非稳态热场环境下的深海热液温差能捕获与利用机理研究

Deep-sea hydrothermal energy is regarded as an important renewable energy. The hydrothermal power generation is expected to be an alternative power source for deep-sea hydrothermal observation, seabed resources exploration and mining in future. However, the thermal energy harvesting and sustainable power generation from deep-sea hydrothermal fluids faces great challenges due to the variability of hydrothermal venting and the high load of sulfide particles in the fluids. The proposed project is focused on the research of the energy harvesting and utilization mechanism of deep-sea hydrothermal fluid in unsteady thermal field environment. First, the fluid-solid-thermal coupling model of the energy harvesting device-hydrothermal fluid- particle will be established by applying the buoyancy jet theory and the discrete element method, to reveal the heat transfer process of the hydrothermal energy conversion. The movement behavior of the sulfide particles inside the hydrothermal energy harvesting device will be studied by using the experimental simulation and high speed video observation. It is supposed to illuminate the removal mechanism of the particles adhered on surface of the heat exchanger by the regulation of the inner flow field and the outside interference, and then to realize the efficient harvest of the hydrothermal energy. The energy regulation model will be built based on the energy balance among the power generation module, energy storage module and the loads. Then the self-adaptive power management strategy will be put forward so as to improve the efficiency of the hydrothermal power generation and the level of comprehensive utilization of the energy. This study will lay a solid foundation for sustainable power generation from deep-sea hydrothermal fluids.

深海热液所蕴含的巨大热能是一种重要的深海可再生能源，热液温差发电可作为深海热液观测、深海资源勘探与开发的重要电能供给方式。热液活动的多变性及热液流体中的高浓度颗粒物给热液温差能捕获和长期稳定发电带来严重影响，据此本项目提出开展非稳态热场环境下的热液温差能捕获与利用机理研究。运用浮力射流理论与离散元相结合的方法，构建发电器与热液羽流及颗粒物的流-固-热耦合模型，以更清晰地揭示热液温差发电的传热过程。采用实验模拟和高速摄像观察来研究颗粒在发电器内的产生、粘附和脱落行为，阐明内部流场调制及外部干预对粘附颗粒的去除机制，从而实现热液温差能的高效捕获。通过分析确立发电单元、储能单元与负载单元之间的能量平衡关系，建立温差发电系统的能量调控模型，提出自适应电能管理控制策略，以有效提高温差发电效率和电能的综合利用水平，为可持续大功率深海热液温差发电奠定基础。

本项目针对非稳态热场下的热液温差能捕获与发电机理开展应用基础研究，主要对热液环境下温差发电器强化传热、基于流场调制的温差能高效捕获机理、热液温差发电电能管理及功率匹配控制、热液温差发电器样机研制与实验四个方面展开研究。已按照研究计划完成了全部研究内容，主要成果如下：.（1）在热液温差发电强化传热研究方面，通过建立热液喷口羽流起始段的速度场和温度场模型，在温差发电器流道内加入扰流元件实现热端的强化传热；提出了基于喷射引流的发电器冷端冷却方法，开发了一体化喷射引流冷却结构，将发电器冷端传热从自然对流转变为强制对流，实现冷端高效散热。.（2）在基于流场调制的温差能高效捕获机理研究方面，构建了热液与温差发电器相互作用的多物理场模型，该模型实现了压力、传热、流动及发电等多物理场的耦合。建立了硫化物颗粒在壁面处的碰撞黏附模型，为进一步探究颗粒物去除方法和效果，提高温差发电器工作效率和使用寿命打下基础。.（3）在热液温差发电电能管理及功率匹配控制研究方面，提出了一种基于电压阈值的电能管理控制策略，建立了热液发电系统的输出功率模型。搭建了实验室环境下的电能管理实验平台，验证了电能管理系统各个模块以及总体的功能。.（4）在热液温差发电器样机研制与实验方面，设计并研制了一体填充式与钛箔密封式两种深海耐压型热液温差发电器样机，利用导热油循环加热系统对两种发电器进行了发电性能测试。一体填充式温差发电器在冷热端温差为68℃左右时，输出功率达到9.57~9.77W，钛箔密封式温差发电器最大输出功率达到22W。.