Transport Phenomena in Energy Conversion Systems

热量和质量传递在能量转换系统的设计和性能中起着至关重要的作用。提出的研究有两个组成部分：(i)质子交换膜（PEM）燃料电池，被认为是未来可持续能源系统的一部分；（ii）柴油发动机中的燃料雾化和喷雾，这是当今能源系统的重要组成部分。因此，（ii）是目前影响最大的目标，(i)是长期收益的目标。****PEM燃料电池越来越多地被设计为在高电流（功率）密度下工作，以解决成本和性能的关键技术挑战，这需要对燃料电池组件中的热量和质量传输现象有透彻的了解。虽然气体扩散层可以获得精确的传输特性，但微孔层和催化剂层的传输特性就更少了。本研究将对微孔和催化剂层的输运特性进行协调的实验和理论分析，以获得准确可靠的数据。研究结果将对加拿大燃料电池工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策略。随着喷射压力的增加，燃油蒸气（空化）在喷油器内壁附近形成并到达喷油器出口；此后，燃料蒸气趋向于凝结成液相。液体堆芯上的燃料冷凝妨碍了液体的雾化。本研究将研究喷射器内部的空化现象及其相互作用和对后续液心雾化和喷雾特性的影响。将采用实验和建模相结合的方法来提高喷油器的性能，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.