Modeling study of soot formation and oxidation in DI diesel engine using an improved soot model

Abstract

Particulate emission is one of the most deleterious pollutants generated by Diesel fuel combustion. The ability to predict soot formation is one of the key elements needed to optimize the engine performance and minimize soot emissions. This paper reports work on developing, a phenomenological soot model to better model the physical and chemical processes of soot formation in Diesel fuel combustion. This hybrid model features that the effect of turbulence on the chemical reaction rate was considered in soot oxidation. Soot formation and oxidation processes were modeled with the application of a hybrid method involving particle turbulent transport controlled rate and soot oxidation rate. Compared with the original soot model, the in-cylinder pressures, heat release rate and soot emissions predicted by this hybrid model agreed better with the experimental results. The verified hybrid model was used to investigate the effect of injection timing on engine performance. The results show that the new soot model predicted reasonable soot spatial profiles within the combustion chamber. The high temperature gase zone in cylinder for hybrid model case are distributed broadly soot and NOx emission dependence on the start-of-injection (SOI) timing. Retarded SOI timing increased the portion of diffusion combustion and the soot concentration increased significantly with retarding of the fuel injection timing. The predicted distributions of soot concentration and particle mass provide some new insights on the soot formation and oxidation processes in direct injection (DI) engines. The hybrid phenomenological soot model shows greater potential for enhancing understanding of combustion and soot formation processes in DI diesel engines.

Effect of nanostructure, oxidative pressure and extent of oxidation on model carbon reactivity

“…The reduction of soot emissions from diesel engines has been studied through enhancement of fuel formulations, engine designs, and more effective emissioncontrol technology. While soot formation and growth are important, the oxidative reactivity of particles and the conditions under which the particles are generated is tightly coupled to the design of efficient combustion devices for benefiting mitigation [3][4][5][6][7][8][9][10][11][12].…”

Comprehensive Review of the Impact of 2,5-Dimethylfuran and 2-Methylfuran on Soot Emissions: Experiments in Diesel Engines and at Laboratory-Scale

“…However, for decades, a great effort has been devoted to the study of soot formation processes, driven by increasingly restrictive legislation regarding the PM emissions. Therefore, the understanding of the soot formation process has evolved from an empirical and phenomenological description to an era of quantitative models. − Although the soot formation process is not yet fully defined, there are general stages of the processes widely accepted. These stages are summarized in Figure and described below.…”

Semi-physical NOx and soot model for CI engines: Study of its calibration procedure and portability

“…Calibration parameters are supposed to be limited and calibration time low but details are seldom given on this process. [11][12][13][14] Generally speaking, CFD models are not suited for real-time or control-oriented simulations because of their high computation time. As a corollary, CFD models are often validated over a very limited number of points.…”