CFD Simulation of SCR Systems Using a Mass-Fraction-Based Impingement Model
Computational fluid dynamics (CFD) are an essential tool for the development of diesel engine aftertreatment systems using selective catalytic reduction (SCR) to reduce nitrous oxides (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline">&...
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2023-07-01
|
| Series: | Fluids |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2311-5521/8/8/216 |
| _version_ | 1797584785575510016 |
|---|---|
| author | Max Quissek Uladzimir Budziankou Sebastian Pollak Thomas Lauer |
| author_facet | Max Quissek Uladzimir Budziankou Sebastian Pollak Thomas Lauer |
| author_sort | Max Quissek |
| collection | DOAJ |
| description | Computational fluid dynamics (CFD) are an essential tool for the development of diesel engine aftertreatment systems using selective catalytic reduction (SCR) to reduce nitrous oxides (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>NO</mi><mi mathvariant="normal">x</mi></msub></semantics></math></inline-formula>). In urea-based SCR, liquid urea–water solution (UWS) is injected into the hot exhaust gas, where it transforms into gaseous ammonia. This ammonia serves as a reducing agent for <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>NO</mi><mi mathvariant="normal">x</mi></msub></semantics></math></inline-formula>. CFD simulations are used to predict the ammonia distribution in the exhaust gas at the catalyst inlet. The goal is to achieve the highest possible uniformity to realize homogeneous <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>NO</mi><mi mathvariant="normal">x</mi></msub></semantics></math></inline-formula> reduction across the catalyst cross section. The current work focuses on the interaction of UWS droplets with the hot walls of the exhaust system. This is a crucial part of the preparation of gaseous ammonia from the injected liquid UWS. Following experimental investigations, a new impingement model is described based on the superposition of four basic impingement behaviors, each featuring individual secondary droplet characteristics. The droplet–wall heat transfer, depending on surface temperature and impingement behavior, is also calculated using a newly parameterized model. Applying the presented approach, the cooling of a steel plate from intermittent spray impingement is simulated and compared to measurements. The second validation case is the distribution of ammonia at the catalyst inlet of an automotive SCR system. Both applications show good agreement and demonstrate the quality of the new model. |
| first_indexed | 2024-03-10T23:57:38Z |
| format | Article |
| id | doaj.art-bcba91be2e3f4179a1cf99ab33e4b30e |
| institution | Directory Open Access Journal |
| issn | 2311-5521 |
| language | English |
| last_indexed | 2024-03-10T23:57:38Z |
| publishDate | 2023-07-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Fluids |
| spelling | doaj.art-bcba91be2e3f4179a1cf99ab33e4b30e2023-11-19T01:04:31ZengMDPI AGFluids2311-55212023-07-018821610.3390/fluids8080216CFD Simulation of SCR Systems Using a Mass-Fraction-Based Impingement ModelMax Quissek0Uladzimir Budziankou1Sebastian Pollak2Thomas Lauer3Institute of Powertrains and Automotive Technology, TU Wien, Getreidemarkt 9, Object 1, 1060 Vienna, AustriaInstitute of Powertrains and Automotive Technology, TU Wien, Getreidemarkt 9, Object 1, 1060 Vienna, AustriaInstitute of Powertrains and Automotive Technology, TU Wien, Getreidemarkt 9, Object 1, 1060 Vienna, AustriaInstitute of Powertrains and Automotive Technology, TU Wien, Getreidemarkt 9, Object 1, 1060 Vienna, AustriaComputational fluid dynamics (CFD) are an essential tool for the development of diesel engine aftertreatment systems using selective catalytic reduction (SCR) to reduce nitrous oxides (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>NO</mi><mi mathvariant="normal">x</mi></msub></semantics></math></inline-formula>). In urea-based SCR, liquid urea–water solution (UWS) is injected into the hot exhaust gas, where it transforms into gaseous ammonia. This ammonia serves as a reducing agent for <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>NO</mi><mi mathvariant="normal">x</mi></msub></semantics></math></inline-formula>. CFD simulations are used to predict the ammonia distribution in the exhaust gas at the catalyst inlet. The goal is to achieve the highest possible uniformity to realize homogeneous <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>NO</mi><mi mathvariant="normal">x</mi></msub></semantics></math></inline-formula> reduction across the catalyst cross section. The current work focuses on the interaction of UWS droplets with the hot walls of the exhaust system. This is a crucial part of the preparation of gaseous ammonia from the injected liquid UWS. Following experimental investigations, a new impingement model is described based on the superposition of four basic impingement behaviors, each featuring individual secondary droplet characteristics. The droplet–wall heat transfer, depending on surface temperature and impingement behavior, is also calculated using a newly parameterized model. Applying the presented approach, the cooling of a steel plate from intermittent spray impingement is simulated and compared to measurements. The second validation case is the distribution of ammonia at the catalyst inlet of an automotive SCR system. Both applications show good agreement and demonstrate the quality of the new model.https://www.mdpi.com/2311-5521/8/8/216SCRimpingementspray coolingCFDammonia uniformity |
| spellingShingle | Max Quissek Uladzimir Budziankou Sebastian Pollak Thomas Lauer CFD Simulation of SCR Systems Using a Mass-Fraction-Based Impingement Model Fluids SCR impingement spray cooling CFD ammonia uniformity |
| title | CFD Simulation of SCR Systems Using a Mass-Fraction-Based Impingement Model |
| title_full | CFD Simulation of SCR Systems Using a Mass-Fraction-Based Impingement Model |
| title_fullStr | CFD Simulation of SCR Systems Using a Mass-Fraction-Based Impingement Model |
| title_full_unstemmed | CFD Simulation of SCR Systems Using a Mass-Fraction-Based Impingement Model |
| title_short | CFD Simulation of SCR Systems Using a Mass-Fraction-Based Impingement Model |
| title_sort | cfd simulation of scr systems using a mass fraction based impingement model |
| topic | SCR impingement spray cooling CFD ammonia uniformity |
| url | https://www.mdpi.com/2311-5521/8/8/216 |
| work_keys_str_mv | AT maxquissek cfdsimulationofscrsystemsusingamassfractionbasedimpingementmodel AT uladzimirbudziankou cfdsimulationofscrsystemsusingamassfractionbasedimpingementmodel AT sebastianpollak cfdsimulationofscrsystemsusingamassfractionbasedimpingementmodel AT thomaslauer cfdsimulationofscrsystemsusingamassfractionbasedimpingementmodel |