This title appears in the Scientific Report :
2006
Please use the identifier:
http://hdl.handle.net/2128/548 in citations.
Eduktvorbereitung und Gemischbildung in Reaktionsapparaten zur autothermen Reformierung von dieselähnlichen Kraftstoffen
Eduktvorbereitung und Gemischbildung in Reaktionsapparaten zur autothermen Reformierung von dieselähnlichen Kraftstoffen
This thesis deals with the optimization of the mixture formation in an autothermal reformer in a diesel-based fuel processing system for a polymer electrolyte fuel cell as an auxiliary power unit (APU) in automotive applications. For this purpose computational fluid dynamics (CFD) was widely used. C...
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Personal Name(s): | Por$\check{s}$, Zden$\check{e}$k (Corresponding author) |
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Contributing Institute: |
Energieverfahrenstechnik; IWV-3 |
Imprint: |
Jülich
Forschungszentrum Jülich Gmbh Zentralbibliothek, Verlag
2006
|
Physical Description: |
XX, 182, XII S. |
Dissertation Note: |
RWTH Aachen, Diss., 2005 |
ISBN: |
3-89336-432-2 |
Document Type: |
Book Dissertation / PhD Thesis |
Research Program: |
Rationelle Energieumwandlung |
Series Title: |
Schriften des Forschungszentrum. Reihe Energietechnik / Energy Technology
49 |
Subject (ZB): | |
Link: |
OpenAccess |
Publikationsportal JuSER |
This thesis deals with the optimization of the mixture formation in an autothermal reformer in a diesel-based fuel processing system for a polymer electrolyte fuel cell as an auxiliary power unit (APU) in automotive applications. For this purpose computational fluid dynamics (CFD) was widely used. CFD simulations have been verified by flow visualization experiments. Additional experiments were carried out to extend the required knowledge of the mixing process. ATR-5A, the autothermal diesel reformer of the fifth generation designed in Forschungszentrum Jülich is taken as the starting point of this thesis. In the mixing chamber of this reactor the educts air, steam and fuel are mixed. The liquid fuel is injected and atomized using a special two-fluid nozzle and evaporated by the superheated steam. Complete fuel evaporation is required to obtain a homogeneous mixture of the educts. In the time being the carbon formation is globally addressed to be one of the greatest barriers in diesel reforming. Aromatics content and diesel components with higher boiling temperatures are mainly responsible for this process, as described in this work and verified by the experiments carried out in /1/. CFD simulations consist of the modeling of turbulent flow and mixing of the three gases air, steam and fuel vapor. The spray profile of the injected fuel and its evaporation was also calculated. Possible chemical pre-reactions in the mixing chamber were considered. Via CFD it is possible to identify and adjust the optimal operating conditions of the reactor ATR-5A. ATR-5B, which is an optimized version of this reactor, was designed for a higher power scale. This reactor is especially suitable for kerosene. Experiments with colored fluids in model reactors build with quartz glass were carried out for visualization of the turbulent flow to verify the CFD simulations. In addition, the spray profile characteristics of the used atomizing nozzles were investigated in glass reactors. A good agreement of the flow characteristics was observed between the experiments and CFD simulations. Two new mixing chamber concepts for the operation with commercial diesel fuels were developed and analyzed. Autothermal reformers of the seventh and eight generation ATR-7 and ATR-8 based on these new concepts were designed and tested. This thesis confirms CFD as an important tool for optimizing mixing processes in reaction apparatuses. |