An experimental and numerical study on effects of exhaust gas temperature and flow rate on deposit formation in Urea-Selective Catalytic Reduction (SCR) system of modern automobiles
| Autor: | N. Kapilan, S Sadashiva Prabhu, Vijaykumar Hindasageri, Nagaraj S. Nayak |
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| Rok vydání: | 2017 |
| Předmět: |
Materials science
020209 energy Energy Engineering and Power Technology Exhaust gas Reynolds number Thermodynamics Selective catalytic reduction 02 engineering and technology Industrial and Manufacturing Engineering Forced convection Volumetric flow rate symbols.namesake 020401 chemical engineering Thermal Heat transfer 0202 electrical engineering electronic engineering information engineering symbols 0204 chemical engineering NOx Simulation |
| Zdroj: | Applied Thermal Engineering. 111:1211-1231 |
| ISSN: | 1359-4311 |
| DOI: | 10.1016/j.applthermaleng.2016.09.134 |
| Popis: | Urea Water Solution (UWS) is injected to generate NH3 in Selective Catalytic Reduction (SCR) system of modern automobiles. Thermal and fluid dynamic conditions such as temperature and Reynolds number of the flow favors ammonia generation in terms of heat transfer to UWS droplets by forced convection. During extremely cold weather conditions and low exhaust temperatures, the overdosing of UWS results in deposits of urea and its byproducts. As deposit depletion changes the stoichiometry of NOx/NH3, any predictive method becomes complementary to experimental studies on deposit formation. In the present work, we experimentally investigated deposit formation and its rate by a newer concept of usage of Stainless Steel (SS) foils considering temperature and flow rate as variables. According to numerical results, the droplet evaporation of UWS decreases as flow rate increases. For a fixed rate of UWS quantity of deposits decrease with increase in temperature and flow rate. Accordingly, structural changes are observed. Numerical values of time dependent deposit formation found slightly superior to the experimental values. The study revealed that deposit areas at low temperatures are comparable to numerical values. Phenomenological model is proposed to find deposit conversion factor for low temperatures (150–250°C), which helps in tuning of UWS dosage strategy to prevent NH3 slip. |
| Databáze: | OpenAIRE |
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