Transport Phenomena in Energy Conversion Systems

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Transport phenomena play a dominant role in determining the efficiency and emissions of energy conversion systems for power generation, such as internal combustion engines (ICEs) and fuel cells, through competition with reaction. ICEs are a major part of today's energy systems, but with emissions of harmful chemicals and global warming gases; fuel cells with emission of water are considered clean energy conversion essential for future sustainable energy systems. The proposed research focuses on the study of transport phenomena for cost-effective high-efficiency clean energy systems for practical applications as a long-term objective, and 1) low-emission high-efficiency direct injection ICEs and 2) low-cost high-volume production techniques for the fabrication of proton exchange membrane fuel cells (PEMFCs) as a short-term objective. Hence the proposed research is targeted for maximum impact today and in the future. In direct injection gasoline engines, fuel sprays impinge on the combustion chamber walls creating a thin fuel film; the film mass cannot be burned completely near the wall and becomes a major source of emissions. PEMFC fabrication is a bottleneck in commercialization, and it involves spraying catalyst ink, a liquid solution with catalyst nanoparticles dispersed, on a substrate surface to form catalyst layers when the liquid is evaporated. Central to both is the impingement of sprays on a heated surface covered by a thin film of liquid, and has significant fundamental and practical importance. To achieve the objectives, both experimental and numerical studies will be carried out to improve the fundamental understanding, and novel approaches will be developed 1) to use the splash created by spray impingement to reduce/eliminate the surface liquid fuel film in engines for the reduction/elimination of the associated emissions; and 2) to eliminate splash during spray deposition, avoiding expensive catalyst waste while controlling the surface liquid evaporation process to achieve the desired quality and consistency in the PEMFC fabrication. The current state of the art is that splash in spray impingement always exists, but only partial liquid splashes. The proposed research program will help improve the knowledge of multi-phase flow with heat and mass transfer in general, and specifically spray-surface interaction laden with and without solid particles on the fundamental side; and will help in practice reduce the emission of high-efficiency direct-injection engines, and will help reduce the cost and enhance the performance and durability of PEMFCs that can be manufactured reliably and consistently in large volume. Further, the knowledge and expertise developed and high-quality personnel trained will expand and enhance the capability of Canadian automotive and fuel cell industry, contributing to the development of knowledge-based Canadian economy. The clean energy technology developed will have significant environmental benefits.