Integration of Diesel Burner for Large Engine Aftertreatment using CFD 2010-01-1946
Diesel burners recently have been used in Diesel Particulate Filter (DPF) regeneration process, in which the exhaust gas temperature is raised through the combustion process to burn off the soot particles. The feasibility of such process using the burner in large diesel applications is investigated along with a mixer and DPF. For such applications, only partial flow of the exhaust stream is fed into the burner and the resulting hot flow from combustion process is then mixed with the rest of the main stream. The amount of flow into the burner plays a vital role in overall system performance as it determines the amount of hot gas needed for Diesel Oxidation Catalyst (DOC) light-off (to facilitate DPF regeneration) and also oxygen amount needed for secondary combustion. A passive valve plate design is proposed for such flow split applications for the burner. The valve should operate at various positions at different flow rates to vary the flow split into the burner to achieve complete combustion and proper mixing. The valve position is not the only factor that determines the flow split into the burner, there are other factors such as combustion pressure, and air-fuel ratio, etc. that also play a major role. Since testing of such a large system is not feasible in the early design stage, CFD diesel combustion modeling is used to determine the system backpressure and flow split to the burner at various valve operating conditions. This work provides correlations of the torque data experienced by the valve which can be used to design a spring for such system. The first phase of the work is to run the cold flow analysis to determine the flow split and back pressure caused by different valve positions. And the second phase of the work is to repeat the former one with combustion process activated. From the results, the methodology of a burner integration and slipstream valve plate design for large engine application is studied and evaluated.