English
 
Help Privacy Policy Disclaimer
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT

Released

Paper

Technical Note: Influence of surface roughness and local turbulence on coated-wall flow tube experiments for gas uptake and kinetic studies

MPS-Authors
/persons/resource/persons204129

Li,  G.
Multiphase Chemistry, Max Planck Institute for Chemistry, Max Planck Society;

/persons/resource/persons101295

Su,  H.
Multiphase Chemistry, Max Planck Institute for Chemistry, Max Planck Society;

/persons/resource/persons203111

Kuhn,  U.
Multiphase Chemistry, Max Planck Institute for Chemistry, Max Planck Society;

/persons/resource/persons133113

Meusel,  H.
Multiphase Chemistry, Max Planck Institute for Chemistry, Max Planck Society;

/persons/resource/persons101189

Pöschl,  U.
Multiphase Chemistry, Max Planck Institute for Chemistry, Max Planck Society;

/persons/resource/persons127588

Cheng,  Y. F.
Multiphase Chemistry, Max Planck Institute for Chemistry, Max Planck Society;

External Resource
No external resources are shared
Fulltext (restricted access)
There are currently no full texts shared for your IP range.
Fulltext (public)
There are no public fulltexts stored in PuRe
Supplementary Material (public)
There is no public supplementary material available
Citation

Li, G., Su, H., Kuhn, U., Meusel, H., Ammann, M., Shao, M., et al. (2017). Technical Note: Influence of surface roughness and local turbulence on coated-wall flow tube experiments for gas uptake and kinetic studies. Atmospheric Chemistry and Physics Discussions, 17.


Cite as: https://hdl.handle.net/11858/00-001M-0000-002D-AADB-6
Abstract
Coated-wall flow tube reactors are frequently used to investigate gas uptake and heterogeneous or multiphase reaction kinetics under laminar flow conditions. Coating surface roughness may potentially distort the laminar flow pattern, induce turbulence and introduce uncertainties in the calculated uptake coefficient based on molecular diffusion assumptions (e.g., Brown/CKD/KPS methods), which hasn't been sufficiently addressed in previous applications. Here we investigate the influence of surface roughness and local turbulence on coated-wall flow tube experiments for gas uptake and kinetic studies. According to laminar boundary theory and considering the specific flow conditions in a coated-wall flow tube, we suggest using a critical height δc to evaluate turbulence effects in the design and analysis of coated-wall flow tube experiments. When a coating thickness εmax is larger than δc, the roughness elements of the coating may cause local turbulence and result in overestimation of the real uptake coefficient (γ). We collect εmax values in previous coated-wall flow tube studies and evaluate their roughness effects using the criterion of δc. In most cases, the roughness doesn't generate turbulence and has negligible effects. When turbulence is generated, the calculated effective uptake coefficient (γeff) can bear large difference compared to the real uptake coefficient (γ). Their difference becomes less for gas reactants with lower uptake (i.e., smaller γ), or/and for a smaller ratio of the coating thickness εmax/R0 to the flow tube radius R0, (εmax/R0). On the other hand, the critical height δc can also be adjusted by optimizing flow tube configurations and operating conditions (i.e., tube diameter, length and flow velocity), to ensure not only an unaffected laminar flow pattern but also a flexible residence time of gas reactants in flow tube reactors.