NSF/DOE Advanced Combustion Engines: Collaborative Research: A Comprehensive Investigation of Unsteady Reciprocating Effects on Near-Wall Heat Transfer in Engines

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Abstract1258702 / 1258594 / 1258697White, Christopher / Jansons, Marcis / Dubief, YvesThe capacity to understand and predict heat transfer in internal combustion engines is critically important for optimizing fuel efficiency, reducing harmful engine-out emissions, and furthering advanced combustion strategies. This research project will investigate the effects of rapid transients and reciprocating effects on heat transfer in engines. The project is motivated by the fact that existing heat transfer models cannot accurately capture these effects, and in turn cannot accurately predict heat transfer over a typical drive cycle. The modeling difficulty is owed to nonlinear interactions between in-cylinder turbulence, fuel injection, combustion, piston geometry, and piston motion that produce complex thermal boundary layers along the cylinder walls. The researchers will use complimentary laboratory and numerical experiments to conduct a systematic scientific investigation focused on understanding how these nonlinear interactions affect in-cylinder heat transfer. In parallel to these fundamental studies, the researchers will develop a novel two-wavelength infrared (IR) temperature diagnostic capable of acquiring two-dimensional surface temperatures with very high temporal (kHz) and spatial resolution (μm). This dual-wavelength IR diagnostic will be used to measure piston surface temperature and local heat flux in a fired optical engine for varying engine conditions and combustion modes. The combined objective of these studies is to advance the fundamental knowledge base of thermal transport in engines and to formulate heat transfer models that account for the effects of rapid transients and reciprocating effects in engines.This project intends to improve upon the robustness of engine heat transfer models so that they can be used for engineering design. The technological impact is the potential to optimize engine designs for reduced heat loss, improved thermal efficiency, and the removal of barriers to practical implementation of low-emission, high efficiency, low temperature combustion (LTC) engine technologies. The societal and environmental impacts of improved engine designs and implementation of LTC engine technologies are improved fuel economy, and a reduction in greenhouse emissions and atmospheric pollutants. In addition, the project will be used to attract and train highly qualified undergraduate and graduate students interested in the fields of energy, combustion, fluid dynamics, and internal combustion engines. Lastly, the proposed research will be leveraged into existing K-12 outreach programs by introducing activities focused on project specific themes, namely transport and internal combustion engines.