CRF Research Seeks to Improve Confidence in Large Eddy Simulations

Allowing solutions unattainable with direct numerical simulation and offering far greater accuracy than conventional engineering methods, large eddy simulation (LES) is now widely used for studying complex thermophysics in propulsion and power systems. However, because LES demands extremely complex tools, predictive LES has been problematic, leading to sometimes ambiguous results and suboptimal use of expensive…

New Conceptual Insights into Diesel Engine Fuel-Injection Processes

By Joe Oefelein By combining advanced theory and high-fidelity large eddy simulation, CRF researchers Rainer Dahms and Joe Oefelein have provided new conceptual insights that promise to improve the understanding and prediction of fuel-injection processes at high-pressure diesel engine conditions. Their results, which were corroborated by experiments performed by CRF researchers Lyle Pickett and Julien…

New Polarized-Depolarized Measurement Capability Extends Use of Raman/Rayleigh Methods to More Flame Types

By Robert Barlow Allowing single-shot measurements of all major species in nonsooting flames of simple fuels, such as H2 and CH4, spontaneous Raman scattering has been a key CRF laser diagnostic technique for fundamental turbulent-combustion studies. However, laser-induced fluorescence from soot precursors tends to interfere significantly with Raman scattering signals—limiting this method’s utility. Such fluorescence…