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CFD Optimization of Exhaust Manifold for Large Diesel Engine Aftertreatment Systems
Technical Paper
2011-01-2199
ISSN: 0148-7191, e-ISSN: 2688-3627
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English
Abstract
To meet EPA Tier IV large diesel engine emission targets, intensive development efforts are necessary to achieve NOx reduction and Particulate Matter (PM) reduction targets [1]. With respect to NOx reduction, liquid urea is typically used as the reagent to react with NOx via SCR catalyst [2]. Regarding to PM reduction, additional heat is required to raise exhaust temperature to reach DPF active / passive regeneration performance window [3]. Typically the heat can be generated by external diesel burners which allow diesel liquid droplets to react directly with oxygen in the exhaust gas [4]. Alternatively the heat can be generated by catalytic burners which enable diesel vapor to react with oxygen via DOC catalyst mostly through surface reactions [5]. The latest technology trend is to combine both mechanisms together so that (1) small-scale burners will enhance exhaust temperature to DOC activation temperature; (2) DOC with HC dosing will raise exhaust temperature to 650 C to achieve active soot reduction [6]. From the scope of system level design, given the added reagents (HC and urea) and heat to exhaust gases, the need arises to achieve even distributions of exhaust gas velocity, good mixing of burner heat with exhaust gas and good mixing of reagents released from HC or urea injectors with exhaust gas, necessitating optimizations of multiphase heat and mass transport phenomena. To meet these multifaceted heat and mass transport targets, geometrical optimizations of subsystems are deemed critical on top of requirements of subcomponents such as burners and injectors. In this paper, the turbo-out manifold box is selected as the subsystem under study for design optimizations. Located between turbo-out ports and exhaust aftertreatment system, the manifold is subject to burner heat injections and diesel liquid injections at multiple locations. The manifold therefore serves the mechanism to distribute exhaust gas, burner heat and diesel vapor. Downstream, the exhaust aftertreatment system incorporates multiple identical flow paths, each encompassing DOC, DPF, urea injectors, SCR, and ASC with complete PM and NOx reduction functionalities. Downstream of the exhaust aftertreatment system, a common stack outlet is created to be open to the environment. The paper discusses general design considerations, performance metrics and methodology for the development of turbo-out manifold with system targets in scope. CFD modeling has been used as the main tool in performing design iterations. Test validations are forthcoming based on these design optimizations.
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Sampath, M., Zheng, G., Zhang, Y., Kotrba, A. et al., "CFD Optimization of Exhaust Manifold for Large Diesel Engine Aftertreatment Systems," SAE Technical Paper 2011-01-2199, 2011, https://doi.org/10.4271/2011-01-2199.Also In
References
- Emissions Standards, USA Locomotives http://www.dieselnet.com/standards/us/loco.php#tier3
- Salanta, G. Zheng, G. Kotrba, A. Rampazzo, R. et al. “Optimization of a Urea SCR System for On-Highway Truck Applications,” SAE Technical Paper 2010-01-1938 2010 10.4271/2010-01-1938
- Kotrba, A. Bai, L. Yetkin, A. Shotwell, R. et al. “DPF Regeneration Response: Coupling Various DPFs with a Thermal Regeneration Unit to Assess System Behaviors,” SAE Technical Paper 2011-01-2200 2011 10.4271/2011-01-2200
- Kotrba, A. Yetkin, A. Gough, B. Gundogan, A. et al. “Performance Characterization of a Thermal Regeneration Unit for Exhaust Emissions Controls Systems,” SAE Technical Paper 2011-01-2208 2011 10.4271/2011-01-2208
- Gardner, T. Yetkin, A. Shotwell, R. Kotrba, A. et al. “Evaluation of a DPF Regeneration System and DOC Performance Using Secondary Fuel Injection,” SAE Technical Paper 2009-01-2884 2009 10.4271/2009-01-2884
- Sampath, M. Zheng, G. Kotrba, A. “Integration of Diesel Burner for Large Engine Aftertreatment using CFD,” SAE Technical Paper 2010-01-1946 2010 10.4271/2010-01-1946
- Zheng, G. Fila, A. Kotrba, A. Floyd, R. “Investigation of Urea Deposits in Urea SCR Systems for Medium and Heavy Duty Trucks,” SAE Technical Paper 2010-01-1941 2010 10.4271/2010-01-1941
- Conway, R. Chatterjee, S. Beavan, A. Lavenius, M. et al. “Combined DPF and SCR Technologies for Heavy Duty Diesel Retrofit,” SAE Technical Paper 2005-01-1862 2005 10.4271/2005-01-1862
- Zheng, G. Palmer, G. Salanta, G. Kotrba, A. “Mixer Development for Urea SCR Applications,” SAE Technical Paper 2009-01-2879 2009 10.4271/2009-01-2879
- Ansys Fluent 12.0 user's guide
- Sampeth, M. Zheng, G. Kotrba, A. “The Role of CFD Combustion Simulation in Diesel Burner Development,” SAE Technical paper 2009-01-2878 2009 10.4271/2009-01-2878
- Weltens, H. Bressler, H. Terres, F. Neumaier, H. Rammoser, D. “Optimization of Catalytic Converter Gas Flow Distribution by CFD Prediction,” SAE Technical paper 930780 1993 10.4271/930780