a computational optimization was performed for a direct-injection diesel engine using three-dimensional modeling. fully transient cfd analyses of different valve profile strategies for the intake and compression strokes were performed to evaluate the effects on both engine performance and in-cylinder flow-field evolution. the turbulence model was used along with the second order linear upwind s...

A computational optimization was performed for a direct-injection diesel engine using three-dimensional modeling. Fully transient CFD analyses of different valve profile strategies for the intake and compression strokes were performed to evaluate the effects on both engine performance and in-cylinder flow-field evolution. The turbulence model was used along with the second order linear upwin...

A detailed chemistry-based CFD model was developed to simulate the diesel spray combustion and emission process. A reaction mechanism of n-heptane is coupled with a reduced NOx mechanism to simulate diesel fuel oxidation and NOx formation. The soot emission process is simulated by a phenomenological soot model that uses a competing formation and oxidation rate formulation. The model is applied ...

In order to evaluate different port concepts for modern Compression-Ignition engines, usually quantities as the swirl level and the flow coefficient are evaluated, which are measured on a stationary flow test bench. As additional criterion, in this work, the homogeneity of the swirl flow is introduced and defined quantitatively. Different valve lift strategies are evaluated using three-dimensio...

Computational Fluid Dynamic (CFD) simulations using the AVL Fire and Kiva 3v codes were performed to examine commonly accepted techniques and assumptions used when simulating direct injection diesel engines. Simulations of a steady state impulse swirl meter validated the commonly used practice of evaluating the swirl ratio of diesel engines by integrating the valve flow and torque history over ...

Soot concentration distribution is investigated both numerically and experimentally in methane-air diffusion flame. The experimental work is conducted with a cylindrical swirl stabilized combustor. Filter paper technique is used to measure soot volume fraction inside the combustor. The numerical simulation is based on the solution of the fully-coupled conservation equations for swirling turbule...

One of the important problems in reducing pollutant emission from diesel engines is trade-off between soot and NOx. Split injection is one of the most powerful tools that decrease soot and NOx emissions simultaneously. At the present work, the effect of split injection on the combustion process and emissions of a direct-injection diesel engine under full-load conditions is investigated by the c...

conventional compression ignition (ci) engines are known for their high thermal efficiency compared to spark ignited (si) engines. gasoline because of its higher ignition delay has much lower soot emission in comparison with diesel fuel. using double injection strategy reduces the maximum heat release rate that leads to nox emission reduction. in this paper, a numerical study of a gasoline fuel...

A multi-pulse injection strategy for premixed charge compression ignition (PCCI) combustion was investigated in a four-valve, direct-injection diesel engine by a computational fluid dynamics (CFD) simulation using KIVA-3V code coupled with detailed chemistry. The effects of fuel splitting proportion, injection timing, spray angles, and injection velocity were examined. The mixing process and fo...

The potential of Palm Methyl Esters (PME) as an alternative fuel for gas turbines is investigated using a swirl burner. The main air flow is preheated to 623 K and a swirling spray flame is established at atmospheric pressure. The spray combustion characteristics of PME are compared to diesel and Jet-A1 fuel under the same burner power output of 6 kW. Investigation of the fuel atomizing charact...