High-Efficiency and Low-Emissions Engines: the Need for High End Computing

Abstract

Concerns about energy security, greenhouse gas emissions, and toxic emissions are driving engine manufacturers to develop new engines that have both high efficiency and very low emissions of nitric oxides (NO_X ) and particulates.  Advanced combustion processes such as homogeneous charge compression ignition (HCCI) and low-temperature diesel combustion can potentially meet these requirements, but there are significant technical challenges.  Overcoming these challenges requires an improved understanding of the in-cylinder processes, and substantial research and development efforts are underway.  The principles of these advanced combustion techniques, the main technical challenges, and recent experimental results will be presented and discussed.  These experimental efforts have added substantially to our understanding of the in-cylinder processes in these advanced engines; however, several aspects cannot readily be determined from experiments and remain poorly understood.  High-end computing (HEC) is uniquely capable of supplementing the experimental results to provide this additional information.  Used in this manner, HEC has the potential to improve our fundamental understanding of such critical factors as fuel-spray breakup, flame stabilization, in-cylinder flows and turbulence, and the coupling between turbulence and autoignition kinetics.  HEC also has the potential to help in the development and testing of advanced submodels (e.g., turbulence and fuel-spray breakup) that would improve the accuracy of the Reynolds Averaged Navier-Stokes (RANS) models, which are a primary engine design tool.