Transport Phenomena in Energy Conversion Systems

热质传输在能量转换系统的设计和性能中起着至关重要的作用。这项拟议的研究包括两个部分：(I)被认为是未来可持续能源系统一部分的质子交换膜(PEM)燃料电池，以及(Ii)柴油发动机中的燃料雾化和喷雾，这是当今能源系统的相当大一部分。因此，(Ii)今天的目标是产生最大影响，(I)是为了长期收益。PEM燃料电池越来越多地设计为在高电流(功率)密度下运行，以解决成本和性能方面的关键技术挑战，这要求对燃料电池组件中的热和质量传输现象有深入的了解。虽然气体扩散层具有精确的传输特性，但微孔层的传输特性较少，催化层的传输特性更少。拟议的研究将进行协调的实验和理论分析，以获得关于微孔和催化剂层中传输性质的准确和可靠的数据。这一结果将对加拿大燃料电池行业的产品开发特别有用。高压柴油喷射是清洁柴油发动机的一种战略。随着喷油压力的增加，燃油蒸汽(空化)在喷油器内部壁面附近形成，并到达喷油器出口；此后，燃油蒸汽倾向于凝结成液体。燃料在液芯上的冷凝会干扰液体的雾化。这项研究将研究喷嘴内部的空化现象及其对后续液芯雾化和喷雾特性的相互作用和影响。为了改善喷油器的性能，将采用实验和模拟相结合的方法，这将有助于缸内燃烧和减少污染物。

Heat and mass transport play critical roles in the design and performance of energy conversion systems. The proposed research has two components: (i) proton exchange membrane (PEM) fuel cells, considered part of future sustainable energy systems, and (ii) fuel atomization and sprays in diesel engines, a considerable part of today's energy systems. Hence, (ii) is targeted for maximum impact today and (i) for long-term gain. PEM fuel cells are increasingly designed to operate at high current (power) densities to address the critical technical challenges of cost and performance, requiring a thorough understanding of heat and mass transport phenomena in fuel cell components. While accurate transport properties are available for the gas diffusion layer, fewer are available for the microporous layer and even less for the catalyst layer. The proposed research will conduct a coordinated experimental and theoretical analysis to obtain accurate and reliable data for the transport properties in the microporous and catalyst layers. The results will be particularly useful for the Canadian fuel cell industry in their product development.High-pressure diesel injection is a strategy for clean diesel engines. With increased injection pressure, fuel vapor (cavitation) forms near the wall inside the injector and reaches the injector exit; thereafter fuel vapor tends to condense into the liquid phase. Fuel condensation on the liquid core interferes with the atomization of liquid. The proposed research will study the cavitation phenomena inside the injector and its interaction and impact on the subsequent liquid core atomization and spray characteristics. Both experimental and modeling approaches will be conducted to improve fuel injector performance, which will be useful for in-cylinder combustion and pollutant reduction.