Massively parallel computational methods for combined-modes heat transfer with applications to concentrated solar power technologies

背景：拟议的研究计划是在高效能源系统领域：特别是通过热-机械转换的太阳能发电。之所以对该计划感兴趣，是因为这样一个事实，即尽管大多数情况下需要这种技术，但目前平均每年的转换效率仅为15%-18%。这样生产的电力成本可能是使用传统化石燃料发电的三倍之多。 当转换效率显著提高时，太阳能热电厂的竞争力将会取得突破，如果这种改进的技术仍然简单、可靠和廉价的话。 所希望的突破可能存在于高温(1000℃或以上)联合循环发电厂，燃气轮机和蒸汽轮机串联运行，其转换效率可达60%，整体效率可达30%。在这样的温度下提供太阳能将涉及重大挑战，例如：设计高温材料，优化接收器和光学装置中的辐射和对流换热，以及用于高浓度的光学装置。 目标：本研究计划的主要目标是： 1)研究了聚光太阳能在多孔材料上体积吸收的基本原理，更具体地说，研究了高压气流作用下半透明网状陶瓷材料的体积吸收原理。 2)用计算手段同时研究“数值”或虚拟网状多孔陶瓷； 3)建立、实施和验证了多孔介质中渗流数值模拟的方法； 4)建立、实施和验证了多孔介质中复合换热的数值方法，并在此基础上进行了数值模拟。 5)将两种方法结合起来，对上述虚拟陶瓷进行了研究，并在此基础上提出了一种基于虚拟陶瓷的虚拟陶瓷研究方法。 6)对按优化设计构造的真实陶瓷的转化性能进行了实验测试； 7)基于格子Boltzmann方法重新编写了部分主要代码，这在理论上需要提高计算时间。 结果：本研究的结果将有助于正确理解光热转换单元(体积吸光器)在全球技术中的关键。 我国与世界其他国家一样，将在未来几十年面临能源危机；在这方面，热能工程的研究可能会导致加拿大开发新的至关重要的能源和环境技术。

CONTEXT: The proposed research program is in the field of high-efficiency energy systems: in particular, solar-electricity production by thermo-mechanical conversion. The interest in the program is motivated by the fact that such technology, although mostly required, is currently limited to an average annual conversion efficiency of 15-18%. The cost of electricity thusly produced may be as much as three times that of electricity produced using conventional fossil fuels. A breakthrough in the competitiveness of solar-thermal plants will occur when the conversion efficiency will be significantly increased, and if this improved technology could still be simple, reliable and inexpensive. The desired breakthrough may reside in high-temperature (1,000°C or above) combined-cycle power plants, with gas and steam turbines operating in series, for which the conversion efficiency could reach 60% and the overall efficiency up to 30%. Providing solar heat at these temperatures would involve significant challenges, such as: designing materials for high temperatures, optimizing radiative and convective heat transfer in receivers and optics for high-concentration. OBJECTIVES: The main objectives of this research program are to: 1) study the fundamentals of the volumetric absorption of concentrated solar energy on porous materials, more specifically, semi-transparent reticulated ceramic materials subjected to high-pressure air flows, and then; 2) create “numerical” or virtual reticulated porous ceramics to be investigated by computational means, and simultaneously; 3) formulate, implement and validate a numerical method for fluid flow simulations in porous media, and simultaneously; 4) formulate, implement and validate a numerical method for combined-modes of heat transfer in porous media, and then; 5) combine both methods to investigate the above-mentioned virtual ceramics, and then; 6) experimentally test the conversion performances of real ceramics constructed according to the optimal design, and simultaneously; 7) reformulate parts of the main code based on Lattice Boltzmann methods, which in theory, are required to enhance computational time. OUTCOMES : Outcomes from this research will be a proper understanding of the key of optico-thermal conversion unit (the volumetric absorber) in the global technology. Our country, along with the rest of the world, will face an energy crisis in the decades to come; in this context, research in thermal-energy engineering could potentially lead to the development of new and vital energy and environmental technologies for Canada.