Nicolas Hafen

Dr. Nicolas Hafen

Karlsruhe Institute for Technology (KIT)
orcid

Research Focus & Metrics

Academic Career Length

12Years (2015-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 January 2021 in Computers & Mathematics with Applications
Verified
Journal Article
Open access
MKMathias J. Krause
Mathias J. Krause
AKAdrian Kummerländer
Adrian Kummerländer
SASamuel J. Avis
Samuel J. Avis
HKHalim Kusumaatmaja
Halim Kusumaatmaja
DDDavide Dapelo
Davide Dapelo
SSStephan Simonis
Stephan Simonis

1 December 2015 in Chemical Engineering Science
Verified
Journal Article
Closed access
MWM. Wallenstein
M. Wallenstein
NHNicolas Hafen
Nicolas Hafen
HHH. Heinzmann
H. Heinzmann
SSS. Schug
S. Schug
WAW. Arlt
W. Arlt
BDB. Dietrich
B. Dietrich

27 January 2021 in Computation
Verified
Journal Article
Open access
PDF file
RTRobin Trunk
Robin Trunk
TWTimo Weckerle
Timo Weckerle
NHNicolas Hafen
Nicolas Hafen
GTGudrun Thaeter
Gudrun Thaeter
HNHermann Nirschl
Hermann Nirschl
MKMathias J. Krause
Mathias J. Krause
The simulation of surface resolved particles is a valuable tool to gain more insights in the behaviour of particulate flows in engineering processes. In this work the homogenized lattice Boltzmann method as one approach for such direct numerical simulations is revisited and validated for different scenarios. Those include a 3D case of a settling sphere for various Reynolds numbers. On the basis of this dynamic case, different algorithms for the calculation of the momentum exchange between fluid and particle are evaluated along with different forcing schemes. The result is an updated version of the method, which is in good agreement with the benchmark values based on simulations and experiments. The method is then applied for the investigation of the tubular pinch effect discovered by Segré and Silberberg and the simulation of hindered settling. For the latter, the computational domain is equipped with periodic boundaries for both fluid and particles. The results are compared to the model by Richardson and Zaki and are found to be in good agreement. As no explicit contact treatment is applied, this leads to the assumption of sufficient momentum transfer between particles via the surrounding fluid. The implementations are based on the open-source C++ lattice Boltzmann library OpenLB.

15 January 2024 in Computers in Biology and Medicine
Verified
Journal Article
Closed access
FPFrantišek Prinz
František Prinz
JPJan Pokorný
Jan Pokorný
JEJakub Elcner
Jakub Elcner
FLFrantisek Lizal
Frantisek Lizal
OMOndrej Mišík
Ondrej Mišík
MJMiroslav Jícha
Miroslav Jícha

7 February 2023 in Journal of Fluid Mechanics
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Journal Article
Open access
PDF file
NHNicolas Hafen
Nicolas Hafen
JTJulia R.D. Thieringer
Julia R.D. Thieringer
JMJörg Meyer
Jörg Meyer
MKMatthias Krause
Matthias Krause
ADAchim Dittler
Achim Dittler
The exhaust from combustion engines contains particulate matter (PM), which poses potential health risks to human lungs. Current emission laws place increasingly strict limitations on both PM and particle number, leading to the necessity of using wall-flow filters to separate out a significant amount of the introduced PM. As this leads to an increase in the filter's loading, it is regenerated continuously or periodically, leading to the rearrangement of individual particulate structures inside the filter channels. Such rearrangement events cause the formation of specific deposition patterns, which affect the filter's pressure drop, its loading capacity and the separation efficiency. In order to derive predictions on the formation of specific deposition patterns, the transient behaviour of individual particle structures needs to be examined. The present work investigates the detachment and transport of particle structures during filter regeneration with three-dimensional surface-resolved simulations using a lattice Boltzmann method. The goal of this work is the determination of relevant key quantities and their interpretation with respect to predictions regarding the resulting deposition patterns. In this context, it is shown that lift forces are not the predominant detachment forces for non-spherical particle structures, and that the stopping distance of such structures is too long to avoid back-end deposition.