Combined experimental and numerical studies on soot characteristics of diesel sprays with split injection strategies

Experimental and numerical studies on the soot characteristics of Spray A flames were conducted with a focus effects different split injection strategies in high-pressure high-temperature vessels within engine combustion network. Three high-speed imaging techniques used to obtain transient information flame evolution. Schlieren was applied identify spray boundaries penetration. Moreover, combined extinction radiation technique quantify spatial temperature fields simultaneously. Finally, OH* chemiluminescence at baseline condition measure temporal To substantiate analysis, experimental results compared computational fluid dynamics (CFD) predictions from Reynolds-averaged Navier Stokes approach Unsteady Flamelet Progress Variable two-equation soot-in-flamelet models, which qualitatively reproduced results. According chosen strategy, dwell first-injection pulse durations varied. For all cases, ignition delay (ID) production second-injection shorter higher than those first one, respectively. slight change observed when time changed. The CFD calculations revealed small reduction ID second long times, due variations interaction between newly injected fuel recession. However, effect variation extremely produce significant differences evolution pulse, neither nor production. With regard duration injection, no despite noticeable pulse. indicated that because quasi-steady flow process near nozzle along region close identical first-pulse-duration only occurring tip jet. Thus, occurred under conditions for Although sensitivity both first-pulse low, analysis highlighted important end-of-injection wave propagation recession