the solar energy, broadband absorption nanoparticles are designed and synthesized. Furthermore, the full-spectrum and multi-angle absorption porous media are prepared with nanoparticles. Highly efficient solar steam generation would be realized with floating full-spectrum and multi-angle absorption porous media. In addition, Finite Difference Time Domain and Finite Element Analysis methods are applied to build subwavelength scale solar responses and photothermal conversion model, which is used to obtain the mechanism of heat transfer and the coupling of electromagnetic field and thermal field at micro/nano scale. Monte Carlo Ray Tracing method and Computational Fluid Dynamics method are applied to unify the photothermal conversion, heat transfer and mass transfer in one simulation and reveal the mechanism on coupling of photothermal conversion, heat transfer and mass transfer in solar-driven steam generation with the porous media. This project provides theoretical basis for the optimizing and developing of solar steam generation via floating porous solar absorber.

太阳能产蒸汽在热发电、海水淡化和相分离系统等领域中都有着重要应用，近年来漂浮式多孔介质高效吸收太阳能产蒸汽技术由于其良好的产蒸汽性能受到了研究者的广泛关注。解决多孔介质内的热量输运控制和水/蒸汽扩散局限性等问题是提高产蒸汽效率的关键所在，针对此问题，亟需开展相关过程中的多相流动传热传质机理研究。本项目针对漂浮式多孔介质吸收太阳能产蒸汽技术中的光热转换、热能输运和多相流动传质等热物理过程，开展实验和数值模拟研究，制备宽光谱吸收性纳米颗粒，开发全光谱多角度太阳能吸收性多孔介质，实现高效的太阳能产蒸汽；基于时域有限差分和有限元分析方法，构建微纳尺度光谱响应和光热转换模型，获得微尺度热能输运规律和电磁场-温度场耦合机制；通过蒙特卡罗光线追踪法、计算流体力学等方法，建立多孔介质结构中光热转换-传热-传质耦合分析模型，揭示其中光热-传热-传质多场作用机制，为该技术的优化设计和推广应用提供理论基础。

本项目围绕漂浮式多孔介质吸收太阳能光热产蒸汽特性开展了实验和数值模拟研究，分别开展了高效太阳能吸收及光热转换特性研究和多孔介质光热驱动水蒸发相变传热传质机理研究。通过Hummers方法制备了石墨烯纳米颗粒，进行了石墨烯纳米材料的表征，石墨烯-滤纸复合多孔膜的制备与表征，石墨烯多孔泡沫的制备与表征，石墨烯基多孔介质的亲疏水性研究和石墨烯基多孔介质的光热响应研究。进一步完成了石墨烯基多孔介质太阳能光热利用研究，包括石墨烯多孔介质吸收太阳能光热产蒸汽和强化油污处理，获得了多孔介质吸收太阳能产蒸汽的相关规律。建立了多孔介质中多相输运模型，完成了多孔介质中的渗流模拟和液滴输运模拟，揭示了多孔介质中的多相输运特性。本项目研究发展了漂浮式多孔介质吸收太阳能产蒸汽海水淡化技术，为光热多孔介质在太阳能光热利用领域的应用奠定了理论基础。