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

摘要1258702/1258594/1258697 White，Christopher/Jansons，Marcis/Dubief，Yves了解和预测内燃机内的热传递对于优化燃油效率，减少有害的发动机排放，以及进一步推进先进的燃烧策略至关重要。本研究项目将研究快速瞬变和往复效应对发动机内热传递的影响。该项目的动机是现有的传热模型不能准确地捕捉到这些影响，进而无法准确地预测典型驾驶周期内的传热。建模的困难是由于缸内湍流、燃油喷射、燃烧、活塞几何形状和活塞运动之间的非线性相互作用，这些因素在气缸壁上产生了复杂的热边界层。研究人员将利用免费的实验室和数值实验进行系统的科学调查，重点了解这些非线性相互作用如何影响气缸内的换热。在这些基础研究的同时，研究人员将开发一种新型的双波长红外(IR)温度诊断技术，能够以非常高的时间(KHz)和空间分辨率(&amp；#956；m)获取二维表面温度。这种双波长红外诊断将用于测量活塞表面温度和燃烧光学发动机在不同发动机条件和燃烧模式下的局部热流密度。这些研究的综合目标是推进发动机热传递的基本知识基础，并建立考虑发动机快速瞬变和往复效应影响的热传递模型。本项目旨在提高发动机热传递模型的稳健性，以便将其用于工程设计。技术影响是有可能优化发动机设计，以减少热损失，提高热效率，并消除实际实施低排放、高效率、低温燃烧(LTC)发动机技术的障碍。改进的发动机设计和LTC发动机技术的实施对社会和环境的影响是提高燃油经济性，减少温室气体排放和大气污染物。此外，该项目将用于吸引和培养对能源、燃烧、流体动力学和内燃机领域感兴趣的高素质本科生和研究生。最后，拟议的研究将被纳入现有的K-12外联方案，通过引入侧重于具体项目主题的活动，即运输和内燃机。

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.