增强型太阳池提热稳定性与热盐双扩散机理研究

The thermal process water desalination technology driven by solar pool, is a kind of solar desalination technology with a broad prospect. In this project, a kind of enhanced solar pond is employed as the heat source of low temperature multiple effect desalination, and the operation mechanism of the enhanced solar pond is put forward by methods of experiment testing, theoretical analysis and numerical simulation. The energy efficiency of each layer in the solar pond are confirmed by the analysis of heat balance under the condition of heat extraction. The thermal stability of mathematics model of the enhanced solar pond has been established, which is under complicated conditions of porous media, auxiliary solar heat and heat extraction.The turbulence model of heat-salt double diffusion with large eddy simulation in the enhanced solar pond is established to form the systematic new knowledge of solar pond on the molecular diffusion effect and turbulent diffusion effect. Base on the heat extraction experiment in an enhanced solar pool, the temperature characteristic of enhanced pool with heat extraction is revealed, besides the theory and simulation results of the objective are validated.The heat and mass transfer mechanism the enhanced solar pond are further studied,which will provide theoretical basis and scientific guidance for research and application of of solar pond in the field of multi-effect evaporation desalination.

以太阳池为热源的热法海水淡化技术，是一种具有广阔前景的太阳能海水淡化技术。本项目提出将一种增强型太阳池作为低温多效海水淡化的热源，通过实验测试、理论分析和数值模拟三大手段，深入研究增强型太阳池的运行机理。通过热平衡理论分析，确定提热状况下太阳池各层的能源效率；建立增强型太阳池在存在多孔介质、太阳能辅助集热、提热等复杂工况下的提热稳定性数学模型，形成比较系统的提热稳定性基本理论；通过构建增强型太阳池热盐双扩散大涡模拟湍流模型，形成比较系统的太阳池分子扩散效应和湍流扩散效应的新知识；通过增强型太阳池提热实验装置的搭建与运行，揭示增强型太阳池提热下的温度特性，验证本项目的理论与模拟成果。深入探索提热工况下增强型太阳池的传热传质机理，为太阳池在多效蒸发海水淡化领域的应用提供强有力的理论和技术支撑。

本项目通过数值模拟、理论分析和实验测试三大手段，深入研究增强型太阳池的运行机理。建立了太阳池热盐双扩散模型与稳定性模型，对梯形太阳池进行二维非稳态数值模拟研究，在模型有效性验证基础上，分析了太阳池温度变化、速度与涡量分布、分界面盐浓度变化规律及稳定性等特性；采用大涡模拟湍流模型研究太阳池内的微湍流特性，同时建立了多孔介质模型，集热器模型与加盖模型，讨论了各强化措施对太阳池温度特性的影响。.基于太阳池热平衡理论，建立太阳池能源效率与火用效率表达式，对梯形太阳池的能源效率与火用效率进行分析，计算了加膜太阳池和加集热器太阳池的能源效率，并通过算例进行了以太阳池为热源的海产品越冬养殖的经济性分析。以多孔介质太阳池为背景，建立了多孔介质随机结构模型，采用大涡模拟方法分析了多孔介质孔隙内的速度场、涡量场演变历程，通过数值模拟研究了多孔介质内的湍流特性与传热特性。在实验方面，对多种多孔介质材料的蓄热降浊特性进行了室内试验研究，在室外建立了小型太阳池实验系统，采用向池底填充多孔介质、加透明薄膜以及引入太阳能集热器方法强化太阳池热性能，讨论了各强化措施对太阳能热性能的影响。基于增强型太阳池的基本理念，提出了一种潮汐驱动的集热蓄热式暖棚太阳池的蓄水方法方法。